Cloud Tracker Weather Instrument

Wednesday June 29, 2011

One of the most remarkable images of our planet has always been how dynamic the atmosphere is a photo of the Earth taken from space usually shows swirling masses of white wispy clouds, circling and moving constantly. So what are these graceful puffs that can both frustrate astronomers and excite photographers simultaneously?


Clouds are frozen ice crystals or white liquid water that you can see with your eyes. Scientists who study clouds go into a field of science called nephology, which is a specialized area of meteorology. Clouds don’t have to be made up of water – they can be any visible puff and can have all three states of matter (solid, liquid, and gas) existing within the cloud formation. For example, Jupiter has two cloud decks: the upper are water clouds, and the lower deck are ammonia clouds.


We’re going to learn how to build a weather instrument that will record whether (weather?) the day was sunny or cloudy using a very sensitive piece of paper. Are you ready?


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Thermometer

Wednesday June 29, 2011

First invented in the 1600s, thermometers measure temperature using a sensor (the bulb tip) and a scale. Temperature is a way of talking about, measuring, and comparing the thermal energy of objects. We use three different kinds of scales to measure temperature. Fahrenheit, Celsius, and Kelvin. (The fourth, Rankine, which is the absolute scale for Fahrenheit, is the one you’ll learn about in college.)


Mr. Fahrenheit, way back when (18th century) created a scale using a mercury thermometer to measure temperature. He marked 0° as the temperature ice melts in a tub of salt. (Ice melts at lower temperatures when it sits in salt. This is why we salt our driveways to get rid of ice). To standardize the higher point of his scale, he used the body temperature of his wife, 96°.


As you can tell, this wasn’t the most precise or useful measuring device. I can just imagine Mr. Fahrenheit, “Hmmm, something cold…something cold. I got it! Ice in salt. Good, okay there’s zero, excellent. Now, for something hot. Ummm, my wife! She always feels warm. Perfect, 96°. ” I hope he never tried to make a thermometer when she had a fever.


Just kidding, I’m sure he was very precise and careful, but it does seem kind of weird. Over time, the scale was made more precise and today body temperature is usually around 98.6°F.


Later, (still 18th century) Mr. Celsius came along and created his scale. He decided that he was going to use water as his standard. He chose the temperature that water freezes at as his 0° mark. He chose the temperature that water boils at as his 100° mark. From there, he put in 100 evenly spaced lines and a thermometer was born.


Last but not least Mr. Kelvin came along and wanted to create another scale. He said, I want my zero to be ZERO! So he chose absolute zero to be the zero on his scale.


Absolute zero is the theoretical temperature where molecules and atoms stop moving. They do not vibrate, jiggle or anything at absolute zero. In Celsius, absolute zero is -273 ° C. In Fahrenheit, absolute zero is -459°F (or 0°R). It doesn’t get colder than that!


As you can see, creating the temperature scales was really rather arbitrary:


“I think 0° is when water freezes with salt.”
“I think it’s just when water freezes.”
“Oh, yea, well I think it’s when atoms stop!”


Many of our measuring systems started rather arbitrarily and then, due to standardization over time, became the systems we use today. So that’s how temperature is measured, but what is temperature measuring?


Temperature is measuring thermal energy which is how fast the molecules in something are vibrating and moving. The higher the temperature something has, the faster the molecules are moving. Water at 34°F has molecules moving much more slowly than water at 150°F. Temperature is really a molecular speedometer.


Let’s make a quick thermometer so you can see how a thermometer actually works:


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Hygrometer

Wednesday June 29, 2011

Hygrometers measure how much water is in the air, called humidity. If it's raining, it's 100% humidity. Deserts and arid climates have low humidity and dry skin. Humidity is very hard to measure accurately, but scientists have figured out ways to measure how much moisture is absorbed by measuring the change in temperature (as with a sling psychrometer), pressure, or change in electrical resistance (most common).

The dewpoint is the temperature when moist air hits the water vapor saturation point. If the temperature goes below this point, the water in the air will condense and you have fog. Pilots look for temperature and dewpoint in their weather reports to tell them if the airport is clear, or if it''s going to be 'socked in'. If the temperature stays above the dewpoint, then the airport will be clear enough to land by sight. However, if the temperature falls below the dewpoint, then they need to land by instruments, and this takes preparation ahead of time.

A sling psychrometer uses two thermometers (image above), side by side. By keeping one thermometer wet and the other dry, you can figure out the humidity using a humidity chart. Such as the one on page two of this document. The psychrometer works because it measures wet-bulb and dry-bulb temperatures by slinging the thermometers around your head. While this sounds like an odd thing to do, there's a little sock on the bottom end of one of the thermometers which gets dipped in water. When air flows over the wet sock, it measures the evaporation temperature, which is lower than the ambient temperature, measured by the dry thermometer.

Scientists use the difference between these two to figure out the relative humidity. For example, when there's no difference between the two, it's raining (which is 100% humidity). But when there's a 9oC temperature difference between wet and dry bulb, the relative humidity is 44%. If there's 18oC difference, then it's only 5% humidity.

You can even make your own by taping two identical thermometers to cardboard, leaving the ends exposed to the air. Wrap a wet piece of cloth or tissue around the end of one and use a fan to blow across both to see the temperature difference!

One of the most precise are chilled mirror dewpoint hygrometers, which uses a chilled mirror to detect condensation on the mirror's surface. The mirror's temperature is controlled to match the evaporation and condensation points of the water, and scientists use this temperature to figure out the humidity.

We're going to make a very simple hygrometer so you get the hand of how humidity can change daily. Be sure to check this instrument right before it rains. This is a good instrument to read once a day and log it in your weather data book.

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Anemometer

Wednesday June 29, 2011

Most weather stations have anemometers to measure wind speed or wind pressure. The kind of anemometer we’re going to make is the same one invented back in 1846 that measures wind speed. Most anemometers use three cups, which is not only more accurate but also responds to wind gusts more quickly than a four-cup model.


Some anemometers also have an aerovane attached, which enables scientists to get both speed and direction information. It looks like an airplane without wings – with a propeller at the front and a vane at the back.


Other amemometers don’t have any moving parts – instead they measure the resistance of a very short, thin piece of tungsten wire. (Resistance is how much a substance resists the flow of electrical current. Copper has a low electrical resistance, whereas rubber has a very high resistance.) Resistance changes with the material’s temperature, so the tungsten wire is heated and placed in the airflow. The wind flowing over the wire cools it down and increases the resistance of the wire, and scientists can figure out the wind speed.


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Barometer

Wednesday June 29, 2011
French physicist Blaise Pascal. He developed work on natural and applied sciences as well being a skilled mathematician and religious philosopher.
French physicist Blaise Pascal. He developed work on natural and applied sciences as well being a skilled mathematician and religious philosopher.

A barometer uses either a gas (like air) or a liquid (like water or mercury) to measure pressure of the atmosphere. Scientists use barometers a lot when they predict the weather, because it’s usually a very accurate way to predict quick changes in the weather.


Barometers have been around for centuries – the first one was in the 1640s!


At any given momen, you can tell how high you are above sea level by measure the pressure of the air. If you measure the pressure at sea level using a barometer, and then go up a thousand feet in an airplane, it will always indicate exactly 3.6 kPa lower than it did at sea level.


Scientists measure pressure in “kPa” which stands for “kilo-Pascals”. The standard pressure is 101.3 kPa at sea level, and 97.7 kPa 1,000 feet above sea level. In fact, every thousand feet you go up, pressure decreases by 4%. In airplanes, pilots use this fact to tell how high they are. For 2,000 feet, the standard pressure will be 94.2 kPa. However, if you’re in a low front, the sea level pressure reading might be 99.8 kPa, but 1000 feet up it will always read 3.6 kPa lower, or 96.2 kPa.


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Rain Gauge

Wednesday June 29, 2011

Also known as an udometer or pluviometer or ombrometer, or just plan old ‘rain cup’, this device will let you know how much water came down from the skies. Folks in India used bowls to record rainfall and used to estimate how many crops they would grow and thus how much tax to collect!


These devices reports in “millimeters of rain” or “”centimeters of rain” or even inches of rain”.  Sometimes a weather station will collect the rain and send in a sample for testing levels of pollutants.


While collecting rain may seem simple and straightforward, it does have its challenges! Imagine trying to collect rainfall in high wind areas, like during a hurricane. There are other problems, like trying to detect tiny amounts of rainfall, which either stick to the side of the container or evaporate before they can be read on the instrument. And what happens if it rains and then the temperature drops below freezing, before you’ve had a chance to read your gauge? Rain gauges can also get clogged by snow, leaves, and bugs, not to mention used as a water source for birds.


So what’s a scientist to do?


Press onward, like all great scientists! And invent a type of rain gauge that will work for your area. We’re going to make a standard cylinder-type rain gauge, but I am sure you can figure out how to modify it into a weighing precipitation type (where you weigh the amount in the bottle instead of reading a scale on the side), or a tipping bucket type (where a funnel channels the rain to a see-saw that tips when it gets full with a set amount of water) , or even a buried-pit bucket (to keep the animals out).
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Fire inside of an Orange

Sunday June 26, 2011

A combustion reaction gives off energy, usually in the form of heat and light.  The reaction itself includes oxygen combining with another compound to form water, carbon dioxide, and other products.


A campfire is an example of wood and oxygen combining to create ash, smoke, and other gases. Here’s the reaction for the burning of methane (CH4) which gives carbon dioxide (CO2) and water (H2O):


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Fast Ferry

Tuesday June 14, 2011

The ferryboat was one of the ways folks got from island to island. Usually ferries make quick, short trips from one spot to another, picking up cars, people, or packages and transporting them across the water. In Venice, you’ll hear the ferry also referred to as the “water bus” or “water taxi”.  Ferries that travel longer distances usually transport cars and trucks.


If you live in a waterside city or group of small islands, then the ferry is probably in your daily routine, because they are much cheaper than building complicated bridges or underwater tunnels.


Some ferries don’t have a “front” and “back”, but are double-ended and completely reversible, which allows them to shuttle back and forth across short distances without turning around. You’ll find these ferries in Australia, British Colombia, and Washington state.


There are many different types of ferries, including hovercraft, hydrofoils, and catamaran. Hydrofoils (shown in the image above) have special “wings” attached to the bottom of the boat that actually lift the boat out of the water when the speed increases. The special wing is designed to work in water and generate enough lift to move the massive boat out of the water so only a small part of the wing remains in the water to minimize friction (drag) force on the boat. With less friction, the boat can go even faster!


We’re going to make a simple ferry that works in the pool or bathtub. Don’t forget to add a remote control with extra-long wires!


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Two Versions of the Catamaran

Tuesday June 14, 2011

Catamarans are boats with two or more hulls that are strapped together and move by either wind power (using sails) or engine power. They are one of the first boats humans ever floated in. Catamarans are used when speed and large payloads are needed: their interesting geometric design (their balance is based on geometry, not weight) allows them to glide through the water with lower friction and carry more than single-hulled boats.


We’re going to create two different versions of the catamaran, mainly depending on how many water bottles you have available. Put these in a swimming pool and watch them zoom!
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Brushbot

Tuesday June 14, 2011

This robot as a BIG version of the tiny Bristlebot robot. Using an eccentric drive motor, this robot will show you how a cell phone vibrates by using an off-center weight being slung around by a motor. We built these types of robots in all sizes: from tiny toothbrush versions all the way to large commercial-sized sweeper brooms.


This project is just the right size to give you a fun robot that really works. It’s lightweight enough so you don’t have to use large, expensive motors or power supplies and worry about high voltage… so enjoy!


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Amphibious Robot

Tuesday June 14, 2011

Amphibious vehicles is a craft which travels on both land and water. And it doesn't need to be limited to just cars. There are amphibious bicycles, buses, and RVs. Hovercraft are amphibious, too!

Amphibious crafts started back in the 1800s as steam-powered barges. In the 1950s, the German Schimmwagen was a small jeep that could travel in water as well as on land. The most popular amphibious vehicle on the market is the 1960 Amphibicar (photo shown left) and later the Gibbs Aquada.

The secret to making an amphibious vehicle is this: it must be designed so it floats in water (it must be watertight and buoyant) and robust enough to travel on land. Many amphibious creations either leaked, sank, or never made it off the drawing board. But that's what being a scientist is all about: coming up with an overall goal and figuring out a way to overcome the problems faced along the way.

We're going to build our own version using items like foam blocks and hobby motors. Are you ready?
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Amphibious Robot Vehicle with Transmission

Tuesday June 14, 2011

The image here is the 2003 Gibbs Aqauda at full speed in deep water! It looks like it’s just skipping along the surface, doesn’t it?


The Gibbs company uses auto, marine, and propulsion technologies to build water-land vehicles used mostly by the military. But wouldn’t it save time to cut through the traffic on the bridge if you could skim through the water?


One of the main issues with amphibious vehicles is that they are painfully slow – both in the water and on land. (Although the 2003 Aquada gets up to 30 mph in water.)


The other issue is safety – the lift from the bow on a boat is needed to avoid plunging, but on a car you don’t want the front end to lift at high speeds.  Also a boat distributes the load evenly across the hull while a car has  concentrated loads where the suspension is attached to the frame.


The Aquada car uses a 160 hp engine for land and a compact jet that produces 2,000 pounds of thrust. It broke the record for crossing the English Channel by four whole hours (third image below with the orange boat in the background).


And if the car goes fast enough, you can pull a waterskier.


The Gibbs company has also invented the Humdinga, which is for military use, as it has four-wheel drive at can cruise at 40 mph on water, as well as the Quadski, which travels at 50 mph on land or sea.


We’re going to build our own model, though not with a jet engine. We’re going to use a motor, wheels, floats, and wires to build a real working model you can use in the tub tonight. Our model is also going to have a transmission that will enable you to get  two different speeds using very simple materials. Are you ready? Here’s what you need to do:


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Physics Shopping List

Saturday June 11, 2011

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


This particular shopping list has many different projects on it, so we’ve broken the list into sections based on the projects. For example, the roller coaster activities are all in one area, the weather station in another, etc. You might want to view the videos before gathering your supplies.


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Materials

Materials for Sonic Vibrations Experiments


  • 3 popsicle sticks (tongue depressor size)
  • 2 index cards
  • Scissors, tape, hot glue gun
  • 2 film canisters (or plastic snap-lid M&M containers)
  • Straw
  • Three 7-9” balloons
  • 2 water balloons
  • 3’ string
  • Rubber bands (at least two are ¼” thick)
  • Disposable cup (plastic, foam, or paper)
  • Hexnut (1/4” or smaller)
  • Razor or drill to make holes in the film canister
  • Scissors, tape

Weather Station Project


  • 2 popsicle sticks
  • 1 long strand of hair
  • 1 index card
  • 12” piece of cardboard (scraps are great)
  • 4 foam cups
  • 2 popsicle sticks
  • 1 pencil with built-in eraser on top
  • 2 tacks
  • 1 nickel
  • Scissors
  • Tape
  • 7-9” balloon
  • Water glass
  • Straw or wooden skewer
  • Empty water bottle
  • Funnel
  • Rubbing alcohol
  • Clay
  • Straw
  • Food coloring
  • Optional: Sunprint Paper and soup can

Magic Tricks


  • Dollar bill
  • 2 small paperclips
  • 6’ of rope
  • 1 rubber band
  • 1 toilet paper tube
  • 1 egg (hard boiled) OR ball that sits on the end of the toilet paper tube without falling in
  • Aluminum pie plate or plastic dish (something not breakable)
  • Broom handle or ruler
  • Shoe with laces
  • Four bracelets (optional)

Materials for Roller Coasters Experiments


  • ¾” foam pipe insulation
  • Masking tape
  • A handful of marbles
  • Chairs and tables

Materials for Clothespin Catapult Project


  • Popsicle sticks
  • Plastic spoon
  • 3 rubber bands
  • Wood clothespin
  • Straw
  • Wood dowel that fits inside the straw
  • Scissors
  • Hot glue gun

Materials for Mousetrap RaceCar


  • Mousetrap (NOT a rat trap)
  • Foam block or piece of cardboard
  • Four old CDs
  • Thin string or fishing line
  • Wood dowel or long, straight piece from a wire coat hanger (use pliers to straighten it)
  • Straw
  • Two wood skewers (that fit inside straw)
  • Hot glue gun
  • Duct tape
  • Scissors
  • Four caps to water bottles
  • Drill
  • Razor with adult help

Introduction to Slime Science

Tuesday May 31, 2011

When you think of slime, do you imagine slugs, snails, and puppy kisses? Or does the science fiction film The Blob come to mind? Any way you picture it, slime is definitely slippery, slithery, and just plain icky — and a perfect forum for learning real science.


But which ingredients work in making a truly slimy concoction, and why do they work? Let’s take a closer look!


Imagine a plate of spaghetti. The noodles slide around and don’t clump together, just like the long chains of molecules (called polymers) that make up slime. They slide around without getting tangled up. The pasta by itself (fresh from the boiling water) doesn’t hold together until you put the sauce on. Slime works the same way. Long, spaghetti-like chains of molecules don’t clump together until you add the sauce … until you add something to cross-link the molecule strands together.


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Chemistry Shopping List

Tuesday May 31, 2011

This is a Bonus Lab, which means that the experiments in this section require adult help (we’re working with fire in several of them), and/or the materials are more expensive and hard to find.


Use the experiments in this section for kids wanting to go even further and deeper into the subject. Since these are more involved, be sure to browse through the videos for these experiments first before purchasing materials for these additional labs.


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


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Materials for Kitchen Chemistry


  • Milk (whole or lowfat)
  • Food dye
  • Dish soap
  • Water and Ice
  • Bowl
  • Drinking glass
  • Egg (two hardboiled)
  • Vinegar
  • Salt
  • Hydrogen peroxide
  • Yeast (the kind you use for bread)
  • Empty water or soda bottle (1 liter size)
  • Cornstarch (a couple tablespoons)
  • Iodine (from the pharmacy)
  • Fresh citrus for testing
  • Popsicle sticks or disposable plastic spoon
  • Acetone (fingernail polish remover)
  • Styrofoam cup

Materials for Bubblology


  • Straws
  • String
  • Paper clips (small)
  • 2L soda bottles
  • Plastic berry basket
  • Wire coat hangers (bendable)
  • Thick rubber bands
  • Stiff card stock (or paper)
  • Plate or cookie sheet
  • Balloon
  • 6 feet of loosely woven inch-wide fabric trim (lace)
  • Scissors
  • Water (distilled if you have it)
  • 1-2 cups clear Ivory dish soap OR liquid Joy Ultra OR green Dawn
  • Buckets to hold your soap solution
  • Glycerin (check your pharmacy)

Materials for Acids and Bases


  • pH paper OR a head of red cabbage and paper towels/coffee filter
  • Juice or fruit (anything you have will work)

Materials for Instant Crystal Sculptures


  • Reusable hand warmer (the kind with a metal disc inside you flex to activate the sodium acetate)
  • Disposable plate
  • Scissors

Materials for Liquid Magnets


  • Vegetable cooking oil (1/4 cup)
  • Old toner or liquid toner
  • Magnet
  • Small soda bottle with cap

Materials for Volcanoes


  • 9 cups flour
  • 3 cups dirt
  • 4 cups salt
  • 1 cup sand
  • Water
  • Disposable roasting pan
  • 4 cups baking soda
  • 4 cups distilled white vinegar
  • 2 empty water bottles
  • 1 cup liquid dish soap
  • 1 cup aluminum sulfate (check gardening section)
  • 18” length of clear, flexible tubing (any diameter between ¼” – ½”)
  • Red food dye (optional)

Materials for Water Purification Experiment


  • coffee with grinds mixed back in stored in an old plastic water bottle
  • popsicle sticks for mixing
  • activated carbon granules (from a fish tank supply store)
  • clean water
  • funnel
  • two cotton balls
  • three small disposable cups (clear is best so you can see what you’re doing)
  • medicine dropper or syringe (no needle)
  • aluminum sulfate (AKA alum from the spice section)
  • calcium hydroxide (AKA lime) from the gardening section. Note: keep this chemical packed away, as the dust is toxic and should not be inhaled.

Materials for Slime Science


  • yellow highlighter pen
  • guar gum (check health food stores)
  • sodium tetraborate (AKA: borax)
  • liquid starch (check the laundry aisle for Vano or Sta-Flo)
  • cornstarch (about 2 cups)
  • white glue
  • clear glue
  • disposable cups
  • popsicle sticks
  • measuring spoons
  • water
  • sugar (about 1 cup)
  • goggles
  • PVA (polyvinyl alcohol) (optional)
  • food dye (optional)

Materials for Bouncy Balls


  • Sodium Silicate (from Unit 3)
  • Ethyl Alcohol (check your pharmacy)
  • 2 disposable cups (don’t use your kitchen glassware, as you’ll never get it clean again)
  • 2 Popsicle sticks (again, use something disposable to stir with)
  • Gloves for your hands
  • Goggles for your face

Materials for Burning Money


  • Shallow baking dish
  • Tongs
  • Rubbing Isopropyl Alcohol (50-91%)
  • Dollar bill
  • Fire extinguisher with adult help

Materials for Football Ice Cream:


  • 1 quart whole milk (do not substitute, unless your child has a milk allergy, use soy or almond milk)
  • 1 pint heavy cream (do not substitute, unless your child has a milk allergy, then skip)
  • 1 cup sugar (or other sweetener)
  • 1 tsp vanilla (use non-alcohol kind)
  • Rock salt (use table salt if you can’t find it)
  • Lots of ice
  • Freezer-grade zipper-style bags (you’ll need quart and gallon sizes)

Materials for Colored Campfires & Spectrometer


  • Old ceramic or metal pot with lid
  • Heat-proof surface
  • BBQ lighter with adult help
  • Methanol
  • Popsicle sticks

Select the chemical additive you want:


  • Boric acid
  • Sodium tetraborate (borax)
  • Epsom salts (magnesium sulfate)
  • Regular table salt (sodium chloride)
  • Salt substitute (potassium chloride)
  • Ice Melt or Dri-Ez (pure calcium chloride)

To build the spectrometer:


  • Cardboard box (ours is 10″ x 5″ x 5″, but anything close to this will work fine)
  • Diffraction grating (you can order a sheet here)
  • Two razor blades (with adult help)
  • Masking tape
  • Ruler
  • Photocopy of a cm (centimeter) ruler (or sketch a line with 1 through 10 cm markings on it, about 4cm wide)

Materials for Iodine Rainbow


  • Iodine (clear, non-ammonia from the pharmacy)
  • Hydrogen peroxide (3% solution)
  • Vinegar (distilled white is best)
  • Cornstarch (tiny pinch) or one starch packing peanut
  • Water
  • Sodium Thiosulfate
  • Sodium Carbonate (AKA: “washing soda“)
  • Phenolphthalein (keep this out of reach of kids)
  • 6 disposable cups
  • 6 Popsicle sticks
  • Gloves for your hands
  • Goggles for your face

Roller Coasters Game Plan

Tuesday May 31, 2011

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Objective You will learn about force, acceleration, velocity, and what scientist really mean when they say, “Try it again…and again…and again… until you get the result you want.” This lab uses the Iteration Technique to solving a problem, which is different than the Scientific Method, and actually much more widely used by engineers in the science field.


About the Experiment This lab is an excellent opportunity for kids to practice their resilience, because we guarantee this experiment will not work the first several times they try it.  While you can certainly help the kids out, it’s important that you help them figure it out on their own.  You can do this by asking questions instead of rushing in to solve their problems.  For instance, when the marble flies off the track, you can step back and say:


“Hmmm… did the marble go to fast or too slow?”


“Where did it fly off?”


“Wow – I’ll bet you didn’t expect that to happen.  Now what are you going to try?”


Become their biggest fan by cheering them on, encouraging them to make mistakes, and try something new (even if they aren’t sure if it will work out). One of the greatest gifts you can give your child is the expectation of their success.


The How and Why To make the roller coasters, you’ll need foam pipe insulation, which is sold by the six-foot increments at the hardware store.  You’ll be slicing them in half lengthwise, so each piece makes twelve feet of track.  It comes in all sizes, so bring your marbles when you select the size.  The ¾” size fits most marbles, but if you’re using ball bearings or shooter marbles, try those out at the store.  (At the very least you’ll get smiles and interest from the hardware store sales people.) Cut most of the track lengthwise (the hard way) with scissors.  You’ll find it is already sliced on one side, so this makes your task easier.  Leave a few pieces uncut to become “tunnels” for later roller coasters.


The next step is to join your track together before adding all the features like loops and curves.  Join two tracks together in butt-joint fashion and press a piece of masking tape lengthwise along both the inside and the underside of the track.  A third piece of tape should go around the entire joint circumferentially.  Make this connection as smooth as possible, as your high-speed marble roller coaster will tend to fly off the track at the slightest bump.


Loops Swing the track around in a complete circle and attach the outside of the track to chairs, table legs, and hard floors with tape to secure in place.  Loops take a bit of speed to make it through, so have your partner hold it while you test it out before taping.  Start with smaller loops and increase in size to match your entrance velocity into the loop.  Loops can be used to slow a marble down if speed is a problem.


Camel-Backs Make a hill out of track in an upside-down U-shape.  Good for show, especially if you get the hill height just right so the marble comes off the track slightly, then back on without missing a beat.


Whirly-Birds Take a loop and make it horizontal.  Great around poles and posts, but just keep the bank angle steep enough and the marble speed fast enough so it doesn’t fly off track.


Corkscrew Start with a basic loop, then spread apart the entrance and exit points.  The further apart they get, the more fun it becomes.  Corkscrews usually require more speed than loops of the same size.


Jump Track A major show-off feature that requires very rigid entrance and exit points on the track.  Use a lot of tape and incline the entrance (end of the track) slightly while declining the exit (beginning of new track piece).


Pretzel The cream of the crop in maneuvers!  Make a very loose knot that resembles a pretzel.  Bank angles and speed are the most critical, with rigid track positioning a close second.  If you’re having trouble, make the pretzel smaller and try again.  You can bank the track at any angle because the foam is so soft.  Use lots of tape and a firm surface (bookcases, chairs, etc).


Troubleshooting Marbles will fly everywhere, so make sure you have a lot of extras!  If your marble is not following your track, look very carefully for the point of departure – where it flies off.


  • Does the track change position with the weight of the marble, making it fly off course?  Make the track more rigid by taping it to a surface.
  • Is the marble jumping over the track wall?  Increase your bank angle (the amount of twist the track makes along its length).
  • Does your marble just fall out of the loop?  Increase your marble speed by starting at a higher position.  When all else fails and your marble still won’t stay on the track, make it a tunnel section by taping another piece on top the main track.  Spiral-wrap the tape along the length of both pieces to secure them together.

Why does the marble stick to the track? The faster the marble travels in a loop, the more it sticks to the track. This is the same pancake feeling you get when your body gets pulled into a tight turn (whether in a car or on a roller coaster). The faster and tighter the turn, the more the “pancake feeling”. That pancake thing is called acceleration. You’re feeling a pull away from the center of the loop, which will vary depending on how fast you are going, called centrifugal force.


That’s usually enough for kids.  But if you really want to be thoroughly confused, keep reading about how centripetal and centrifugal forces are NOT the same thing:


What about centripetal force? Ah, yes… these two words constantly throw college students into a frenzy, partially because there is no clear definition in most textbooks. As I best understand it, centripetal (translation = “center-seeking”) force is the force needed to keep an object following a curved path. Remember how objects will travel in a straight line unless they bump into something or have another force acting on it (gravity, drag force, etc.)? Well, when you swing a bucket of water around, the force to keep the bucket of water swinging in a curved arc is the centripetal force, which can be felt in the tension experienced by the handle (or your arm, in our case). Swinging an object around on a string will cause the rope to undergo tension (centripetal force), and if your rope isn’t strong enough, it will snap and break, sending the mass flying off in a tangent (straight) line until gravity and drag force pull the object to a stop. This force is proportional to the square of the speed… the faster you swing the object, the higher the force.


Centrifugal (translation = “center-fleeing”) force has two different definitions, which also causes confusion. The inertial centrifugal force is the most widely referred to, and is purely mathematical, having to do with calculating kinetic forces using reference frames, and is used with Newton’s laws of motion. It’s often referred to as the ‘fictitious force’.


The other kind, reactive centrifugal force, happens when objects move in a curved path. This force is actually the same magnitude as centripetal force, but in the opposite direction, and you can think of it as the reaction force to the centripetal force. Think of how you stand on the Earth… your weight pushes down on the Earth, and a reaction force (called the “normal” force) pushes up in reaction to your weight, keeping you from falling to the center of the Earth. A centrifugal governor (spinning masses that regulate the speed of an engine) and a centrifugal clutch (spinning disk with two masses separated by a spring inside) are examples of this kind of force in action.


One more example: Imagine driving a car along a banked turn. The road exerts a centripetal force on the car, keeping the car moving in a curved path (the “banked” turn). If you neglected to buckle your seat belt and the seats have a fresh coat of Armor-All (making them slippery), then as the car turns along the banked curve, you get “shoved” toward the door. But who pushed you? No one – your body wanted to continue in a straight line but the car keeps moving in your path, turning your body in a curve. The push of your weight on the door is the reactive centrifugal force, and the car pushing on you is the centripetal force.


What about the fictitious (inertial) centrifugal force? Well, if you imagine being inside the car as it is banking with the windows blacked out, you suddenly feel a magical ‘push’ toward the door away from the center of the bend. This “push” is the fictitious force invoked because the car’s motion and acceleration is hidden from you (the observer) in the reference frame moving within the car.


Sonic Vibes Game Plan

Tuesday May 31, 2011

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Objective This noisy lab lets you experiment with the idea that sound is a vibration.  By making over a dozen different noisemakers, you can explore how to change the sound speed and use everyday materials to annoy your parents.


About the Experiments Instead of starting with an explanation of how sound works, mystify your kids with it instead by picking one of the experiments that you know your kids will like. After they’ve build the project (you might want ear muffs for this lab), you can start asking them how they think it works.  Give them the opportunity to figure it out by changing different things on their noisemaker (stretch the rubber band, increase the tube length, etc) to allow them a chance to hone their skills at figuring things out.


The How and Why Explanation Sound is everywhere.  It can travel through solids, liquids, and gases, but it does so at different speeds.  It can rustle through trees at 770 MPH (miles per hour), echo through the ocean at 3,270 MPH, and resonate through solid rock at 8,600 MPH.  Sound is made by things vibrating back and forth, whether it’s a guitar string, drum head, or clarinet. The back and forth motion of an object (like the drum head) creates a sound wave in the air that looks a lot like a ripple in a pond after you throw a rock in.  It radiates outward, vibrating it’s neighboring air molecules until they are moving around, too.  This chain reaction keeps happening until it reaches your ears, where your “sound detectors” pick up the vibration and works with your brain to turn it into sound.


Your voice is a vibration, and you can feel it when you place a hand on your throat when you speak.  As long as there are molecules around, sound will be traveling though them by smacking into each other.  That’s why if you put an alarm clock inside a glass jar and remove the air, there’s no sound from the clock.  There’s nothing to transfer the vibrational energy to – nothing to smack into to transfer the sound. It’s like trying to grab hold of fog – there’s nothing to hold on to.


Sound can change according to the speed at which it travels.  Another word for sound speed is pitch.  When the sound speed slows, the pitch lowers.  With clarinet reeds, it’s high.  Guitar strings can do both, as they are adjustable. If you look carefully, you can actually see the low pitch strings vibrate back and forth, but the high pitch strings move so quickly it’s hard to see. But you can detect the effects of both with your ears.


The range of your ears is about 20 – 20,000 Hz (cycles per second). Bats and dogs can hear a lot higher than we can. The image (right) is a real picture of an aircraft as it breaks the sound barrier – meaning that the aircraft is passing the speed that sounds travels at (about 700 mph).  The white cloud you see in the photo is related to the shock waves that are forming around the craft as it moves into supersonic speeds. You can think of a shock wave as big pressure front, which creates clouds. In this photo, the pressure from the shock waves is condensing the water vapor in the air.


There are lots of things on earth that break the sound barrier – bullets and bullwhips, for example.  The loud crack from a whip is the tip zipping faster than the speed of sound.  Your air horn is a loud example of how sound waves travel through the air.


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. Sound travels fastest in (a) air (b) the ocean (c) rock (d) outer space
  2. The hornet works because (a) the rubber band vibrates when the wind flies over it       (b) you’ve trapped a real wasp in there (c) the string vibrates when you twirl it around (d) the card vibrates with the wind
  3. An old-fashioned telephone made from cups and string work great because (a) no batteries are required (b) the cup vibrates (c) the string vibrates (d) your voice vibrates (e) all of the above
  4. Knowing what you do know about sound and cups, which way do you think you would hold a cup up to your ear (open end or closed end?) to hear the conversation on the other side of a door?
  5. When you replaced the string with a slinky, why can’t you talk or hear voices through it anymore?  What can you hear instead?
  6. What would you use to completely block out the sound of an alarm clock?
  7. Does the pitch increase or decrease when you fill a glass bottle while tapping the side with a fork?
  8. List out the different kinds of strings tested with the String Test, and number them in order of best to worst.

Rocket Car

Sunday May 29, 2011

Newton's Third Law states that all forces come in pairs. When you push against the wall, the wall pushes back against you with an equal amount of force (or push). When a rocket fires, the rocket moves forward as the exhaust gases move in the opposite direction. An inflated balloon will zip through the air as the air escapes. For every action there is an equal and opposite reaction.

If you were to fart in space, what do you think would happen (before it froze)? You would move in the opposite direction!

This rocket car uses high pressure on the inside to blow a weight out the back (the neoprene stopper) and propel itself forward.

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Stomp Rockets

Sunday May 29, 2011
These rockets use air pressure to launch your lightweight rocket skyward. Using simple materials, you'll be able to make your launcher in minutes and as many rockets as you want. The first time I flew these, they got stuck on the roof, so be prepared with a few extras just in case. Please login or register to read the rest of this content.


Optics, Fire, and Eyes

Sunday May 29, 2011

If you’ve never done this experiment, you have to give it a try! This activity will show you the REAL reason that you should never look at the sun through anything that has lenses in it.


Because this activity involves fire, make sure you do this on a flame-proof surface and not your dining room table! Good choices are your driveway, cement parking lot, the concrete sidewalk, or a large piece of ceramic tile.  Don’t do this experiment in your hand, or you’re in for a hot, nasty surprise.


As with all experiments involving fire, flames, and so forth, do this with adult help (you’ll probably find they want to do this with you!) and keep your fire extinguisher handy.


Materials:


  • sunlight
  • dead leaf
  • magnifying glass
  • fire extinguisher
  • adult help

Here’s what you need to do:


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Learn How to Solder and Build a Police Siren

Sunday October 3, 2010

This project is for advanced students.


This is two projects in one.  No one starts out soldering well (I know I didn’t).  So, we’re going to start out by just practicing soldering parts onto a PCB that doesn’t do anything.  No point in making mistakes on a real project and possibly ruining it.


Once you have the hang of soldering, we’ll  make a working siren.  Just follow along with the steps in the video.  By the way, the siren circuit isn’t that different from the Audible Light Probe.  It makes sound in a similar way, and is just wired to make different frequencies take turns by charging capacitors at different rates.


To make this project, you’ll need to get a Police Siren Kit. You’ll also need a soldering iron with a stand and some basic tools (scissors, hot glue gun, drill, wire strippers, pliers, screwdriver). (Need a recommendation for a soldering iron? Click here.)


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Wireless FM Transmitter (the ‘Bug’)

Sunday October 3, 2010

fm-xmitterThis project is for advanced students. Make sure you’ve completed the Police Siren project first!


This is a really cool one.  You’re actually going to build a miniature radio station.  You can broadcast your voice or music to a regular FM radio.  It just has a very short range (about 100 feet, or 30 meters).


It’s just a bit more complicated than the siren, and it will need some “tuning” when you’re done with it.  Take your time with this one and have fun.


To make this project, you’ll need the Wireless FM Transmitter kit, your soldering equipment, and basic tools (pliers, wire strippers, scissors, etc.)


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Door Knob Touch Alarm

Sunday October 3, 2010

dooralarmThis project is for advanced students. Make sure you’ve completed the Police Siren project first!


This is my favorite burglar alarm because it’s innocent-looking, hair-triggered, and completely obnoxious. Here’s what happens: after you build this circuit, you hang the wire loop around a metal doorknob, add the battery, and stand back. When an unsuspecting thief comes into your room, the alarm sounds as soon as they touch the other side of the door knob… and presto! You caught your burglar.


This circuit uses an IC (integrated circuit) called the LM324, which is a quad op-amp (operational amplifier), which produces a voltage that many times larger than the voltage difference between the inputs.  Created in 1972, these low-power op-amps are actually four op-amps packaged into one. Although they are commonplace today in many electronic devices, they first started out in the 1940s as vacuum-tube devices at Bell Labs.


Are you ready to build a super-cool burglar alarm? To make this project, you’ll need to Door Knob Touch Alarm Kit, soldering equipment, and basic tools (scissors, hot glue gun, drill, wire strippers, pliers, screwdriver). (Don’t know how to solder yet? Click here for a lesson!)


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Simple Microscope & Telescope

Wednesday September 1, 2010

Did you know you can create a compound microscope and a refractor telescope using the same materials? It’s all in how you use them to bend the light. These two experiments cover the fundamental basics of how two double-convex lenses can be used to make objects appear larger when right up close or farther away.


Things like lenses and mirrors can bend and bounce light to make interesting things, like compound microscopes and reflector telescopes. Telescopes magnify the appearance of some distant objects in the sky, including the moon and the planets. The number of stars that can be seen through telescopes is dramatically greater than can be seen by the unaided eye.


Materials


  • A window
  • Dollar bill
  • Penny
  • Two hand-held magnifying lenses
  • Ruler
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Introduction to Magic Tricks

Wednesday June 30, 2010

If you’ve never made a paperclips jump together and link up by themselves, turned water into ink, or made metal rings pass through solid rope, you’re missing out. Big time.  We’re going to show you our set of incredible magic-show-style tricks that will make you truly amazing.


But, there is something you should know about magic…


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Magic Trick: Dollar Magic

Wednesday June 30, 2010

This trick is one of my favorites, because it's super-easy and quick... you'll have a hard time describing to yourself how it even happened. Most scientists can't explain it either. Are you ready?

Materials: dollar bill, two paperclips, and a rubber band.

Here's what you do:

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Magic Trick: Tied Up in Knots

Wednesday June 30, 2010

This particular trick kept me tied up for hours as a kid. I was so determined to figure this out that I eventually had a rope-impression rubbed into my skin when I finally did slide out. I’ll bet it doesn’t take you nearly as long, and you can substitute bracelets for the rope to make it more comfortable as you work. You need two kids for this trick to work. And a camera to capture the moment.


Materials: 6 feet of rope, two kids, and 4 bracelets (optional)


Here’s what you do:
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PVA Slime

Wednesday June 30, 2010

Instead of using glue as a polymer (as in the slime recipes above), we're going to use PVA (polyvinyl alcohol). Most liquids are unconnected molecules bouncing around. Monomers (single molecules) flow very easily and don't clump together. When you link up monomers into longer segments, you form polymers (long chains of molecules).

Polymers don't flow very easily at all - they tend to get tangled up until you add the cross-linking agent, which buddies up the different segments of the molecule chains together into a climbing-rope design.

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Non-Messy Squishy Slime

Wednesday June 30, 2010

Squishy Slime Mix 1 cup sugar, 12 cups water, and 3 cups cornstarch in a saucepan. Stir constantly over medium heat until thickened, about 5 minutes. Place a glop in each of several bowls along with drops of food coloring in each. Place a dollop of each color into a plastic sandwich bad and zip it shut. You can squish and squeeze without getting your hands slimy!


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Corny Slime

Wednesday June 30, 2010

Ever wonder why ketchup doesn't flow easily out of the bottle? Now you know it's because the ketchup acts just like the cornstarch-water experiment here. More examples of non-Newtonian fluids are ketchup, blood, paint, and shampoo.

We're going to whip up a batch of non-Newtonian fluid that's going to act like both a solid and a liquid.  Here's what you do:

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Bouncy Putty Slime

Wednesday June 30, 2010

The glue is a polymer, which is a long chain of molecules all hooked together like tangled noodles. When you mix the two solutions together, the water molecules start linking up the noodles together all along the length of each noodle to get more like a fishnet. Scientists call this a polymetric compound of sodium tetraborate and lactated glue. We call it bouncy putty.


Here’s what you do:


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Football Ice Cream

Wednesday June 30, 2010

Is it hot where you live in the summer? What if I gave you a recipe for making ice cream that doesn’t require an expensive ice cream maker, hours of churning, and can be made to any flavor you can dream up? (Even dairy-free if needed?)


If you’ve got a backyard full of busy kids that seem to constantly be in motion, then this is the project for you.  The best part is, you don’t have to do any of the churning work… the kids will handle it all for you!


This experiment is simple to set up (it only requires a trip to the grocery store), quick to implement, and all you need to do guard the back door armed with a hose to douse the kids before they tramp back into the house afterward.


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Colored Campfires and Rainbows

Wednesday June 30, 2010

Always have a FIRE EXTINGUISHER and ADULT HELP handy when performing fire experiments. NO EXCEPTIONS.

This video will show you how to transform the color of your flames. For a campfire, simply sprinkle the solids into your flames (make sure they are ground into a fine powder first) and you’ll see a color change. DO NOT do this experiment inside your house – the fumes given off by the chemicals are not something you want in your home!


One of the tricks to fire safety is to limit your fuel. The three elements you need for a flame are: oxygen, spark, and fuel.  To extinguish your flames, you’ll have to either wait for the fuel to run out or smother the flames to cut off the oxygen. When you limit your fuel, you add an extra level of safety to your activities and a higher rate of success to your eyebrows.


Here’s what we’re going to do: first, make your spectrometer: you can make the simple spectrometer or the more-advanced calibrated spectrometer. Next, get your chemicals together and build your campfire. Finally, use your spectrometer to view your flames.


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Sewer Slime

Wednesday June 30, 2010

Guar gum comes from the guar plant (also called the guaran plan), and people have found a lot of different and interesting uses for it.  It’s one of the primary substitutes for fat in low-fat and fat-free foods. Cooks like to  use guar gum in foods as it has 8 times the thickening power of cornstarch, so much less is needed for the recipe. Ice cream makers use it to keep ice crystals from forming inside the carton. Doctors use it as a laxative for their patients.


When we teach kids how to make slime using guar gum, they call it “fake fat” slime, mostly because it’s used in fat-free baking.  You can find guar gum in health food stores or order it online. We’re going to whip up a batch of slime using this “fake fat”. Ready?


Here’s what you do:
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Volcanoes

Wednesday June 30, 2010

If you’ve ever wanted to make your own version of a volcano that burps and spit all over the place, then this is the experiment for you.  We used to teach kids how to make genuine Fire & Flame volcanoes, but parents weren’t too happy about the shower of sparks that hit the ceiling and fireballs that shot out of the thing… so we’ve toned it down a bit to focus more on the lava flow.


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Water Purification

Wednesday June 30, 2010

Ever wonder how the water draining down your sink gets clean again? Think about it: The water you use to clean your dishes is the same water that runs through the toilet.  There is only one water pipe to the house, and that source provides water for the dishwasher, tub, sink, washing machine, toilet, fish tank, and water filter on the front of your fridge.  And there’s only one drain from your house, too!  How can you be sure what’s in the water you’re using?


This experiment will help you turn not only your coffee back into clear water, but the swamp muck from the back yard as well.  Let’s get started.
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Calibrated Spectrometer

Wednesday June 30, 2010

Ever play with a prism? When sunlight strikes the prism, it gets split into a rainbow of colors. Prisms un-mix the light into its different wavelengths (which you see as different colors). Diffraction gratings are tiny prisms stacked together.

When light passes through a diffraction grating, it splits (diffracts) the light into several beams traveling at different directions. If you’ve ever seen the ‘iridescence’ of a soap bubble, an insect shell, or on a pearl, you’ve seen nature’s diffraction gratings.

Scientist use these things to split incoming light so they can figure out what fuels a distant star is burning. When hydrogen burns, it gives off light, but not in all the colors of the rainbow, only very specific colors in red and blue. It’s like hydrogen’s own personal fingerprint, or light signature.

While this spectrometer isn't powerful enough to split starlight, it's perfect for using with the lights in your house, and even with an outdoor campfire.  Next time you're out on the town after dark, bring this with you to peek different types of lights - you'll be amazed how different they really are. You can use this spectrometer with your Colored Campfire Experiment also.

SPECIAL NOTE: This instrument is NOT for looking at the sun. Do NOT look directly at the sun. But you can point the tube at a sheet of paper that has the the sun’s reflected light on it.

Here's what you do:

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Walk On Water

Wednesday June 30, 2010

When I teach camp, the last experiment on Chemistry day is to ‘walk on water’. I present the kids with a milky-white tub full of water and a secret ingredient. I stick my hand in the tub and pull it out (slowly) so they can see it’s clearly a liquid (as it dribbles off my fingers), and the kids always gasp in surprise when I then smack it with my hand, because now it looks rock-solid.


Their challenge? To step up and across without sinking. Of course, sinking can be fun, too!


NOTE: You’ll see a tub full of water at the end of the line – this helps wash off their feet after they’re done stepping across.


Here’s what you need to do:
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Pinhole Solar Projector

Wednesday June 30, 2010

You might be curious about how to observe the sun safely without losing your eyeballs. There are many different ways to observe the sun without damaging your eyesight. In fact, the quickest and simplest way to do this is to build a super-easy pinhole camera that projects an image of the sun onto an index card for you to view.


CAUTION: DO NOT LOOK AT THE SUN THROUGH ANYTHING WITH LENSES!!


This simple activity requires only these materials:


  • tack
  • 2 index cards (any size)
  • sunlight
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Top Summer Targets for Binoculars

Wednesday June 30, 2010

Did you know you can see the moons of Jupiter and Saturn with only a pair of binoculars? During the summer, there’s really nothing better than star gazing with a pair of binoculars with your kids, and I’m going to help you hit the highlights, even if you don’t know an atom from an angström. I’ve put together a list of my favorite picks from the northern hemisphere’s summer sky. So get out your binoculars, pop the popcorn, and spend time outdoors with your kids.


Need a pair of binoculars? For kids, I recommend the $35 pair Cometron by Celestron.  They’re great for kids and beginners, and you can use them for terrestrial bird-watching as well as night-sky observing.


For adults, Orion’s 10×50 UltraViews are excellent. I personally own a set of these, and I’ve also added an L-adapter and camera tripod for longer viewing sessions.


ONLINE Stargazing!

We are going to have monthly stargazing! All you need are clear, dark skies and a group of kids! You don’t need binoculars, but they can be nice to have.


Here are star gazing videos you can watch by month:


Stargazing May 2020


Stargazing June 2020


Stargazing July 2020 (Coming soon!)


Stargazing August 2020 (Coming soon!)


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Streaming Water

Tuesday June 1, 2010

Fill the bathtub and climb in. Grab your water bottle and tack and poke several holes into the lower half the water bottle. Fill the bottle with water and cap it. Lift the bottle above the water level in the tub and untwist the cap. Water should come streaming out. Close the cap and the water streams should stop. Open the cap and when the water streams out again, can you “pinch” two streams together using your fingers?


Materials: A tack, and a plastic water bottle with cap, and bathtub


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Sneaky Bottles

Tuesday June 1, 2010

This experiment illustrates that air really does take up space! You can’t inflate the balloon inside the bottle without the holes, because it’s already full of air. When you blow into the bottle with the holes, air is allowed to leak out making room for the balloon to inflate. With the intact bottle, you run into trouble because there’s nowhere for the air already inside the bottle to go when you attempt to inflate the balloon.


You’ll need to get two balloons, one tack, and two empty water bottles.


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Squished Balloon

Tuesday June 1, 2010

Fire eats air, or in more scientific terms, the air gets used up by the flame and lowers the air pressure inside the jar. The surrounding air outside the jar is now at a higher pressure than the air inside the jar and it pushes the balloon into the jar. Remember: Higher pressure pushes!


Materials: a balloon, one empty glass jar, scrap of paper towel , matches with an adult


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Fountain Bottle

Tuesday June 1, 2010

As you blow air into the bottle, the air pressure increases inside the bottle. This higher pressure pushes on the water, which gets forced up and out the straw (and up your nose!).


Materials: small lump of clay, water, a straw, and one empty 2-liter soda bottle.


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First Flying Lesson in an Airplane

Monday May 31, 2010

If your kids are hog-wild about flying and can't seem to get enough of paper airplanes, flying kites, and rockets, here's something you can do that will last their entire lifetime.

One of the best ways to introduce kids into the world of aeronautics and aviation is to get them inside a small airplane. By having the kids actually FLY, they get a chance to interact with a real pilot, see how the airplane responds to the controls, and get a taste for what their future can really be like if they keep up their studies in aerodynamics.

We're going to learn how to fly an airplane from a certified flight instructor.  He's going to walk you through every step, from pre-flight to take-off to landing.  You'll hear the radio transmissions from other aircraft flying in the area, how the control tower directs traffic, and more.  We've used a special microphone inside the cockpit to cut down on the engine noise (which actually was rigged up to only record when it heard voice sounds), so the sound might seem different than you expected.

Are you ready?

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Bat Kite

Monday May 31, 2010
Want to build a kite in less than 5 minutes? This kite is basically a paper airplane on a string. It’s fast and easy to make. The best thing about this kite is that it needs next to no wind to get airborne, so you can simply run with it to get it up in the sky.

You'll need to get: 11”x17” sheet of paper (you can also tape two 8.5" x 11" sheets together to make this size), 10 feet of string, two donut stickers (also known as page reinforcement stickers), a stapler, and a straw.

Why does this kite fly? This kite soars because you’re holding the kite at the correct angle to the wind. The kite actually has two things (scientifically speaking) going on that help it fly: first, the shape of the wing cause a pressure difference that create lift under the wing surface, the same way that real airplanes generate lift. Second, the angle that the kite hits the wind generates impact lift on the kite, the same way fighter jets generates lift, since fighter jet’s wings are not curved like an airplane’s. In an airplane, the wind flows both over and under the kite, and with this shape, the air flying over the kite is traveling a bit faster than the wind under the kite. Higher wind speed means lower pressure, so the underside of the kite now has a relatively higher pressure, thus pushing the kite upwards into the sky.

Can I add string to any paper airplane and make it into a kite? Anytime someone asks us a question like this, we respond with a very enthusiastic: “I don’t know. Try it!” Then we offer enough tools for the job with a smile. We want kids experimenting with new ideas (even if we’re not entirely sure if they will work). So go ahead, roll up your sleeves, test out your ideas, and prepared to learn.

Here's what you need to do:

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How Airplanes Fly Through Clouds

Monday May 31, 2010
Ever wonder how airplanes fly through those fluffy white things in the sky? If they can't see where they are going, how do they get there?

You might be tempted to think: "GPS!" Ah, yes... but airplanes were flying through clouds long before GPS was ever invented. So how did they do it? That's what this video is all about.

Although most new planes are being outfitted with "glass cockpits", which is to say computer screens with GPS systems, there's really nothing like a plane with vacuum-tube instruments, crackling radios, transponders, VOS, and DMEs. We're going to show you how IFR pilots (those who are specially trained to fly only by instruments without peeking out the window) use their equipment to get the plane down to the ground.

Are you ready? Then strap on your seat belt and get ready to fly with a certified instrument flight instructor...

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Bubble Experiments

Monday May 31, 2010
Magician Tom Noddy

If you’re fascinated by the simple complexity of the standard soap bubble, then this is the lab for you. You can easily transform these ideas into a block-party Bubble Festival, or just have extra fun in the nightly bathtub. Either way, your kids will not only learn about the science of water, molecules, and surface tension, they’ll also leave this lab cleaner than they started (which is highly unusually for science experiments!)


Soap also makes water stretchy. If you’ve ever tried making bubbles with your mouth just using spit, you know that you can’t get the larger, fist-sized spit bubbles to form completely and detach to float away in the air. Spit is 94% water, and water by itself has too much surface tension, too many forces holding the molecules together. When you add soap to it, they relax a bit and stretch out. Soap makes water stretch and form into a bubble.
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Foam Slingshot Rocket

Monday May 31, 2010

You'll see these in toy stores, but why not design your own version? You can add weight to the nose, widen the fins, and lengthen the slingshot part to figure out how to get to to soar further.

 

Materials:

 

  • foam tube (I used a piece of foam from 3/4" pipe insulation, but you can also use a paper towel tube)
  • foam sheet
  • film canister or other small container to hold the rubber band in place (or tape the rubber bands to the outside using duct tape)
  • paper clip
  • 5 to 8 rubber bands
  • scissors
  • hot glue gun
  • duct tape

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Blow Gun Rocket

Monday May 31, 2010
This is the kind of thing I wish I had back in grade school. I could have launched these across the room without anyone being the wiser. Be sure to fold the nose down securely, or you'll have air leaks (and no launch!) This is a smaller version of the Rocketships experiment. Materials: All you need is a
  • sheet of paper
  • a straw
  • tape
  • scissors
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Tetrahedral Kite

Monday May 31, 2010

This is a simpler version of the box kite. By making it out of everyday materials and changing the structure so that it's more rigid, all you need is an afternoon to make this simple and colorful kite.

The directions here are for making a single cell (image is a pyramid of four cells), and the largest we've ever made is ten without needing stronger materials. (It's the straws that bend under the weight). You can add a tail to keep it from spinning during flight.

Here's what you do:

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Robots Game Plan

Monday May 31, 2010

Objective You’re going to be using your circuits together with a frame to build a set of real, working robots. We’re going to spend most of our time learning how to get the electrical components to work together, and not very much time on how they individually work.  For example, we’re not going to talk about how a motor transforms electricity into a spinning motion, but rather how to wire up a set of motors to make a robot move forward and reverse. It’s more important to learn how these elements work.  (The details concerning why they work comes a bit later down the line.)


Robots are electro-mechanical devices, meaning that they rely on both electronics and mechanics to do their ‘thing’.  If a robot has sensors, it can react with its environment and have some degree of intelligence. When scientists design robots, they first determine what they want the robot to do.  Turn on a light?  Make pancakes?  Drive the car? Once you’ve outlined your tasks, then the real fun begins… namely, figuring out exactly how to accomplish the tasks.


About the Experiments The robots in this section aren’t going to look very flashy.  In fact, they may all look about the same – all made of wood, metal, and wires! That’s because we’re focusing on the harder parts (the movement and framework), and leaving the decoration and flashy stuff to you. Once your kids wrap their heads around how to get their robot moving, ask them how they could improve it (make it less wobbly, faster, louder, brighter…etc).


In our live Science Camp Workshops during the summer, we spend an entire day just on this section.  First, we have all the students make the Jigglebot (because it’s the fastest to build) and then the Racecar (so they see how to do the wheel-axle assembly), and then we leave the lab open for the remainder of the time and let them have at the rest of the materials.  The adults basically sit back and let the kids figure out how to build what they want, and are simply available to answer questions, find oddball parts, or drill holes when needed. It’s a great open-lab environment that works well with large groups of students.  (Although if you’re nervous about doing this, just stick with the robots we’ve outlined and your kids will still have an outstanding learning experience.)


Troubleshooting Electricity experiments can be frustrating because unlike other activities, you can’t tell where you’re going wrong if the circuit doesn’t work.  Here are the things we test for when troubleshooting a circuit with the students:


  1. Are the batteries in right? (Flat side goes to the spring.)
  2. Is the connection between the alligator clip and the wire a metal-to-metal connection? (Often kids will clip the alligator clip onto the plastic insulation.)
  3. If it’s an LED that you’re trying to light up, remember that those are picky about which way you hook up the plus and minus (red and black).  Switch the wires if you’re having trouble.
  4. Change out the wires.  Sometimes the wire can break inside – it can get disconnected from the alligator clip inside the plastic insulation, but you can’t see it.  When it doubt, swap out your wires.

The How and Why Explanation Leonardo da Vinci designed a mechanical knight back in the late 1400s.  His drawing sketched out how it could sit upright and move arms, legs, and jaws. Jacques de Vaucanson, in the late 1700s, created the first life-sized mechanical automatons, including a mechanical duck that could flap its wings. It was the Japanese toy industry that really kicked off the mechanical revolution of inventions with complex mechanical inventions that could either paint pictures, fire arrows from a quiver, or serve tea. Not long after, in 1898, Nikola Tesla demonstrated the first radio-controlled torpedo. In 1948, the first electronic autonomous robots (robots that do their ‘thing’ automatically) were Elmer and Elsie, who could sense light, contact, and navigate through a room.


By putting together motors, switches, lights, buzzers, light detectors, tilt and motion sensors, and pressure sensors, you can develop a homemade robot worthy of the science fair’s winner’s circle.


In addition to interacting with their environment, robots need to be able to move somehow.  Robots can move by spinning wheels, turning propellers, moving pistons, grinding gears, or by eccentric (off-center) drive.


While the instructions for the robots focus mainly on the chassis (body or frame) and locomotion (movement), you will want to add lights, buzzers, and any sensors from the Burglar Alarms section to make the robot your very own.


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. How can you add headlights (LEDs) and a horn (buzzer) to the Racecar robot?
  2. Did you figure out how to make the Waterbot go both forward and reverse?
  3. What makes the Jigglebot and Bristlebot move?
  4. What’s the difference between a SPST and DPDT switch? Which would you use when?
  5. How would you improve the Cookie Snatcher Robot Arm?

Build MORE Robots with Unit 10!

Origami Airplane & Ninja Star

Monday May 31, 2010
This is a double-project, because each requires the scraps of the other. The origami airplane requires a square sheet of paper, and the ninja star needs the strip left over from turning a regular sheet of copy paper into a square sheet.

Both of these contraptions fly well if you take your time and make them carefully. Just watch yourself with the ninja star - it's not only fast and furious, the ends are sharp and guaranteed to turn heads... and necks.
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Magic Star

Monday May 31, 2010
My students love making this one, because it's not only a throwing star like the Ninja Star, but also opens up to be a frisbee! You'll need eight sheets of square paper, all the same size. They don't have to be large - I use two that are cut into quarters. Here's what you do:

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Game Plan for Chemical Reactions

Monday May 31, 2010

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Objective You’re going to do several chemistry experiments that expose your kids to the different type of chemical reactions. I want you to focus on honing your observational skills when you do the experiments. Did the temperature, color or volume change? Even the smallest differences can indicate something big is going on. The first thing to do is watch the video on the Chemical Demonstrations website page, and then dive into the experiments.


Main Ideas Chemistry is chocked full of demonstrations and experiments for two big reasons. First, they’re fun. But more importantly, the reason we do experiments in chemistry is to hone your observational skills. Chemistry experiments really speak for themselves, much better than I can ever put into words or show you on a video. And I’m going to hit you with a lot of these chemistry demonstrations to help you develop your observing techniques.


While the kids are playing with the experiments see if you can get them to notice these important ideas. When they can explain these concepts back to you (in their own words or with demonstrations), you’ll know that they’ve mastered the lesson.


About the Experiments A lot of folks get nervous around chemistry. You can’t always ’see’ what’s going on (are there toxic gases generated from that reaction?), and many people have a certain level of fear around chemicals in general.


I don’t want you dipping your hands in molten lead or lying on a bed of nails while someone with a sledgehammer breaks a cinder block on your stomach. Demonstrations of this kind that result in injury are the ones forever burned in the memory of the audience, who are now fearful and have made the generalization that chemicals are dangerous and their effects are bad. In fact, every chemical is potentially harmful if not handled properly. That is why I’ve prepared a special set of chemistry experiments that include step-by-step demonstrations on how to properly handle the chemicals, use them in the experiment, and dispose of them when you’re finished.


Chemistry is predictable, just as dropping a ball from a height always hits the floor. Every time you add 1 teaspoon of baking soda to 1 cup of vinegar, you get the same reaction. It doesn’t simply stop working one time and explode the next. I’m going to walk you through every step of the way, and leave you to observe the reactions and write down what you notice. At first, it’s going to seem like a lot of disjointed ideas floating around, but after awhile, you’ll start to see patterns in the way chemicals interact with each other. Keep working at Chemistry and eventually it will click into place. And if there’s an experiment you don’t want to do, just skip it (or just watch the video). Some of this may be a review for you, especially if you’ve completed Units 3 (Matter) and 8 (Chemistry 1).


The How and Why Explanation There are several different types of chemical reactions: combustion, decomposition, synthesis, and displacement. All chemical reactions somehow fit into one of these, and here’s how you can tell them apart…


Combustion: A combustion reaction gives off energy, usually in the form of heat and light.  The reaction itself includes oxygen combining with another compound to form water, carbon dioxide, and other products. A campfire is an example of wood and oxygen combining to create ash, smoke, and other gases.


Synthesis: This reaction happens when simple compounds come together to form a more complicated compound. The iron (Fe) in a nail combines with oxygen (O2) to form rust, also called iron oxide (Fe2O3).


Oxidation-Reduction (Redox Reaction): When the oxidation numbers of atoms change during the reaction, it’s called a redox reaction. Oxidation happens when a compound loses electrons (increases oxidation state) and reduction occurs when a compound gains electrons (decrease in oxidation state). Electroplating is an example of a redox reaction.


Decomposition: On the other side, a decomposition reaction breaks a complicated molecule into simpler ones. When you leave a bottle of hydrogen peroxide on the counter, it decomposes into water (H2O) and oxygen (O2).


Displacement: There are several different types of displacement reactions, including single, double, and acid-base more on this later). Antacids like calcium hydroxide (CaOH) combine with stomach acid (HCl) to form calcium chloride salt (CaCl2) and water (H2O).


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. What’s true about phenolphthalein? (a) it goes from clear to pink when mixed with bases (b) it’s impossible to spell (c) it is colorless in acidic solutions (d) soluble in water
  2. How does increasing the hydrogen peroxide affect the rate of the iodine clock reaction?
  3. Which chemical turns coldest when added to water? (a) calcium chloride (b) aluminum sulfate (c) ammonium nitrate (d) citric acid
  4. A polymer is: (a) a long piece of spaghetti (b) an element on the periodic table (c) a long molecular chain (d) a plastic bag
  5. What does a cross-linking agent do?
  6. Which of the following are cross-linking agents? (a) calcium (b) borax (c) white glue (d) starch (e) bubble gum
  7. Which substance is both a solid and a liquid? (a) bubble gum (b) slime (c) cornstarch and water (d) last night’s dinner

Answers:


  1. What’s true about phenolphthalein? (a) it goes from clear to pink when mixed with bases (b) it’s impossible to spell (c) it is colorless in acidic solutions (d) soluble in water
  2. How does increasing the hydrogen peroxide affect the rate of the iodine clock reaction? By accelerating the first reaction, you can shorten the time it takes the solution to change color. There are a few ways to do this: You can decrease the pH (increasing H+ concentration), or increase the iodide or hydrogen peroxide. (To lengthen the time delay, add more sodium thiosulfate.)
  3. Which chemical turns coldest when added to water? (a) calcium chloride (b) aluminum sulfate (c) ammonium nitrate (d) citric acid
  4. A polymer is: (a) a long piece of spaghetti (b) an element on the periodic table (c) a long molecular chain (d) a plastic bag
  5. What does a cross-linking agent do? Coagulates the polymers. (Turns the long polymer chains into something that looks more like a fishnet.)
  6. Which of the following are cross-linking agents? (a) calcium (b) borax (c) white glue (d) starch (e) bubble gum
  7. Which substance is both a solid and a liquid? (a) bubble gum (b) slime (c) cornstarch and water (d) last night’s dinner

Robots Shop List

Monday May 31, 2010

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


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NOTE: Radio Shack part numbers have been replaced. Click here for full chart.


This is a Bonus Lab, which means that the experiments in this section require materials which are more expensive and hard to find than the average grocery store. Use the experiments in this section for kids wanting to go even further and deeper into the subject. Since these are more involved, be sure to browse through the videos for these experiments first before purchasing materials for these additional labs.


This lab builds on the ideas from the Electric Lab, and actually reuses a number of components from it. You’ll want to cross off the items you already purchased from the Electricity Shopping List so you don’t duplicate.


Materials

  • AA battery pack  – If you are planning to make all the robots, you’ll need 20 battery holders and 40 AA batteries. However, you can get by with only 2 battery packs if you reuse these from one robot project to the next, or by not attaching the pack to the robot and simply connecting the power to your circuit.
  • 3VDC motors  – If you don’t want to rip apart one robot to build another, you’ll need 22 motors to build all 18 robots. Otherwise, you can get by with about four and reuse the motors with each new project.
  • Alligator clip leads – If you don’t want to reuse these with each robot, you’ll need 46 clip leads. Otherwise, you can get by with a set of 10 wires.
  • SPST push-button switch
  • Enough AA batteries for your battery cases (Cheap dollar-store “heavy duty” type are perfect. Do NOT use alkaline batteries like Duracell or Energizer!)
  • 19 wheels (tops from film canisters, small yogurt containers, milk jugs, orange juice, etc. Only two of these can be large ones like old CDs.)
  • 12 straws
  • 4 old brushes (at least 3 are old toothbrushes, and one can be an old scrubbing brush)
  • 3 tacks
  • 2 index cards
  • 8-12 empty plastic water or soda bottles
  • 4-6 markers or pens and a big piece of paper (like posterboard)
  • 2 blocks of foam (2” x 4” x 6” or larger). You can use different shapes of foam blocks. The packing material from boxes work great, and they are cheap!
  • scrap of cardboard
  • 5 large paper clips
  • 9 brass fasteners
  • cork from a wine bottle
  • long bolt (at least 3″ long) with hexnut
  • 3 wooden spring-type clothespins
  • 25 wooden skewers
  • Film canister (or similar candy tube)
  • 9 propellers to make all 7 robots that use propellers. However, you can reuse these simply by pulling them off one robot and sticking them on another. You can rip these off old toys, cheap fans, or get them from your local hobby store – make sure they fit onto your motor shaft!
  • 1 tiny gear that fits onto your motor shaft, and one larger gear that slides onto a skewer (you can rip these out of an old toy, printer, etc.). There’s only one robot that requires a gear set.
  • Plastic soap container (optional for if you want to make a remote-control for your robots)
  • 50 popsicle sticks (at least one is the smaller size, the rest can be tongue-depressor size)

Tools


  • Tape
  • Scissors
  • Hot glue gun
  • Optional: Drill with drill bits

Electricity Shop List

Monday May 31, 2010

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


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We’re going to reuse some of the materials listed here that are more expensive, like the motors, batteries, wires, switches, lights, etc. in the Laser Lab and the Robot Lab, so you can get a couple extras if you don’t want to tear apart your projects after you’ve built them.


Note to e-Science students: These materials are from Unit 10.


Materials

  • Regular sized latex balloon
  • Ping pong ball
  • Bubble solution (make your own with 1 cup clear Ivory dish soap + 12 cups cold water)
  • Yard stick (AKA meter stick)
  • Soup spoon (bigger is better)
  • 3 large paper clips
  • 8 brass fasteners
  • 2 index cards or scraps of cardboard
  • AA battery pack
  • LEDs
  • 3VDC motor
  • 10 alligator clip leads
  • SPST push-button switch
  • 1K potentiometers
  • Metal jewelry
  • AA batteries for your battery case (Cheap dollar-store “heavy duty” type are perfect. Do NOT use alkaline batteries like Duracell or Energizer!)
  • Optional: Buzzer (Jameco 24872)

Tools


  • Tape
  • Scissors

Sled Kite

Monday May 31, 2010

I carried one of these kites in my backpack in grade school, as it collapses down very small when not in use. You can make smaller versions from still paper, but the one we're going to do uses plastic.

Here's what you need to get:

Two 24 inch wood dowels (or two 24 inch long plastic balloon sticks), four donut stickers (also known as page reinforcement stickers), string, plastic garbage bags, tape and scissors.

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I carried one of these kites in my backpack in grade school, as it collapses down very small when not in use. You can make smaller versions from still paper, but the one we're going to do uses plastic.

Here's what you need to get:

Two 24 inch wood dowels (or two 24 inch long plastic balloon sticks), four donut stickers (also known as page reinforcement stickers), string, plastic garbage bags, tape and scissors.

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Grinder Gearworks

Monday May 31, 2010

Have you tried sticking a plastic wheel straight onto a motor shaft to create a race car? The first thing you’ll find is that the shaft is usually so slick that it doesn’t stay attached to the wheel without a ton of glue. And IF you’re able to attach the wheel to the motor firmly, it usually doesn’t have enough ‘oomph’ to turn the wheel without a push-start. The trouble is that you’ve got too much speed and not enough torque at the wheel.


The motor will generate the certain amount of power, but you can use that power in different ways. For example, a fan needs to be turning at high speed to be of any use, so it makes sense to simply strap a propeller onto the shaft and power up the motor. However, if you need a motor shaft to spin more slowly and with more ‘oomph’, then you need to add a couple of gears to help you do this.


When we build these race cars with college students, we made larger versions that could really transport them across the parking lot. Only instead of a tiny hobby motor turning the pinion (the gear attached to the motor shaft) as we’re going to do in our experiment here, the students powered their ride-on cars with a battery-powered drill they had to hold while riding it across the floor.


The biggest challenge students faced was selecting the gears. Depending on the student’s weight and rolling friction of the wheels, they would need to find the right gear combo for their car. The main thing to keep in mind is that you always trade speed for torque (twisting motion).


In the case with gears, the power is always the same (from the drill), but we slowed the rotation speed way down to increase the amount of torque (how much ‘oomph’ a wheel had to turn) in order to get it rolling. We’re going to experiment with this idea by creating our own geared race cars. Are you ready?


Need help finding gears?


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Game Plan for Slime Science

Monday May 31, 2010

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Objective When you think of slime, do you imagine slugs, snails, and puppy kisses? Or does the science fiction film The Blob come to mind? Any way you picture it, slime is definitely slippery, slithery, and just plain icky — and a perfect forum for learning real science.


Imagine a plate of spaghetti. The noodles slide around and don’t clump together, just like the long chains of molecules (called polymers) that make up slime. They slide around without getting tangled up. The pasta by itself (fresh from the boiling water) doesn’t hold together until you put the sauce on.  Slime works the same way. Long, spaghetti-like chains of molecules don’t clump together until you add the sauce … until you add something to cross-link the molecule strands together.


About the Experiment To make our different slimes, we’ll be using borax as the cross-linking agent.  There a lots of different polymers you can try, including starch, glue, and polyvinyl alcohol.  The polymer (usually glue) mixture is the “spaghetti” (the long chain of molecules), and the “sauce” is the borax mixture (the cross-linking agent).  You need both in order to create slime. Keep your slime in the fridge for a week, or a month in the freezer (although it might change colors). Nuke it in the microwave for a few seconds to thaw.


The How and Why Explanation The cross-linking agent in the slime mixtures can be either liquid starch or borax (sodium tetraborate).  When you mix the glue and water together, you’ve got a cup full of long molecule chains, like a pile of ropes.  When you cross-link the polymers, it’s like building a net with the rope, and it happens very quickly to give you that rubbery, stretchy substance kids are so fond of.


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. A polymer is: (a) a long piece of spaghetti  (b) an element on the periodic table (c) a long molecular chain (d) a plastic bag
  2. What does a cross-linking agent do?
  3. Which of the following are cross-linking agents?  (a) calcium  (b) borax  (c) white glue    (d) starch  (e) guar gum
  4. What does PVA stand for?  What kind of water does it mix with?
  5. Which substance is both a solid and a liquid?  (a) guar gum  (b) bouncy putty (c) starch slime (d) corny slime

Swamp Muck Science Game Plan

Monday May 31, 2010

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Objective This experiment will teach you about the different types of filtration as you turn your coffee back into clear water as well as the swamp muck from the back yard.   You can test out other types of “swamp muck” by mixing together other liquids (water, orange juice, etc.) and solids (citrus pulp, dirt, etc.).  Stay away from carrot juice, grape juice, and beets — they won’t work with this type of filter.


About the Experiment Ever wonder how the water draining down your sink gets clean again? Think about it: The water you use to clean your dishes is the same water that runs through the toilet.  There is only one water pipe to the house, and that source provides water for the dishwasher, tub, sink, washing machine, toilet, fish tank, and water filter on the front of your fridge.  And there’s only one drain from your house, too!  How can you be sure what’s in the water you’re using?


In our live Science Camp Workshops during the summer, we let the kids bring in their own samples which usually includes a blenderized version of leftovers from dinner, plant trimmings, coffee grounds, and dirt. It’s quite a smelly class once everyone cracks open their samples!


The How and Why Explanation There are several steps to understand as we go along:


  • Aeration:  Aerate water to release the trapped gas.  You do this in the experiment by pouring the water from one cup to another.
  • Coagulation: Alum collects small dirt particles, forming larger, sticky particles called floc.
  • Sedimentation: The larger floc particles settle to the bottom of the cup.
  • Filtration:  The smaller floc particles are trapped in the layer of sand and cotton.
  • Disinfection:  A small amount of disinfectant is added to kill the remaining bacteria.  This is for informational purposes only — we won’t be doing it in this experiment.

Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. What is the alum used for in the water filtration experiment? (a) to adjust the pH  (b) to form floc (c) to float to the top (d) to purify the sample
  2. What does the activated carbon do? (a) turns the cotton balls black   (b) sinks the floc  (c) adjusts the pH (d) adds to the filtering power of the cotton (e) none of the above (f) all of the above
  3. Draw a sketch of your filter, labeling the different layers.

Diamond Kite

Monday May 31, 2010

Did you notice how BIG these kites can get? And yes, that's me in the photo, at full size!

If you're looking for a kite that will lift you off your feet, THIS IS THE ONE! I'm going to show you how to build a smaller version first, so you get the hang of how it goes together.

Afterward, you can make a 6-foot, 9-foot, or 12-foot model. Just keep your proportions right and find strong, lightweight materials (bamboo is a popular choice, but watch the wall-thickness or it too can get heavy).

The photo here is the 9-foot tall version of this kite, which sports a 25-foot tail. To fly this, you'll need a lot of wind, so if you live near the beach, you might be able to get this up. Otherwise, you can try to get it airborne by doing what I used to do with mine - tie it to the bumper of your pickup truck and drive out in the country with about a mile of strong string!

The 6-foot versions in a strong wind will generate enough to lift small kids, so watch out (and get your camera).

If you can find balloon sticks (white plastic stiff tubes about 3 feet long), use them. They’re inexpensive, lightweight, and easy to work with. Otherwise, use wood dowels from a hardware store or 36” bamboo gardening stakes from a nursery.

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Rocketry Game Plan

Monday May 31, 2010

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Objective Kids love going fast and blowing things skyward. This set of experiments should satisfy both needs.  The goal is to not only provide them with a safe set of activities that will keep their eyebrows intact, but also to get them really excited about aerodynamics and rocket design by building projects that really work. Most rockets will require a certain amount of tweaking (like the Flying Machines experiments did) in order to fly straight. This is an excellent time to hone their observation skills and get them into the habit of changing and testing only one thing at a time.


We’re going to continue learning about pressure as we generate high pressure through both bicycle pumps as well as chemical reactions. The first thing to do is watch the video on the Rocketry website page, and then dive into the experiments.


Main Ideas While the kids are playing with the experiments see if you can get them to notice these important ideas. When they can explain these concepts back to you (in their own words or with demonstrations), you’ll know that they’ve mastered the lesson.


  1. For every action, there is an equal and opposite reaction.
  2. The position of the center of pressure relative to the center of gravity of a rocket determines how stable the flight will be.

About the Experiments The experiments in this section vary from small indoor flights to rockets that go over a football field in distance. All rockets move by a quick release in pressure. Once your rocket takes flight, take a clear look (or better, a video so you can watch it a few times over) at how it flies when it’s up there.  By launching at an angle instead of straight up, you’ll get a better view… just be sure your launch area is clear.


Stability of Flight: A rocket has two key points (CP & CG, covered in the Flying Machines experiments) that you need to know in order to have stable flight.  Here’s how you find and adjust them:


  1. Finding the Center of Pressure: You can find center of pressure by tying a string around the rocket body and swinging it around your head. The balance point is your center of pressure.  Mark the point as CP.
  2. Finding the Center of Gravity: Balance your rocket on a pencil tip. Mark the point as CG. Note if this is forward or aft of your CP.
  3. To adjust the CG/CP: It’s easier to adjust the CG – add weight to the nose or more fins to the tail section.  Re-measure your CG when you’re done.
  4. Read more about rocket stability here.

The How and Why Explanation Rockets shoot skyward with massive amounts of thrust, produced by chemical reaction or air pressure.  Scientists create the thrust force by shoving a lot of gas (either air itself, or the gas left over from the combustion of a propellant) out small exit nozzles.


According to the universal laws of motion, for every action, there is equal and opposite reaction.  If flames shoot out of the rocket downwards, the rocket itself will soar upwards.  It’s the same thing if you blow up a balloon and let it go—the air inside the balloon goes to the left, and the balloon zips off to the right (at least, initially, until the balloon neck turns into a thrust-vectored nozzle, but don’t be concerned about that just now).


A rocket has a few parts different from an airplane.  One of the main differences is the absence of wings.  Rockets utilize fins, which help steer the rocket, while airplanes use wings to generate lift.  Rocket fins are more like the rudder of an airplane than the wings.


Another difference is the how rockets get their speed.  Airplanes generate thrust from a rotating blade, whereas rockets get their movement by squeezing down a high-energy gaseous flow and squeezing it out a tiny exit hole.


If you’ve ever used a garden hose, you already know how to make the water stream out faster by placing your thumb over the end of the hose.  You’re decreasing the amount of area the water has to exit the hose, but there’s still the same amount of water flowing out, so the water compensates by increasing its velocity.  This is the secret to converging rocket nozzles—squeeze the flow down and out a small exit hole to increase velocity.


The rockets we’re about to build get their thrust by generating enough pressure and releasing that pressure very quickly.  You will generate pressure both by pumping and by chemical reaction, which generates gaseous products. Let’s get started!


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. If you inflate a balloon (don’t tie the end), which direction does the air in the balloon and the balloon itself travel?   (a) both the same way (b) in opposite directions  (c) nothing happens
  2. When you drop an effervescent tablet into water, what happens? (a) bubbles foam up (b) it burps (c) carbon dioxide gas is released    (d) it produces a chemical reaction that can propel a rocket skyward
  3. Puff Rockets use which of the following propellants?  (a) air pressure (b) chemical reactions (c) both (d) neither
  4. The most dangerous parts of the Water Rocket experiment is are: (a) working with high pressure (b) that you’ve stripped out the threads that normally secure the cap in place, and now it’s easier to accidentally release the rocket and shoot someone’s eyeballs out (c) reusing the bottles over and over causes fissures and cracks to form in the bottle, increasing the chances of bursting if you don’t replace the bottle after every 7-10 launches (d) all of the above and more
  5. The most important things to remember when launching water rockets are: (a) safety goggles or face shield (b) 70 psi maximum air pressure (c) always hold the valve-side down when holding the bottle (d) only use soda bottles that are build to hold pressure (e) never water bottles, juice bottles, sports drink bottles, or any others that don’t say pssssst! when you first open them
  6. To get the multi-staging rockets to work correctly, where does the trigger need to be?  (a) inside the first balloon (b) on the string (c) in the straw (d) squished between the first balloon and the cup
  7. How does a Slingshot Rocket work?  Where does the thrust come from?
  8. If your Blow Gun Rocket straw rips loose, what can you do to quickly repair it without rebuilding the entire rocket?

Flying Machines Game Plan

Monday May 31, 2010

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Objective You’re going to do several experiments that change air pressure and mystify your kids. The goal is to set them thinking about how and why things fly (you’ll do this by learning about air pressure and Bernoulli’s law, but you don’t need to tell them that). The first thing to do is watch the video below and then dive into the experiments.

Main Ideas While the kids are playing with the experiments see if you can get them to notice these important ideas. When they can explain these concepts back to you (in their own words or with demonstrations), you’ll know that they’ve mastered the lesson.

  1. Air pressure is all around us. Air pushes downward and creates pressure on all things.
  2. Air pressure changes all the time.
  3. Higher pressure always pushes.
  4. The faster air travels over a surface, the less time it has to push down on that surface and create pressure. Fast moving air creates low pressure regions. (Bernoulli’s Law).
  5. The four fundamental forces on an airplane are lift, weight, thrust, and drag.

About the Experiments There are a lot of experiments in this section that will hone your child’s observation skills. About half the experiments are on flying machines and the other half consist of air pressure demonstrations. When their airplane doesn’t work right, ask them what exactly it’s doing (or not doing), and then take a more careful look at how it’s constructed. Focus on watching what happens when you make small changes, and try to change only one thing at a time.

The How and Why Explanation There’s air surrounding us everywhere, all at the same pressure of 14.7 pounds per square inch (psi). You feel the same force on your skin whether you’re on the ceiling or the floor, under the bed or in the shower.

An interesting thing happens when you change a pocket of air pressure – things start to move. This difference in pressure causes movement that creates winds, tornadoes, airplanes to fly, and some of the experiments we’re about to do together.

An important thing to remember is that higher pressure always pushes stuff around. While lower pressure does not “pull,” we think of higher pressure as a “push”. The higher pressure inside a balloon pushes outward and keeps the balloon in a round shape.

Weird stuff happens with fast-moving air particles. When air moves quickly, it doesn’t have time to push on a nearby surface, such as an airplane wing. The air just zooms by, barely having time to touch the surface, so not much air weight gets put on the surface. Less weight means less force on the area. You can think of “pressure” as force on a given area or surface. Therefore, a less or lower pressure region occurs wherever there is fast air movement.

There’s a reason airplane wings are rounded on top and flat on the bottom. The rounded top wing surface makes the air rush by faster than if it were flat. When you put your thumb over the end of a gardening hose, the water comes out faster when you decrease the size of the opening. The same thing happens to the air above the wing: the wind rushing by the wing has less space now that the wing is curved, so it zips over the wing faster, and creates a lower pressure area than the air at the bottom of the wing.

The Wright brothers figured how to keep an airplane stable in flight by trying out a new idea, watching it carefully, and changing only one thing at a time to improve it. One of their biggest problems was finding a method for generating enough speed to get off the ground. They also took an airfoil (a fancy word for “airplane wing”), turned it sideways, and rotated it around quickly to produce the first real propeller that could generate an efficient amount of thrust to fly an aircraft.  Before the Wright brothers perfected the airfoil, people had been using the same “screw” design created by Archimedes in 250 BC.  This twist in the propeller was such a superior design that modern propellers are only 5% more efficient than those created a hundred years ago by the two brilliant Wright brothers.

Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:

  1. Higher pressure does which? (a) pushes (b) pulls (c) decreases temperature (d) meows (e) causes winds, storms, and airplanes to fly
  2. The tips on the edge of a paper airplane wing provide more lift by: (a) flapping a lot
    (b) destroying wingtip vortices that kill lift (c) getting stuck in a tree more easily (d) decreasing speed
  3. In the ping pong ball and funnel experiment, the ball stayed in the funnel was because:         (a) you couldn’t blow hard enough (b) you glued it into the funnel (c) the ball had a hole in it  (d) the fast blowing caused a low-pressure region around the ball, causing the surrounding atmospheric pressure to be a higher pressure, thus pushing the ball into the funnel
  4. In the sneaky bottle experiment, which of the two bottles was the balloon able to inflate in? (a) the one with a hole (b) the one with no holes (c) the one the kid fit inside
  5. If your plane takes a nose dive, you should try (a) changing the elevators by pinching the edges (b) change the dihedral angle (c) change how you throw it (d) all of the above
  6. What are the four forces that act on every airplane in flight?
  7. Draw a quick sketch of your plane viewed from the front with a positive dihedral.
  8. Why does the index card stay in place when you invert the cup of water in the magic water glass trick?
  9. When the balloon was squished into the jam jar with the snuffed candle, where was the higher pressure?

10.  Why does the water stop streaming out of the bottle when you put the cap on in the streaming water experiment?  Why does the water come out if you squeeze the capped bottle?

11.  How can you make the fountain bottle shoot even higher?

12.  If you were designing your own “Flying Paper Machine Kit”, what would be inside the box?

13.  What’s the one thing you need to remember about higher pressure?

14.  What keep an airplane from falling?

15.  Where is the low pressure area on an airplane wing?


Rocketry Shop List

Monday May 31, 2010

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


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Materials

  • 10 sheets of 8×11” paper
  • 5 index cards
  • 7-9” latex balloon
  • 15 large straws
  • 5 small straws (make sure these slide easily into the larger straws)
  • wooden spring-type clothespin
  • 4 popsicle sticks (any size)
  • 5 skewers
  • 8 milk jug lids, film tops, or other small, plastic lids that are round for wheels
  • 6” long piece of 3/4” foam pipe insulation
  • foam sheet from a craft store
  • 4 Fuji film canisters or plastic M&M containers (check recycle bin at a photo developing store)
  • 2 small paper clips
  • 8 rubber bands
  • effervescent tablets (generic alka seltzer works great)
  • clean, empty shampoo or lotion bottle
  • small piece of squishy foam or packing peanut
  • wood skewer (should fit inside straws)
  • bike pump
  • needle valve
  • neoprene stopper that fits a 2L soda bottle
  • empty 2-liter soda bottles

Tools


  • duct tape
  • scissors
  • tape
  • hot glue gun

Optional Materials: These rockets go a lot further, but also require adult help to create or are more expensive to build. Watch the video first before starting these projects!


  • razor blade
  • vice or vice grips
  • drill with ½” drill bit (spade bit is best)
  • air compressor and/or air tank
  • spray-nozzle for compressor/tank
  • 3 foot piece of metal tubing that fits just inside the larger straws (listed above)
  • car tire valve (find this at a tire repair shop)
  • 2 to 5 empty 2-liter soda bottles with caps
  • 5 ball bearings , ½” diameter
  • 4 neodymium (super-strong) magnets (1/2″ cube)
  • paper towel tube
  • 1 inch wide bike tube (at least 3 feet long)
  • 12” long x 1/2” diameter PVC pipe

Kites Shop List

Monday May 31, 2010

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


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Materials

  • 11”x17” sheet of paper (or tape two 8 ½” x 11” to make this size)
  • A big roll of string (enough for six kites)
  • 20 donut stickers (also known as page reinforcement stickers)
  • 50 straws
  • 4 sheets of tissue paper
  • 10-20’ crepe paper streamer for kite tail
  • 3 wire coat hangers or 36” balloon sticks (these are a better choice if you can find them)
  • Five plastic garbage bags
  • 2 foam plates (at least 4 inches in diameter)
  • 6”x4” clean foam meat tray

Tools

  • Stapler
  • Tape
  • Scissors
  • Hot glue gun with glue sticks
  • Glue sticks (the retractable kind)
  • Duct tape

Dragon Kite

Monday May 31, 2010

This kite is sometimes referred to as a "Comet Kite", as it has a main head area and a loooong tail section. We recommend making the kite from lightweight garbage bags, as they tend to hold up better than tissue paper, and don't require sewing they way ripstop nylon material does.

Here's what you need to get: Wire coat hanger or thin plastic dowel, string, straw, plastic garbage bags, tape, and scissors.

Here's what you do:
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Flying Machines Shop List

Monday May 31, 2010

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


Click here for a printer-friendly version of this page.


Materials

Materials


  • Water
  • Bathtub or sink
  • Bowl
  • Scrap of paper towel
  • 2 clear cups
  • 25 straws
  • Small lump of clay
  • 3 balloons
  • 2 thumbtacks
  • Plastic funnel
  • Ping pong ball
  • Plastic garbage bag
  • Red and blue food coloring
  • 20 sheets of 8 ½” x 11” paper
  • Pencil
  • Rubber band
  • Popsicle stick
  • 2 small paper clips
  • 2 identical water glasses
  • 10 index cards (large enough to cover the mouth of the water glass)
  • 3 empty soda cans
  • Empty glass jar
  • Empty 2-liter soda bottle
  • 2 empty water bottles
  • 12” flexible tubing (or use a flexible straw)
  • Matches with adult help
  • Test tube
  • 2-liter soda bottle



Tools


  • Scissors
  • Tongs
  • Tape
  • Duct tape
  • Hair dryer
  • Stove with adult help

Optional


The projects that require these items are either more expensive or harder to build and require adult help. Watch the videos before shopping for these items!


Why do airplanes need wings?

Monday May 31, 2010

 

Every flying thing, whether it's an airplane, spacecraft, soccer ball, or flying kid, experiences four aerodynamic forces: lift, weight, thrust, and drag. An airplane uses a propeller or jet engine to generate thrust. The wings create lift. The smooth, pencil-thin shape minimizes drag. And the molecules that make up the airplane attribute to the weight.

Think of a time when you were riding in a fast-moving car. Imagine rolling down the window and sticking out your hand, palm down. The wind slips over your hand. Suppose you turn your palm to face the horizon. In which position do you think you would feel more force against your hand?

When designing airplanes, engineers pay attention to details, such as the position of two important points: the center of gravity and the center of pressure (also called the center of lift). On an airplane, if the center of gravity and center of pressure points are reversed, the aircraft’s flight is unstable and it will somersault into chaos. The same is true for rockets and missiles!

How to Build an Airplane

Materials: balsa wood flyer

This video shows how to use a balsa airplane to show what all the parts (rudder, wings, elevator, fuselage) are for.  You can pick one up for a few dollars, usually at a toy store, or make your own (see second video below).

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Ping Pong Funnel

Monday May 31, 2010

As you blow into the funnel, the air under the ball moves faster than the other air surrounding the ball, which generates an area of lower air pressure. The pressure under the ball is therefore lower than the surrounding air which is, by comparison, at a higher pressure. This higher pressure pushes the ball back into the funnel, no matter how hard you blow or which way you hold the funnel. The harder you blow, the more stuck the ball becomes. Cool.


Materials: A funnel and a ping pong ball


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Kites Game Plan

Monday May 31, 2010

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Objective You’re going to build on the Flying Machines concepts by building larger airfoils called Kites.  The goal is to get them even more excited about fluid mechanics and aerodynamics by building projects that really fly. We’re going to continue learning about air pressure and Bernoulli’s law through the different kite designs. The first thing to do is watch the video on the Kites website page, and then dive into the experiments.


Main Ideas While the kids are playing with the experiments see if you can get them to notice these important ideas. When they can explain these concepts back to you (in their own words or with demonstrations), you’ll know that they’ve mastered the lesson.


  1. Higher pressure always pushes.
  2. The faster air travels over a surface, the less time it has to push down on that surface and create pressure. Fast moving air creates low pressure regions. (Bernoulli’s Law).
  3. The four fundamental forces on a kite are lift, weight, thrust, and drag. (The thrust is the pull on the string, and the lift occurs when wind flows over the top and bottom of the kite.)

About the Experiments The experiments in this section will take more time to put together, as you are building several different kite designs, including the box kite, the dragon, the diamond, and the rotor kite. If your kite doesn’t take off immediately, ask your child how it doesn’t work… did the nose tip over, did it spin, flip, or just tumble?  Asking better questions is one of the key ingredients to making a great a scientist. Focus on watching what happens when you make small changes, and try to change only one thing at a time.


Before flight, hold your kite where the main line attaches to the bridle (the part that attaches to the string spool).  Adjust the strings so that the kite hangs about 30 degrees into the wind.  Use your fingers on the bridle on a windy day to find the “magic spot” or the place where your kite picks right up and flies best.


Moving the bridle forward makes the kite fly higher in smooth winds and   moving it backward helps it fly in gusty winds.  If your kite fails to rise, try a windier spot or a shorter tail.  If it flies then quickly crashes, you may need to shorten your bridle or change the angle.  If your kite spins around and around while flying, add more tail length.


The How and Why Explanation Kites are airplanes on a string.  They use both high and low pressure to gain altitude and soar skyward.  Not all kites need tails—the tail section helps stabilize an otherwise unstable kite design by adding a bit of weight near the bottom.  While kites need to be lightweight, the framework needs to be strong, as they can withstand winds greater than 70 mph at higher altitudes.


To launch a kite, you can start with it on the ground and simply start running, hold it in your hands and toss it behind you as you run, or have someone hold it for you and toss it up as you start to run with the string. The best launch method depends on the kind of kite you’re working with. For example, the Bat Kite just needs to be tossed into the air with a kid running in front of it, while the rotor kite is going to require a windy day or a bicycle.


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


1. Kites need string so: (a) they don’t get lost (b) to hold them at the correct angle to the wind (c) so you can pull the kite in when you’re done  (d) all the above


2. Kites can be in the shape of which ones?  (a) box (b) pyramid  (c) diamond (d) hippos


3. Which part of the kite is the most adjustable?  (a) the kite skin (b) the tail (c) the bridle (d) the frame


4. Which kite is collapsible and easy to carry? (a) sled (b) dragon (c) bat   (d) rotor (e) tetrahedral (f) diamond


5. If your kite crashes to the ground, what two things can you try changing?


6. How do you get your kite to spin in circles?


7. How much wind does the Rotor kite need? (a) a day at the beach could work (b) zero (c) winds like a hurricane (d) running ought to do it


8. What do you do if your kite doesn’t lift off the ground?  (a) run faster    (b) find a windier spot (c) let go of the kite (d) stop stepping on it (e) all of the above


9. Where is the higher pressure area on the kite during flight? (a) the topside (b) the underside (c) the tail (d) nowhere


10. What is the frame for on a kite?  (a) to keep the kite in the right shape (b) to provide weight in the right places (c) so it can break (d) so you have something to attach the bridle to


11. Which kite works with the least amount of wind?


Lasers Game Plan

Monday May 31, 2010

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Objective You will learn about light waves and optics in this Laser Lab. Kids will play with their lasers and see what happens when they shine it on and through different objects.


Laser Safety Before we start our laser experiments, you’ll need eye protection – tinted UV ski goggles are great to use, as are large-framed sunglasses, but understand that these methods of eye protection will not protect your eyes from a direct beam.  They are intended as a general safety precaution against laser beam scatter.  (If you’re using a Class I or II laser, you don’t need to wear the goggles – but it is a good habit to get the kids into, so it’s up to you.)


About the Experiment This lab is an excellent opportunity for kids to practice asking better questions. Don’t worry too much about academics at this point – just give them a box of materials and let them figure these things out on their own. One of the neat things you can do is ask the kids some questions about what they are doing.


For example, when they shine their laser on a window, you’ll see part of the beam pass through while another part gets reflected back… now why is that? And why does the CD produce so many different reflections?  Sometimes these reflections are hard to find actually seeing the beam itself.  While red lasers are impossible to see with the naked eye, you can make your beam visible by doing your experiments in a steamy dark bathroom (after a hot shower).


The How and Why The word “LASER” stands for Light Amplification by Stimulated Emission of Radiation.   A laser is an optical light source that emits a concentrated beam of photons.  Lasers are usually monochromatic – the light that shoots out is usually one wavelength and color, and is in a narrow beam.


By contrast, light from a regular incandescent light bulb covers the entire spectrum as well as scatters all over the room. (Which is good, because could you light up a room with a narrow beam of light?)


There are about a hundred different types of atoms in the entire universe, and they are always vibrating, moving, and rotating. When you add energy to an atom, it vibrates faster and moves around a lot more. When the atoms relax back down to their “normal” state, they emit a photon (a light particle).  A laser controls the way energized atoms release photons.


Imagine kids zooming all over the playground, a mixture of joy and chaos.  Light from an incandescent light bulb works the same way – the bulb emits high energy photons that bounce all over the place.  Can you round up the kids and get them to jumping in unison?  Sure you can – just hit the play button on a song, and they’ll be clapping and stamping together.  You can do the same with light – when you focus the energy into a narrow beam, it’s much more powerful than having it scattered all over the place. That’s just what a laser is – a high-energy, highly-focused beam of light.


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. What does LASER stand for?
  2. How is a laser different from an incandescent bulb?
  3. What are two things that can split a laser beam?
  4. How do you make a laser beam visible?
  5. What’s the secret behind the laser light show?
  6. How do lasers damage things?

Rocketships

Monday May 31, 2010

If you don't have access to an air compressor or air tank with a spray-nozzle, you can either make your own rocket launcher (watch second video below), or make the blow-gun rockets. Either way, you're going to be launching sky-high in no time!

 

Materials:

 

  • Two straws each in two different sizes
  • two sheets
  • index cards
  • scissors
  • tape
  • hot glue gun
  • air compressor or air tank with spray-nozzle
  • metal tubing that fits just inside the larger straws

 

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Lasers Shop List

Monday May 31, 2010

How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


You do not need to do ALL the experiments – just pick the ones you want to do! Look over the experiments and note which items are needed, and off you go!


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NOTE: Radio Shack part numbers have been replaced. Click here for full chart.


Materials

Materials for the Laser Light Show


Materials for the Flashlight-Laser Tag, Laser Burglar Alarm, Door Alarm


Materials for Crystal Radio Project: (This is a battery-free radio!)


Magic Water Glass Trick

Monday May 31, 2010

Where’s the pressure difference in this trick?


At the opening of the glass. The water inside the glass weighs a pound at best, and, depending on the size of the opening of the glass, the air pressure is exerting 15-30 pounds upward on the bottom of the card. Guess who wins? Tip, when you get good at this experiment, try doing it over a friend’s head!


Materials: a glass, and an index card large enough to completely cover the mouth of the glass.


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Hot Air Balloon

Monday May 31, 2010

About 400 years ago, Leonardo da Vinci wanted to fly… so he studied the only flying things around at that time: birds and insects. Then he did what any normal kid would do—he drew pictures of flying machines!


Centuries later, a toy company found his drawing for an ornithopter, a machine that flew by flapping its wings (unlike an airplane, which has non-moving wings). The problem (and secret to the toy’s popularity) was that with its wing-flapping design, the ornithopter could not be steered and was unpredictable: It zoomed, dipped, rolled, and looped through the sky. Sick bags, anyone?


Hot air balloons that took people into the air first lifted off the ground in the 1780s, shortly after Leonardo da Vinci’s plans for the ornithopter took flight. While limited seating and steering were still major problems to overcome, let’s get a feeling for what our scientific forefathers experienced as we make a balloon that can soar high into the morning sky.


Materials: A lightweight plastic garbage bag, duct or masking tape, a hand-held hair dryer. And a COLD morning.


Here’s what you do:


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Diaper Wind Bag

Monday May 31, 2010

Lots of science toy companies will sell you this experiment, but why not make your own? You’ll need to find a loooooong bag, which is why we recommend a diaper genie. A diaper genie is a 25′ long plastic bag, only both ends are open so it’s more like a tube. You can get three 8-foot bags out of one pack.


Kids have a tendency to shove the bag right up to their face and blow, cutting off the air flow from the surrounding air into the bag. When they figure out this experiment and perform it correctly, this is one of those oooh-ahhh experiments that will leave your kids with eyes as big as dinner plates.


Here’s what you do:


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Electricity Game Plan

Monday May 31, 2010

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Objective You’re going to take a deeper look at the atom by stripping off part of it called the electron and messing around with it to make things move, stick, jump, and have bad hairdos. This is an excellent time to hone their observation skills and get them into the habit of changing and testing only one thing at a time.


Main Ideas While the kids are playing with the experiments see if you can get them to notice these important ideas. When they can explain these concepts back to you (in their own words or with demonstrations), you’ll know that they’ve mastered the lesson.


  1. Opposite charges attract, like charges repel.
  2. Electrons cannot be seen, but they are very small particles that are easy to move around.

About the Experiments The experiments in this section are mostly the same ones found in Unit 10, for two reasons.  First, these are the activities we do when we teach Science Camp Workshops during the summer, and we’ve added live video from these workshops so you can see us in action. Second, have you seen how massive Unit 10 is?  We took the feedback we received to heart and now we’ve made Unit 10 a lot more doable by chunking the experiments down into three main categories and minimized the academics so you can focus on getting your kids excited just by doing the coolest experiments from the section.


Electricity experiments can be frustrating because unlike other activities, you can’t tell where you’re going wrong if the circuit doesn’t work.  Here are the things we test for when troubleshooting a circuit with the students:


  1. Are the batteries in right? (Flat side goes to the spring.)
  2. Is the connection between the alligator clip and the wire a metal-to-metal connection? (Often kids will clip the alligator clip onto the plastic insulation.)
  3. If it’s an LED that you’re trying to light up, remember that those are picky about which way you hook up the plus and minus (red and black).  Switch the wires if you’re having trouble.
  4. Change out the wires.  Sometimes the wire can break inside – it can get disconnected from the alligator clip inside the plastic insulation, but you can’t see it.  When it doubt, swap out your wires.

The How and Why Explanation Blow up a balloon. If you rub a balloon on your head, the balloon is now filled up with extra electrons, and now has a negative charge.  Your head now has a positive charge because your head was electrically balanced (same number of positive and negative charges) until the balloon stole your negative electrons, leaving you with an unbalanced positive charge. When you put the balloon close to your head, notice how your hair reaches out for the balloon.  Your hair is positive, the balloon is negative, and you can see how they are attracted to each other!


Your hair stands up when you rub it with a balloon because your head is now positively charged, and all those plus charges don’t like each other (repel). They are trying to get as far away from each other as possible, so they spread far apart.


The triboelectric series is a list that ranks different materials according to how they lose or gain electrons.  Near the top of the list are materials that take on a positive charge, such as air, human skin, glass, rabbit fur, human hair, wool, silk, and aluminum.  Near the bottom of the list are materials that take on a negative charge, such as amber, rubber balloons, copper, brass, gold, cellophane tape, Teflon, and silicone rubber.


When you rub a glass rod with silk, the glass takes on a positive charge and the silk holds the negative charge.  When you rub your head with a balloon, the hair takes on a positive charge and the balloon takes on a negative charge.


When you scuff along the carpet in socks, you gather up an electric charge in your body.  That charge was static until you zapped someone else.  The movement of electric charge is called electric current. When electric current passes through a material, it does it by electrical conduction. There are different kinds of conduction, such as metallic conduction, where electrons flow through a conductor (like metal) and electrolysis, where charged atoms (called ions) flow through liquids.


An electrical circuit is like a NASCAR raceway.  The electrons (race cars) zip around the race loop (wire circuit) super-fast to make stuff happen. Although you can’t see the electrons zipping around the circuit, you can see the effects: lighting up LEDs, sounding buzzers, clicking relays, etc.


There are many different electrical components that make the electrons react in different ways, such as resistors (limit current), capacitors (collect a charge), transistors (gate for electrons), relays (electricity itself activates a switch), diodes (one-way street for electrons), solenoids (electrical magnet), switches (stoplight for electrons), and more.  We’re going to use a combination diode-light-bulb (LED), buzzers, and motors in our circuits right now.


A CIRCUIT looks like a CIRCLE.  When you connect the batteries to the LED with wire and make a circle, the LED lights up.  If you break open the circle, electricity (current) doesn’t flow and the LED turns dark.  LED stands for “Light Emitting Diode”.  Diodes are one-way streets for electricity – they allow electrons to flow one way but not the other.


Let’s get started building circuits!


Questions to Ask When you’ve worked through most of the experiments ask your kids these questions and see how they do:


  1. Why does the hair stick to the balloon? Does the shape of the balloon matter? Does hair color matter? Hair texture? How much goop you have in your hair?
  2. What other things does the balloon stick to?
  3. What happens when you bring the balloon close to a pile of confetti?
  4. Why do you think the ping pong ball moved? Are there other objects you can try instead of the ping pong ball?
  5. Why does the water wiggle and move when you bring the balloon close to it? What if you bring the balloon close to a pan full of water?
  6. Are you able to make the yardstick rotate all the way around in a full circle?
  7. Can we see electrons? What charge does the electron have?
  8. Why does the balloon stick to the wall?
  9. How do you get rid of extra electrons?

Gigantic Solar Balloon

Monday May 31, 2010

solar-balloonWe didn't include this particular experiment in our shopping list, as the tube's kind of expensive and can only be used for one particular experiment, BUT it's an incredible blast to do in the summer.

Here's the main idea - an incredibly loooooong and super-lightweight black plastic garbage bag is filled with air and allowed to heat itself in the sun. In a few short minutes, the entire 60-foot tube tube rises into the air. Before you try this experiment, try the Hot Air Balloon first!

Order the Solar Tube here.

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Bomber Plane

Monday May 31, 2010

This is another favorite of mine - you can fold this one in under two minutes. Make sure you tweak your airplane to get it to fly just the way you want.



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Ring Thing

Monday May 31, 2010

Why can this thing fly? It doesn’t even LOOK like a plane! When I teach at the university, this is the plane that mathematically isn’t supposed to be able to fly! There are endless variations to this project—you can change the number of loops and the size of loops, you can tape two of these together, or you can make a whole pyramid of them. Just be sure to have fun!

Materials: Index card, straw, scissors, tape.

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Butterflying Cups

Monday May 31, 2010

This experiment is one of my favorites to use when teaching university-level fluid mechanics, because it is quite a complex task to demonstrate and analyze the aerodynamic lift. The easiest explanation is that lift is generated by the rotation of the cups. How and why the vortex generates lift is much more complex, but remember that as the air velocity increases, the pressure decreases. And remember... higher pressure regions always push.

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Hangliders

Monday May 31, 2010

Build your own paper version of a soaring, looping flying machine, much like the one DaVinci dreamed of. You can either hold this by the keep (the folded part on the bottom) and throw like a jet, or hold onto the very edge at the back and simply let go from a tall height. Either way, it'll still fly.

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Streak

Monday May 31, 2010

This is one of the fastest plane designs we've come across. Slick, swift, and strong, you'll need a hefty throw to break our record of 127 feet. If you do, let us know so we can celebrate with you!

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Dart Flyer

Monday May 31, 2010
This super-fast dart flyer requires only a sheet of paper and three patient minutes. Take the challenge and dig out a stopwatch and tape measure to record your best "time aloft" and "distance traveled". I usually write mine right onto the wing itself (on the underside).

In fact, each time it flies well, I'll take a measurement and so pretty soon my plane has a data table under the wing. This way, I know which plane to choose in a race!

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Nakamura Lock

Monday May 31, 2010

A classic that we just had to toss into the mix. The best thing about this plane it that it shows you how to fold an airplane without using tape. Notice how the wings of this airplane are different than the stunt plane designs - the swept back design mimics those used on fighter planes from the Air Force.

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Tweaking Your Airplanes

Monday May 31, 2010

iStock_000003125985XSmallWe’ve included several flying designs for you to test, including: stunt planes, fast jets, hang gliders, and a one that, mathematically-speaking, isn’t even supposed to fly.

The trick to any paper airplane, be it a dart, stunt, or glider, is in the tweaking. In order to turn a disappointing nose-diver into a stellar barrel-roller, you’ll need to pay close attention to your dihedral angle (angle the wings make with the horizon) and elevator angle (pinching up or down to the tail section).

Here’s how we do it:

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Roto-Helicopters

Monday May 31, 2010

Did you know that the Wright brothers figured out one of the biggest leaps in propeller technology?  Prop blades had basically stayed the same for about 2,500 years until they figured out to take an airplane wing, turn it sideways and rotate it to create thrust.  The main idea being a wing is that it needs to have a half-twist and the thickness needs to vary along its length (this is because you want to get the same amount of thrust at each point along its length, or one part of the propeller will generate more thrust and rip itself apart).

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Flying Fish

Monday May 31, 2010
We're going to make spinning, flying fish! All you need is a strip of paper and a pair of scissors to make these. If you 're like me, you'll make a whole grocery-bag full of a rainbow assortment and drop them from the upstairs railing - it's quite a show!

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