How does the eye work? If you are amazed as I am about how the different parts of the eye are put together, then this is the lab for you! It's important not only to learn how to take apart video cameras and blenders to find out how they work, but also to be fascinated by how the different parts of living creatures work ... like the eye!
In today’s dissection, we’ll be looking at a cow eye. Because cow eyes are so similar to humans eyes, you’ll learn a lot about your own eyes by dissecting the cow eye. Eyes are a very special organ that form images from the world around you and then send the images to your brain for processing. You will be able to see the cornea, iris, pupil, connecting muscles and veins, and other features.
Materials:
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Click here to go to part:28 Finale!
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a kidney right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
In today’s dissection, we’ll be looking at a kidney. Kidneys are critical for removing toxic waste and regulating the levels of water, sugars, salts, and acids in the bodies of mammals. There are many things that make a kidney interesting, including its unique bean shape and the fact that it contains about a million microscopic structures called nephrons that are key in the blood filtration process.
Materials:
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Click here to go to part 27:Cow Eye Dissection
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a sheep brain right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
In today’s dissection, we’ll be looking at a sheep brain. Brains, while still not entirely understood by biologists or psychologists, are critical for movement, respiration, thought, memory, processing sensory signals, and more. What we talk about in today’s dissection just scratches the surface of all there is to know about the brain, which is the most complex organ in the human body.
Materials:
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Click here to go to part:26 Sheep Kidney Dissection
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a heart right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
In today’s dissection, we’ll be looking at a sheep heart. Like humans, sheep have four-chambered hearts. Hearts are an essential organ--they pump blood through your body to keep you alive!
Materials:
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Click here to go to part:25 Sheep Brain Dissection
In today’s dissection, we’ll be looking at an owl pellet. Owls are carnivores, and they eat things like moles, shrews, rodents, birds, insects, and even crayfish. Owls are unable to digest the bones and fur of these creatures, so they regurgitate (or spit up) what are called pellets--small bundles of all the indigestible parts of the owl’s prey.
Owl pellet dissection is an easy, hands-on way to learn about the eating habits of birds of prey. (Owl pellets are the regurgitated remains of an owl's meal.) But don't be grossed out - finding and piecing together the bones inside owl pellets is fascinating work for a young scientist such as yourself! As you dissect the pellet, you'll find skeletons of mice, voles, birds, and more. Synthetic pellets are available for younger children if you'd like to use a substitute.
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a pellet right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
Materials:
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Click here to go to part:24 Sheep Heart Dissection
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it’s not hard – you can dissect a frog right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
In today’s dissection, we’ll be looking at a frog. Frogs are members of the Class Amphibia. There are many things that make frogs interesting: they live both in water and on land, they actually begin life in water as limbless tadpoles, and some can change color depending on their environment.
Materials
- Frog (click if you need the whole frog kit, or here if you need only the frog)
- Dissection tools
- Dissection pins
- Dissection guide
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Click here to go to part:23 Owl Pellet Dissection
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it’s not hard – you can dissect a crayfish right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
In today’s dissection, we’ll be looking at a crayfish. Crayfish are members of the phylum Arthropoda. There are many things that make crayfish interesting: they dwell at the bottom of streams, rivers, and ponds; they feed on just about anything that comes their way (that’s why they’re called freshwater scavengers); and they have many appendages that help them save energy.
Materials
- Crayfish (click if you need the whole kit, or just the crayfish)
- Dissection tools
- Dissection guide
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Click here to go to part 22:Dissecting a Frog
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it’s not hard – you can dissect a starfish right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
In today’s dissection, we’ll be looking at a starfish. Starfish are members of the phylum Echinoderm. There are many things that make starfish interesting: their rays are symmetrical around their center (this is called radial symmetry), they use seawater instead of blood to transport nutrients through their bodies (this is called a water vascular system), and they move around using tube feet on the underside of their bodies.
Materials
- Starfish (click if you need the whole kit, or just the starfish)
- Dissection tools
- Dissection guide
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Click here to go to part:21 Dissecting a Crayfish
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a fish right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class
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In today’s dissection, we’ll be looking at a perch. Perch are members of the phylum Chordata. There are many things that make perch interesting: they are bony fishes which make them “true” fishes, they live in both freshwater and saltwater, and their diets change based on how big they are.
Materials:
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Click here to go to part 20:Dissecting a Starfish
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a grasshopper right at home using this inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
Materials:
- Grasshopper (click if you need the whole kit or just the grasshopper)
- Dissection tools
- Dissection Guide
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Click here to go to part:19 Perch Dissection
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a worm right at home using an inexpensive specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class
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In today’s dissection, we’ll be looking at an earthworm. Earthworms play an important role in their ecosystem--when they tunnel through dirt they mix nutrients which helps make the soil healthy and able to support plant life.
Materials:
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Click here to go to part:18 Grasshopper Dissection
This experiment is just for advanced students. If you guessed that this has to do with electricity and chemistry, you’re right! But you might wonder how they work together. Back in 1800, William Nicholson and Johann Ritter were the first ones to split water into hydrogen and oxygen using electrolysis. (Soon afterward, Ritter went on to figure out electroplating.) They added energy in the form of an electric current into a cup of water and captured the bubbles forming into two separate cups, one for hydrogen and other for oxygen.
This experiment is not an easy one, so feel free to skip it if you need to. You don’t need to do this to get the concepts of this lesson but it’s such a neat and classical experiment (my students love it) so you can give it a try if you want to. The reason I like this is because what you are really doing in this experiment is ripping molecules apart and then later crashing them back together.
Have fun and please follow the directions carefully. This could be dangerous if you’re not careful. The image shown here is using graphite from two pencils sharpened on both ends, but the instructions below use wire. Feel free to try both to see which types of electrodes provide the best results.
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The shell of chicken eggs are made mostly of calcium carbonate (CaCO3), which which reacts with distilled white vinegar (try placing a raw egg in a glass of vinegar overnight). The shell has over 15,000 tiny little mores that allows air and moisture to pass through, and a protective outer coating to keep out harmful things like dust and bacteria.
We're going to peek inside of an egg and discover the transparent protein membrane (made of the same protein your hair is made up of: keratin) and also peek in the air space that forms when the egg cools and contracts (gets smaller). Can you find the albumen (the egg white)? It's made up of mostly water with about 40 different proteins.
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Download Egg Dissection Lab here for older grades (5-12th) and here for younger grades (K-4).
Click here to go to part 16:Clam Dissection
Going Further
Find the full DNA experiment here.
Click here to go to part 15:Dissecting a Chicken Egg
Click here to go to Part 12: Cells
Find the full Carrot Osmosis experiment here.
Click here to go to Part 14: DNA
Molecules are the building blocks of matter. You’ve probably heard that before, right? But that does it mean? What does a molecule look like? How big are they? Let’s find out.
While you technically can measure the size of a molecule, despite the fact it’s usually too small to do even with a regular microscope, what you can’t do is see an image of the molecule itself. The reason has to do with the limits of nature and wavelengths of light, not because our technology isn’t there yet, or we’re not smart enough to figure it out. Scientists have to get creative about the ways they do about measuring something that isn’t possible to see with the eyes.
Here’s what you do:
Step 1: Place water in the pie pan and sprinkle in the chalk dust. You want a light, even coating on the surface.
Step 2: Place dish soap inside the medicine dropper and hold it up.
Step 3: Squeeze the medicine dropper carefully and slowly so that a single drop forms at the tip. Don’t let it fall!
Step 4: Hold the ruler up and measure the drop. Record this in your data sheet.
Step 5: Hold the tip of the dropper over the pie pan near the surface and let it drop onto the water near the center of the pie pan.
Step 6: Watch it carefully as it spreads out to be one molecule thick!
Step 7: Quickly measure and record the diameter of the layer of the detergent on your data sheet.
Step 8: Use equations for sphere and cylinder volume to determine the height (which we assume to be one molecule thick) of the soap when it’s spread out. That’s the approximate width of the molecule!
What you've done in this experiment is taken a small sphere of soap, and made it flatten itself out to a disk that is one molecule thick. The chalk dust is only there so that you can actually see this happening. When you let the drop hit the surface of the water, due to the structure of the molecules, they repel each other as much as possible. Because of this, we can easily measure the thickness of the soap disk on the surface. The total volume of the drop does not change during the experiment (the act of releasing the drop doesn't change how much soap is in the drop). So the volume of the spherical soap is the same as the volume.
Find the full Measuring the Size of a Molecule experiment here.
Click here to go to Part 13: Osmosis
Click here to go to Part 11: Astrobiology
Find the full Cool Blue Light experiment here.
Click here to go to Part 10: Ecosystems
Click here to go to Part 9: Bioluminescence
Find the full Laser Microscope experiment here.Click here to go to Part 8: Viruses & Bacteria
You basically take small bits of a leaf like spinach, stick it in a cup of water that has extra carbon dioxide in it, and shine a light on it. The plant will take the carbon dioxide from the water and the light from the lamp and make oxygen bubbles that stick to it and lift it to the surface of the water, like a kid holding a bunch of helium balloons. And you time how long this all takes and you have the rate of photosynthesis for your leaf.
Click here to go to Part 7: Taxonomy
Some things you can test (in addition to the ones in the video) include: Sprite, distilled white vinegar, baking soda, Vanish, laundry detergent, clear ammonia, powdered Draino, and Milk of Magnesia. DO NOT mix any of these together! Simply add a bit to each cup and test it with your pH strips. Here's a quick video demonstration:
Click here to go to Part 6: Bonus Content: Measuring Photosynthesis
There are many different kinds of acids: citric acid (in a lemon), tartaric acid (in white wine), malic acid (in apples), acetic acid (in vinegar), and phosphoric acid (in cola drinks). The battery acid in your car is a particularly nasty acid called sulfuric acid that will eat through your skin and bones. Hydrochloric acid is found in your stomach to help digest food, and nitric acid is used to make dyes in fabrics as well as fertilizer compounds.
Click here to go to Part 6: Bonus Content: Plant Color & Chemistry
Click here to go to Part 6: Botany 2
Find the full Gummy Bear experiment here.Click here to go to Part 5: Botany 1
You can learn more about airfoils here, and if you want to learn how to fly a real airplane, go here.Click here to go to Part 4: Birds & Flight
Click here to go to Part 3: Entomology
Dissection in biology provides a hands-on education above and beyond reading a textbook. By seeing, touching and exploring different organs, muscles and tissues inside an animal and seeing how they work together allows you to really understand your own body and appreciate the amazing world around us. And it's not hard - you can dissect a clam right at home using this inexpensive clam specimen with a dissection guide and simple dissection tools! Many doctors, surgeons and veterinarians report that their first fascination with the body started with a biology dissection class.
Materials:
- Fresh clam (in shell)
- Dissection tools
- Clam diagrams
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Click here to go to part 17:Earthworm Dissection
Content coming soon!
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Click here to go to next lesson on Redox reactions
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Click here to download Homework Problem Set #12
Click here for the next lesson in Freezing Point Depression and Boiling Point Elevation.
Click here for next lesson in Partial Pressures.
Let’s get more practice with Henry’s Law, partial pressures, mole fraction, and weight percent with these sample calculations:
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Click here for the next lesson in Colligative Properties Part 2.
Osmosis is how cells allow water to pass through in and out of the cell through a special membrane using a bit of chemistry. Here is how they do it…
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Click here for the next lesson on Colligative Properties Part 1.
Let’s do some sample calculations for the energy of a system that include enthalpy and specific heat.
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Click here to download the Homework Problem Set #7.
Click here to for Homework Problem Set #10
Click here for next lesson on Properties of log and ln.
Click here for the next lesson on Rate Law & Reaction Order Part 2.
Click here for next lesson on Rate Law Part 2
Click here for next lesson in Kinetics Calculations Part 2.
Click here for next lesson in Kinetics Calculations Part 1.
Click here for next lesson in the Arrhenius Equation.
Click here for next lesson on Rate Law & Reaction Order Part 3
Click here for next lesson on Rate Law and Reaction Order Part 1.
Click here for the next lesson on Rate Law Part 1
Supercooling a liquid is a really neat way of keeping the liquid a liquid below the freezing temperature. Normally, when you decrease the temperature of water below 32oF, it turns into ice. But if you do it gently and slowly enough, it will stay a liquid, albeit a really cold one!
In nature, you’ll find supercooled water drops in freezing rain and also inside cumulus clouds. Pilots that fly through these clouds need to pay careful attention, as ice can instantly form on the instrument ports causing the instruments to fail. More dangerous is when it forms on the wings, changing the shape of the wing and causing the wing to stop producing lift. Most planes have de-icing capabilities, but the pilot still needs to turn it on.
We’re going to supercool water, and then disturb it to watch the crystals grow right before our eyes! While we’re only going to supercool it a couple of degrees, scientists can actually supercool water to below -43oF!
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Click here to go to next lesson on Colloids and Polymers
This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too! Learn about the world of rocks, crystals, gems, fossils, and minerals by moving beyond just looking at pretty stones and really being able to identify, test, and classify samples and specimens you come across using techniques that real field experts use. While most people might think of a rock as being fun to climb or toss into a pond, you will now be able to see the special meaning behind the naturally occurring material that is made out of minerals by understanding how the minerals are joined together, what their crystalline structure is like, and much more.
Materials:
- Geology Field Trip in a Bag
- Worksheet printout
- Unglazed porcelain tile (or the bottom of a coffee mug)
- Paper plate or disposable pie pan
- Microscope slide
- Magnifying glass
- Cup of water
- Steel nail
- Double-sided tape
- Magnet
NEW
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First Law of Thermodynamics: Energy is conserved. Energy is the ability to do work. Work is moving something against a force over a distance. Force is a push or a pull, like pulling a wagon or pushing a car. Energy cannot be created or destroyed, but can be transformed.
Materials: ball, string
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Click here to go to next lesson on Combustion.
A battery is a device that produces electrical energy from a chemical reaction. Another name for a battery is voltaic cell. Voltaic means to make electricity.
Most batteries contain two or more different chemical substances. The different chemical substances are usually separated from each other by a barrier. One side of the barrier is the positive terminal of the battery and the other side of the barrier is the negative terminal. When the positive and negative terminals of a battery are connected to a circuit, a chemical reaction takes place between the two different chemical substances that produces a flow of electrons (electricity).
When a battery is producing electricity, one of the chemical substances in the battery loses electrons. These electrons are then gained by the other chemical substance.
A battery is designed so that the electrons lost by one chemical substance are made to flow through a circuit, such as a flashlight lamp, before being gained by the other chemical substance. A battery will produce a flow of electrons until all of the chemical substances involved in the chemical reaction are completely used.
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Click here to go to next lesson on Electrochemistry Analysis
You will be “creating” metallic copper from a solution of copper sulfate and water, and depositing it on a negative electrode. Copper is one of our more interesting elements. Copper is a metal, and element 29 on your periodic table. It conducts heat and electricity very well.
Many things around you are made of copper. Copper wire is used in electrical wiring. It has been used for centuries in the form of pipes to distribute water and other fluids in homes and in industry. The Statue of Liberty is a wonderful example of how beautiful 180,000 pounds of copper can be. Yes, it is made of copper, and no, it doesn’t look like a penny…..on the surface. The green color is copper oxide, which forms on the surface of copper exposed to air and water. The oxide is formed on the surface and does not attack the bulk of the copper. You could say that copper oxide protects the copper.
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Click here for Potassium Permanganate
Magnesium is one of the most common elements in the Earth’s crust. This alkaline earth metal is silvery white, and soft. As you perform this lab, think about why magnesium is used in emergency flares and fireworks. Farmers use it in fertilizers, pharmacists use it in laxatives and antacids, and engineers mix it with aluminum to create the BMW N52 6-cylinder magnesium engine block. Photographers used to use magnesium powder in the camera’s flash before xenon bulbs were available.
Most folks, however, equate magnesium with a burning white flame. Magnesium fires burn too hot to be extinguished using water, so most firefighters use sand or graphite.
We’re going to learn how to (safely) ignite a piece of magnesium in the first experiment, and next how to get energy from it by using it in a battery in the second experiment. Are you ready?
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Click here to go to next lesson on Making Copper
This experiment shows how a battery works using electrochemistry. The copper electrons are chemically reacting with the lemon juice, which is a weak acid, to form copper ions (cathode, or positive electrode) and bubbles of hydrogen.
These copper ions interact with the zinc electrode (negative electrode, or anode) to form zinc ions. The difference in electrical charge (potential) on these two plates causes a voltage.
Materials:
- one zinc and copper strip
- two alligator wires
- digital multimeter
- one fresh large lemon or other fruit
Click here to go to next lesson on Magnesium Battery
Mars is coated with iron oxide, which not only covers the surface but is also present in the rocks made by the volcanoes on Mars.
Today you get to perform a chemistry experiment that investigates the different kinds of rust and shows that given the right conditions, anything containing iron will eventually break down and corrode. When iron rusts, it’s actually going through a chemical reaction: Steel (iron) + Water (oxygen) + Air (oxygen) = Rust
Materials
- Four empty water bottles
- Four balloons
- Water
- Steel wool
- Vinegar
- Water
- Salt
Click here to go to next lesson on Fruit Battery
Never polish your tarnished silver-plated silverware again! Instead, set up a ‘silverware carwash’ where you earn a nickel for every piece you clean. (Just don’t let grandma in on your little secret!)
We’ll be using chemistry and electricity together (electrochemistry) to make a battery that reverses the chemical reaction that puts tarnish on grandma’s good silver. It’s safe, simple, and just needs a grown-up to help with the stove.
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Click here to go to next lesson on Batteries storing energy
If you don’t have equipment lying around for this experiment, wait until you complete Unit 10 (Electricity) and then come back to complete this experiment. It’s definitely worth it!
Electroplating was first figured out by Michael Faraday. The copper dissolves and shoots over to the key and gets stuck as a thin layer onto the metal key. During this process, hydrogen bubbles up and is released as a gas. People use this technique to add material to undersized parts, for place a protective layer of material on objects, to add aesthetic qualities to an object.
Materials:
- one shiny metal key
- 2 alligator clips
- 9V battery clip
- copper sulfate (MSDS)
- one copper strip or shiny copper penny
- one empty pickle jar
- 9V battery
Click here to go to next lesson on Electrochemical cells and voltage
This experiment is just for advanced students. If you guessed that this has to do with electricity and chemistry, you’re right! But you might wonder how they work together. Back in 1800, William Nicholson and Johann Ritter were the first ones to split water into hydrogen and oxygen using electrolysis. (Soon afterward, Ritter went on to figure out electroplating.) They added energy in the form of an electric current into a cup of water and captured the bubbles forming into two separate cups, one for hydrogen and other for oxygen.
This experiment is not an easy one, so feel free to skip it if you need to. You don’t need to do this to get the concepts of this lesson but it’s such a neat and classical experiment (my students love it) so you can give it a try if you want to. The reason I like this is because what you are really doing in this experiment is ripping molecules apart and then later crashing them back together.
Have fun and please follow the directions carefully. This could be dangerous if you’re not careful. The image shown here is using graphite from two pencils sharpened on both ends, but the instructions below use wire. Feel free to try both to see which types of electrodes provide the best results.
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Click here to go to next lesson on Electroplating
Electricity. Chemistry. Nothing in common, have nothing to do with each other. Wrong! Electrochemistry has been a fact since 1774. Once electricity was applied to particular solutions, changes occurred that scientists of the time did not expect.
In this lab, we will discover some of the same things that Farraday found over 300 years ago. We will be there as things tear apart, particles rush about, and the power of attraction is very strong. We’re not talking about dancing, we’re talking about something much more important and interesting….we’re talking about ELECTROCHEMISTRY!
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Click here to go to next lesson on Electrolysis
If you guessed that electrochemistry has to do with electricity and chemistry, you’re right! But you might wonder how they work together. Back in 1800, William Nicholson and Johann Ritter were the first ones to split water into hydrogen and oxygen using electrolysis. (Soon afterwards, Ritter went on to figure out electroplating.) They added energy in the form of an electric current into a cup of water and captured the bubbles forming into two separate cups, one for hydrogen and other for oxygen.
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Click here to go to next lesson on More on Electrochemistry
This is a cool video from a Teacher’s Educational Channel in Europe I thought you might enjoy about the science of fireworks:
You can view the full video here.
Click here to go to your next lesson in Electrochemistry.
Charcoal crystals uses evaporation to grow the crystals, which will continue to grow for weeks afterward. You’ll need a piece of very porous material, such as a charcoal briquette, sponge, or similar object to absorb the solution and grow your crystals as the liquid evaporates. These crystals are NOT for eating, so be sure to keep your growing garden away from young children and pets! This project is exclusively for advanced students, as it more involves toxic chemicals than just salt and sugar.
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Click here to go to next lesson on Science of Fireworks
Potassium perchlorate is usually safer than chlorate salt, but it sometimes is hard to get it. In the past, the only supplier in the US makes ammonium perchlorate, the oxidizer that was used with the space shuttle booster rockets, and each shuttle launch required 1.5 million pounds of it, which was twice the annual consumption rate, so when there were a lot of shuttle launches, the fireworks market took a hit and it was near impossible to get any potassium perchlorate.
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Click here to go to next lesson on Charcoal Crystals
Second Law of Thermodynamics: Heat flows from hot to cold. Heat is the movement of thermal energy from one object to another. Heat can only flow from an object of a higher temperature to an object of a lower temperature. Heat can be transferred from one object to another through conduction, convection and radiation.
Temperature is basically a speedometer for molecules. The faster they are wiggling and jiggling, the higher the temperature and the higher the thermal energy that object has. Your skin, mouth and tongue are antennas which can sense thermal energy. When an object absorbs heat it does not necessarily change temperature.
Materials: hot cup of cocoa
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Click here to go to next lesson on Fireworks
First Law of Thermodynamics: Energy is conserved. Energy is the ability to do work. Work is moving something against a force over a distance. Force is a push or a pull, like pulling a wagon or pushing a car. Energy cannot be created or destroyed, but can be transformed.
Materials: ball, string
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Click here to go to next lesson on Thermodynamics: Second law
What do you do if you don’t know the concentration of a solution? We use a method called titration to determine how many moles are present in the solution of an acid or a base by neutralizing it. A titration curve is when you graph out the pH as you drop it in the solution.
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Click here to go to next lesson on pH and solubility
This experiment is for advanced students. All chemical reactions are equilibrium reactions. This experiment is really cool because you’re going to watch how a chemical reaction resists a pH change.
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Click here to go to next lesson on Titrations and pH curves
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Click here to go to next lesson on Potassium Hexacynoferrate
If you love the idea of mixing up chemicals and dream of having your own mad science lab one day, this one is for you. You are going to mix up each solid with each liquid in a chemical matrix.
In a university class, one of the first things you learn in chemistry is the difference between physical and chemical changes. An example of a physical change happens when you change the shape of an object, like wadding up a piece of paper. If you light the paper wad on fire, you now have a chemical change. You are rearranging the atoms that used to be the molecules that made up the paper into other molecules, such as carbon monoxide, carbon dioxide, ash, and so forth.
How can you tell if you have a chemical change? If something changes color, gives off light (such as the light sticks used around Halloween), or absorbs heat (gets cold) or produces heat (gets warm), it’s a chemical change.
What about physical changes? Some examples of physical changes include tearing cloth, rolling dough, stretching rubber bands, eating a banana, or blowing bubbles.
About this experiment: Your solutions will turn red, orange, yellow, green, blue, purple, hot, cold, bubbling, foaming, rock hard, oozy, and slimy, and they’ll crystallize and gel — depending on what you put in and how much!
This is the one set of chemicals that you can mix together without worrying about any lethal gases. I do recommend doing this OUTSIDE, as the alcohol and peroxide vapors can irritate you. Always have goggles on and gloves on your hands, and a hose handy in case of spills. Although these chemicals are not harmful to your skin, they can cause your skin to dry out and itch. Wear gloves (latex or similar) and eye protection (safety goggles), and if you’re not sure about an experiment or chemical, just don’t do it. (Skip the peroxide and cold pack if you have small kids.)
Materials:
• sodium tetraborate (borax, laundry aisle)
• sodium bicarbonate (baking soda, baking aisle)
• sodium carbonate (washing soda, laundry aisle)
• calcium chloride (AKA “DriEz” or “Ice Melt”)
• citric acid (spice section, used for preserving and pickling)
• ammonium nitrate (single-use disposable cold pack)
• isopropyl rubbing alcohol
• hydrogen peroxide
• acetic acid (distilled white vinegar)
• water
• liquid dish soap (add to water)
• muffin tin or disposable cups
• popsicle sticks for stirring and mixing
• tablecloths (one for the table, another for the floor)
• head of red cabbage (indicator)
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Phenolphthalein is a weak, colorless acid that changes color when it touches acidic (turns orange) or basic (turns pink/fuchsia) substances. People used to take it as a laxative (not recommended today, as ingesting high amounts may cause cancer). Use gloves when handling this chemical, as your skin can absorb it on contact. I’ll show you how:
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You can go your whole life without paying any attention to the chemistry behind acids and bases. But you use acids and bases all the time! They are all around you. We identify acids and bases by measuring their pH.
Every liquid has a pH. If you pay particular attention to this lab, you will even be able to identify most acids and bases and understand why they do what they do. Acids range from very strong to very weak. The strongest acids will dissolve steel. The weakest acids are in your drink box. The strongest bases behave similarly. They can burn your skin or you can wash your hands with them.
Acid rain is one aspect of low pH that you can see every day if you look for it. This is a strange name, isn’t it? We get rained on all the time. If people were dissolving, if the rain made their skin smoke and burn, you’d think it would make headlines, wouldn’t you? The truth is acid rain is too weak to harm us except in very rare and localized conditions. But it’s hard on limestone buildings.
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You can go your whole life without paying any attention to the chemistry behind acids and bases. But you use acids and bases all the time! They are all around you. We identify acids and bases by measuring their pH.
Every liquid has a pH. If you pay particular attention to this lab, you will even be able to identify most acids and bases and understand why they do what they do. Acids range from very strong to very weak. The strongest acids will dissolve steel. The weakest acids are in your drink box. The strongest bases behave similarly. They can burn your skin or you can wash your hands with them.
Acid rain is one aspect of low pH that you can see every day if you look for it. This is a strange name, isn’t it? We get rained on all the time. If people were dissolving, if the rain made their skin smoke and burn, you’d think it would make headlines, wouldn’t you? The truth is acid rain is too weak to harm us except in very rare and localized conditions. But it’s hard on limestone buildings.
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The seven strong acids are: hydrochloric acid (HCl), nitric acid (HNO3) used in fireworks and explosives, sulfuric acid (H2SO4) which is the acid in your car battery, hydrobromic acid (HBr), hydroiodic acid (HI), and perchloric acid (HClO4). The record-holder for the world’s strongest acid are the carborane (CAR-bor-ane) superacids (over a million times stronger than concentrated sulfuric acid).
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Click here to download Homework Problem Set #11.
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Strong acids and strong bases (which we’ll talk about in a minute) all have one thing in common: they break apart (completely dissociate) into ions when placed in water. This means that once you dunk the acid molecule in water, it splits apart and does not exist as a whole molecule in water. Strong acids form H+ and a negative ion
The seven strong acids are: hydrochloric acid (HCl), nitric acid (HNO3) used in fireworks and explosives, sulfuric acid (H2SO4) which is the acid in your car battery, hydrobromic acid (HBr), hydroiodic acid (HI), and perchloric acid (HClO4). The record-holder for the world’s strongest acid are the carborane (CAR-bor-ane) superacids (over a million times stronger than concentrated sulfuric acid).
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First discovered in 1886 by Hans Heinrich Landolt, the iodine clock reaction is one of the best classical chemical kinetics experiments. Here’s what to expect: Two clear solutions are mixed. At first there is no visible reaction, but after a short time, the liquid suddenly turns dark blue.
Usually, this reaction uses a solution of hydrogen peroxide with sulfuric acid, but you can substitute a weaker (and safer) acid that works just as well: acetic acid (distilled white vinegar). The second solution contains potassium iodide, sodium thiosulfate (crystals), and starch (we’re using a starch packing peanut, but you can also use plain old cornstarch). Combine one with the other to get the overall reaction, but note that there are actually two reactions happening simultaneously.
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Chemical equilibrium is the condition that happens when the concentration of the reactants and products don’t have any net change over time. This doesn’t mean that the reaction stops, just that the producing and consuming of the molecules is in balance.
Most chemical reactions are reversible, just like phases changes. Do you remember the hot icicle experiment? Do you remember how to get it back to the starting point? You have to add energy to the solid sodium acetate to turn it back into a liquid, so it can turn back into a solid again. Then let that experiment sit for a bit (overnight or about 12 hours) and in the morning, you’ll have crystals growing on your pipe cleaner. Now if you want to reverse this reaction, all you have to do is add energy to the system and the crystals will dissolve back into the solution. You can heat it up in the microwave or in a pot of water on the stove, and the crystals will disappear.
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Chemical equilibrium is the condition that happens when the concentration of the reactants and products don’t have any net change over time. This doesn’t mean that the reaction stops, just that the producing and consuming of the molecules is in balance.
Most chemical reactions are reversible, just like phases changes. Do you remember the hot icicle experiment? Do you remember how to get it back to the starting point? You have to add energy to the solid sodium acetate to turn it back into a liquid, so it can turn back into a solid again. Then let that experiment sit for a bit (overnight or about 12 hours) and in the morning, you’ll have crystals growing on your pipe cleaner. Now if you want to reverse this reaction, all you have to do is add energy to the system and the crystals will dissolve back into the solution. You can heat it up in the microwave or in a pot of water on the stove, and the crystals will disappear.
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Chemists want to control not only what comes out of a chemical reaction, but how fast the reaction occurs. For example, scientists are working to slow down the depletion rate of the ozone in the upper level of our atmosphere, so we stay protected from harmful UV rays.
The rate of the chemical reaction of a nail rusting is slow compared to how fast baking soda reacts with vinegar. Different factors affect the speed of the reaction, but the main idea is that the more collisions between particles, the faster the reaction will take place.
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