Peristalsis is the wavelike movement of muscles that move food through your gastrointestinal tract. The process of digestion begins with chewing and mixing the food with saliva. From there, the epiglottis opens up to deposit a hunk of chewed food (called bolus) into your esophagus – this is the tube that runs from your mouth to your stomach. Since the esophagus is so skinny, the muscles along it must expand and contract in order to move food down. In this activity we will examine that process.


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Everything living produces some sort of odor. Flowers use them to entice bees to pollinate them. We know that the tastes of foods are enhanced by the way that they smell. As humans, each of us even has own unique odor.


In this lab, we look at the diffusion of scents. They start in one place, but often end up spread around the room and can be detected by many people.


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In this experiment, we will continue to explore Ruffini’s endings in your skin. We also look at your body’s ability to detect temperature and regulate its own temperature. You will study how the body cools and warms itself.


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Voluntary nerves are the ones that are under our direct control. Others, called involuntary nerves, are under the control of our brains and create involuntary reactions.


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Your eyes have two different light receptors located on the back of the eyeball. These are the rods, which see black, white and grays, and the cones, which see color. In order to adapt to the dark, our eyes make a chemical called visual purple. This helps the rods to see and transmit what you see in situations where there is little light.


Your pupils also increase in diameter in the darkness. This allows for a slight increase in the amount of light entering your eye. This combination of visual purple and more light makes it possible for you to see in darker situations.


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Levers are classified into three types: first class, second class, or third class. Their class is identified by the location of the load, the force moving the load, and the fulcrum. In this activity, you will learn about the types of levers and then use your body to make each type.


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Sound has the ability to travel through the states of matter: solids, liquids, and gases. In this experiment we will study the movement of sound through these three states.


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You know that sound comes from vibration which are picked up by the pinna (external part of the ears). Then the vibrations vibrate your tympanic membrane, which in turn vibrates the ossicles and then the cochlea. The cochlea sends information through the auditory nerve and sends it to the brain, which recognizes it as sound.


In this lab, you will testing your ability to sort and match different sounds.


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Have you ever held a plastic ruler over the edge of a desk or table and whacked the end of it? If so, you would notice a funny sound. This sound changes if you change the length of the ruler that is hanging over the edge. The sound you hear is made by the ruler’s vibrations.


In this lab, we begin to learn about sound. You know it is collected and deciphered by your ears, but did you also know that all sound is made when something vibrates? It could be a guitar string, vocal chords in your throat, or a plastic ruler that is hanging over the edge of the desk: vibrations make sound.


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How do you think animals know we’re around long before they see us? Sure, most have a powerful sense of smell, but they can also hear us first. In this activity, we are going to simulate enhanced tympanic membranes (or ear drums) by attaching styrofoam cups to your ears. This will increase the number of sound waves your ears are able to capture.


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Some groups of muscles are stronger than others because each group is designed for a different and specific function. It just makes sense that the muscle groups in our legs would need to be stronger than the ones in our toes.


For this experiment, you will use a bathroom scale to test the strength of various muscle groups.


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The skeleton is your body’s internal supporting structure. It holds everything together. In addition to providing support, bones act as shock absorbers when you jump, fall, and run. Bones have big responsibilities and so they must be really strong. They also need to be arranged properly for the best support and shock absorption.


In this experiment, we will look at the internal arrangement of the bones holding together your body.


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Our sense of touch provides us with information that helps us to process and explore our world. Nerves play an important part in the sense of touch by being the wires that carry signals from the skin to the brain. But the body has a plan in place so that our brains don’t get overwhelmed with too much information. This plan is a lot like a blueprint for wiring a house. Just like a house has light switches and electrical outlets in strategic locations, our bodies have touch receptors of various numbers based on their location. In this lab, we will explore an arm to determine where the highest concentrations of nerves are in that limb.


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Involuntary responses are ones that you can’t control, but they are usually in place to help with survival. One good example is when you touch something hot. Your hand does not take the time to send a message to your brain and then have the brain tell your hand to pull away. By then, your hand might be seriously hurt! Instead, your body immediately removes your hand in order to protect it from further harm.


Today you will test an involuntary reflex by using the tendon reflex test. A thick, rubbery band called the patellar tendon holds your knee cap in place. Having one leg on top of the other not only stretches the tendon, but it also makes it possible to see a reaction. You can test the reflex by giving your tendon a tap and watching what happens.


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The buildup of things like food and bacteria where your gums and teeth meet, and also between your teeth, is called plaque. Where plaque lives is also where the bacteria turns the sugar in your mouth into harmful acids that attack your teeth’s enamel and can lead to gum disease. Regular brushing is a great way to remove plaque and keep your mouth healthy.


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Without the sun, there would be no life on Earth. The sun warms the earth, generates wind, and carries water into the air to produce rain and snow. The energy of the sun provides sunlight for all the plant life on our planet, and through plants provides energy for all animals.


The sun is like a giant furnace in which hydrogen nuclei (atoms without electrons) are constantly smashed together to form helium nuclei. This process is called nuclear fusion. In this process, 3.6 billion kilograms (8 billion pounds) of matter are converted to pure energy every second. The temperature in the sun exceeds 15 million degrees.


Nuclear fusion is one kind of energy. Other forms of energy include: mechanical energy, heat, electrical energy, chemical energy, and light. Mechanical energy is the energy of organized motion, such as a turning wheel. Heat is the energy of random motion, such as a cup of hot water. Electrical energy is the energy of moving charged particles or electrons, such as a current in a wire. Chemical energy is the energy stored in bonds that hold atoms together. Light is any form of electromagnetic waves, such as X rays, microwaves, radio waves, ultraviolet light, or visible light.


Energy can be converted from one from to another. For example, the nuclear energy of the sun is converted to light, which goes through space to the earth. Solar collectors of mirrors can be used to focus some of that light to heat water to steam. This steam can be used to turn a turbine, which can power a generator to produce electricity.


Most of our energy needs are met by burning fossil fuels such as coal, oil, gasoline, and natural gas. The chemical energy stored in these substances is released by burning these fuels. When fossil fuels burn, they combine with oxygen in the air and produce heat and light.


Fossil fuels are not renewable. When they are used up, they are gone forever. However, renewable energy sources such as wind, sun, geothermal, biomass and water power are renewable. They can be used over and over to generate the energy to run our society.


Tremendous amounts of renewable energy are available. For example, the solar energy that falls on just the road surfaces in the United States is equal to the entire energy needs of the country. Although there are sufficient amounts of renewable energy, we must improve our methods of collecting, concentrating, and converting renewable energy into useful forms.


In the following experiments, you will learn something about the amount of energy the sun produces at the earth’s surface and how heat energy can be stored.
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Temperature is a measure of the average hotness of an object. The hotter an object, the higher its temperature. As the temperature is raised, the atoms and molecules in an object move faster. The molecules in hot water move faster than the molecules in cold water. Remember that the heat energy stored in an object depends on both the temperature and the amount of the substance. A smaller amount of water will have less heat energy than a larger amount of water at the same temperature.


Increasing the temperature of a large body of water is one way to store heat energy for later use. A large container filled with salt water, called brine, may be used to absorb heat energy during the day when it is warm. This energy will be held in the salt water until the night when it is cooler. This stored heat energy can be released at night to warm a house or building. This is one way to store the sun’s heat energy until it is needed.


Solar ponds are used to store energy from the sun. Temperatures close to 100°C (212°F) have been achieved in solar ponds. Solar ponds contain a layer of fresh water above a layer of salt water. Because the salt water is heavier, it remains at the bottom of the pond-even as it gets quite hot. A black plastic bottom helps absorb solar energy from sunlight. The water on top serves to insulate and trap the heat in the pond.


In a fresh water pond, as the water on the bottom is heated from sunlight, the hot water becomes lighter and rises to the top of the pond. This convection or movement of hot water to the top tends to carry away excess heat. However, in a salt water pond, there is no convection so heat is trapped. In Israel a series of salt water, solar ponds were developed around the Dead Sea. The heat stored in these solar ponds has been used to run turbines and generate electricity.
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The United States has large reserves of coal, natural gas, and crude oil which is used to make gasoline. However, the United States uses the energy of millions of barrels of crude oil every day, and it must import about half its crude oil from other countries.


Burning fossil fuels (oil, coal, gasoline, and natural gas) produces carbon dioxide gas. Carbon dioxide is one of the main greenhouse gases that may contribute to global warming. In addition, burning coal and gasoline can produce pollution molecules that contribute to smog and acid rain.


Using renewable energy-such as solar, wind, water, biomass, and geothermal-could help reduce pollution, prevent global warming, and decrease acid rain. Nuclear energy also has these advantages, but it requires storing radioactive wastes generated by nuclear power plants. Currently, renewable energy produces only a small part of the energy needs of the


United States. However, as technology improves, renewable energy should become less expensive and more common.


Hydropower (water power) is the least expensive way to produce I electricity. The sun causes water to evaporate. The evaporated water falls to the earth as rain or snow and fills lakes. Hydropower uses water stored in lakes behind dams. As water flows through a dam, the falling water turns turbines that run generators to produce electricity.


Currently, geothermal energy (heat inside the earth), biomass (energy from plants), solar energy (light from concentrated sunlight), and wind are being used to generate electricity. For example, in California there are more than sixteen thousand (16,000) wind turbines that generate enough power to supply a city the size of San Francisco with electricity.


In addition to producing more energy, we can also help meet our energy needs through conservation. Conservation means using less energy and using it more efficiently.


In the following experiments, you will use wind to do work, examine how batteries can store energy, and see how insulation can save energy.
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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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An insulator is a substance that partly blocks or slows the flow of heat through it. Styrofoam is a lightweight plastic used in drinking cups. Styrofoam is a good insulator. A cooler or ice chest that is made of Styrofoam or some other insulator tends to block the flow of heat through it.


Heat flows into buildings during warm summer months and from buildings during cold winter months. Energy must be used to cool buildings in the summer and heat them in the winter. Since insulation can slow the flow of heat, the use of insulation in buildings can save energy.


Some common home and building insulation materials include Styrofoam, polyurethane foam, and fiberglass. These materials are all good insulators, which means that they are poor conductors of heat. Placing these insulating materials on attic floors or in building walls tends to trap heat inside during the cold winter and keep heat out during the hot summer.


Plastic foams filled with trapped gas tend to block heat flow. The chemicals used to make polyurethane foam can be sprayed directly into the spaces between walls. These chemicals produce carbon dioxide gas and polyurethane plastic. The gas tends to spread the polymer apart so the weight is mostly plastic but the volume is mostly trapped gas. Polyurethane also is used to insulate refrigerators, refrigerated trucks, pipes, and building walls.


Fiberglass insulation is frequently used in attic floors to insulate homes. Also, fiberglass insulation is used to insulate the Trans-Alaska pipeline. This pipe carries oil 800 miles from Prudhoe Bay in northern Alaska to Valdez in southern Alaska. The crude oil that travels through this pipe is easier to pump if it is hot. An insulated pipeline requires less energy to keep the oil hot.


Energy conservation becomes more and more important as energy costs rise. A great deal of energy is used to cool buildings in summer and heat buildings in winter. Less energy will be needed if buildings are well insulated and energy is not wasted.
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Cooling and heating are opposite processes. Cooling is the removal of heat energy from an object or space and heating is the addition of heat energy to an object or space. We use these opposite processes a great deal in our daily lives. For example, in the kitchen we use the cooling provided by a refrigerator to keep food cold. We also use the heat from a stove to cook food.


Nearly 75 percent of the energy used by the average family household in the United States goes for cooling and heating purposes. Air conditioning and refrigeration are the major cooling requirements of a home, while water and space heating are the most important heating requirements.


In the experiments that follow you will learn more about cooling and heating. You will also learn alternative ways of cooling and heating, using such unusual materials as gases, salts, water, and trees.
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Having shade trees around a house can decrease the cost of cooling the house with air conditioning. A house not shaded from the sun absorbs some of the light from the sun and heats up the outside surface of the house. If the house is poorly insulated, some of this heat will penetrate into the house, heating up the inside. The air conditioner will use more energy to remove this added heat.


Properly designed roof overhangs can significantly decrease the heating and cooling costs of a house. Because the earth’s axis is tilted, the sun is lower in the winter in the northern hemisphere. In the summer, the sun is higher in the sky. A properly designed roof overhang allows sunlight in the winter to shine through windows and warm the furnishings in the rooms that receive the direct sunlight. This reduces the heating cost in the winter. In the summer, the overhang blocks the sunlight from shining into the window and heating the furnishings. This reduces the cooling cost in the summer.
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The evaporation of water for cooling purposes is called evaporative cooling. An important example of this type of cooling is the removal of body heat by humans through sweating. When your body needs to cool, perspiration is released to the surface of your skin where it evaporates. The evaporation of the water in the perspiration causes your skin to cool.


Breezes feel particularly cooling when you have perspiration on your skin. This is because the increased movement of air over your body evaporates more water from your skin than still air does. Water on your skin evaporates more slowly when the humidity is high. This is because the humid air already contains much water vapor. Humid air absorbs less water as vapor than dry air.


Electrical power plants that burn fossil fuels or use nuclear energy to generate electricity use huge water cooling towers for cooling purposes. The water to be cooled is pumped to the top of the tower and allowed to drip down through the tower. As the water moves down the tower, air from the bottom of the tower moves up through the tower, evaporating some of the falling water. The heat lost by the evaporating water cools the remaining water that is collected in a basin under the tower. One pound of water that evaporates in a tower can lower the temperature of 100 pounds (45 kilograms) of other water by nearly 50°C (100°F).
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In a typical air conditioning or refrigeration system, a liquid at high pressure is allowed to pass through a valve from a higher pressure to a lower pressure. As the liquid enters the lower pressure region, it changes from a liquid to a gas. This change causes a cooling effect. The liquid cools as it changes to a gas.


In a cooling system, such as a refrigerator or air conditioner, this cold gas is used to cool a box (refrigerator) or a room (air conditioner). Then the cool gas is forced through a compressor pump where it undergoes a warming effect and changes back to a liquid. This excess heat is removed before the liquid is expanded to a gas again. In an air conditioner, the excess heat is blown outside.


Special molecules containing chlorine, fluorine, and carbon atoms are used in most cooling systems. These Freon or chlorofluorocarbon (CFC) molecules are used because they are stable, nontoxic, and will not burn.


In recent years, scientists have discovered that these Freon or CFC molecules are damaging the earth’s ozone layer. Ozone molecules in the upper atmosphere block harmful ultraviolet radiation from reaching the earth. Because these CFC molecules are so stable they tend to stay in the atmosphere for many years, during which time they gradually spread to the upper atmosphere.


In the upper atmosphere, CFC molecules can release chlorine atoms. These atoms cause a chemical reaction that breaks apart ozone. One chlorofluorocarbon molecule may destroy thousands of ozone molecules. Scientists and engineers are looking for new methods of cooling and new gases that are less damaging to the ozone layer.


The main energy used in operating a cooling system is the energy required to run a compressor to force a gas to a higher pressure, where it will change back to a liquid. This energy is normally supplied by electricity or by burning natural gas to run a compressor pump. However, there are systems in which solar energy is used to supply the energy needed for cooling.
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The energy of sunlight powers our biosphere (air, water, land, and life on the earth’s surface). About 50 percent of the solar energy striking the earth is converted to heat that warms our planet and drives the winds. About 30 percent of the solar energy is reflected directly back into space. The water cycle (evaporation of water followed by rain or snow) is powered by about 20 percent of the solar energy.


Some of the sunlight that reaches the earth is used by plants in photosynthesis. Plants containing chlorophyll use photosynthesis to change sunlight to energy. Since these green plants form the base of the food chain, all plants and animals depend on solar energy for their survival.


When the sun is overhead, about 1,000 watts of solar power strike 1 square meter (10.8 square feet) of the earth’s surface. Using solar cells, this solar energy can be converted to electricity. However, because sunlight cannot be converted completely to electricity, it takes at least a square meter of area to gather enough sunlight to run a 100-watt light bulb.


Solar energy is still more expensive than other methods of generating electricity. However, the cost of solar electricity has greatly decreased since the first solar cells were developed in 1954.


It has been proposed that panels of solar cells on satellites in orbit above the earth could convert solar energy to electricity twenty-four hours a day. These huge solar power satellites could convert electrical energy to microwaves and then beam these microwaves to Earth. At the earth’s surface, tremendous fields covered with antennas could convert the microwave energy back to electricity.


It would take thousands of astronauts many years to build such a complicated system. However, there are many practical uses of solar energy in use today. These uses include heating water, heating and cooling buildings, producing electricity from solar cells, and using rain and snow from the water cycle to power electrical generators at dams.


In the following experiments, you will examine the use of solar energy in heating water, .cooking foods, concentrating sunlight, and producing electricity.
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Cooking involves heating food to bring about chemical changes. Sometimes foods are heated simply because the food tastes better warm than cold. In making tea, we sometimes heat water to help dissolve tea or help dissolve sugar if the tea is sweetened.


Normally the water used to make tea is heated on a range top or in a microwave oven. Using a range or microwave oven requires buying energy in the form of electricity or natural gas. Using a solar cooker does not require any energy costs because it uses a freely available renewable energy source-the sun.


A curved mirror in a bowl-like shape can focus reflected sunlight at a spot for cooking. A mirror about 1.5 meters (5 feet) across can generate a temperature of 177°C (350°F) and boil a liter of water in about fifteen minutes. In sunny areas of the world, solar cookers can be used instead of burning firewood for cooking.


Another way reflected and focused sunlight is used is to generate electricity. In southern California in 1982, a solar-thermal plant was built that can generate ten million watts of electrical power. This plant consists of 1,818 mirrored heliostats. A heliostat is a device that moves to track the sun across the sky and to reflect the sunlight at the same point. Each heliostat has twelve mirrors, and all the heliostats reflect sunlight to the same spot. The reflected light is directed at the top of a 90-meter (295-foot) tall tower. The concentrated sunlight is used to boil water and heat the steam up to 560° C (1,040 ° F). The steam turns a turbine that powers a generator to produce electricity.


One obvious disadvantage of solar-thermal plants is that they only operate when the sun is shining. The heat energy can be stored for a time by heating up a liquid or melting salt. Or the energy can be used to break water into hydrogen and oxygen. The hydrogen can then be stored and burned later to produce water and release energy.
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Materials


  • Three clear, clean plastic cups
  • Two small tea bags
  • Aluminum foil
  • Watch or clock
  • Measuring cup
  • Water
  • Two spoons
  • White sheet of paper
  • Plastic pan (4 inches deep and 12 inches across is a convenient size but other sizes can be used)


Download Student Worksheet & Exercises


Procedure


You will need to do this experiment on a warm, sunny day.


Use two sheets of aluminum foil and place them crosswise to completely cover the bottom and sides of a plastic pan. Try to arrange the aluminum foil so that it is smooth and curved like a bowl. The aluminum foil will help to reflect the solar energy and concentrate the light and heat toward the center of the pan. Place this aluminum covered pan outside in a warm, sunny spot where the sunlight will shine directly on it.


Add one cup of water to each of two plastic cups. The water you add to the cups should be neither hot nor cold, but about temperature. Place one cup of water in the middle of the pan. Turn the empty plastic cup upside down and place it on top of this cup. Leave this “solar cooker” undisturbed for one hour. The other cup of water should remain inside.


After one hour, gently place one tea bag in each of the water-filled cups. Wait ten minutes and then lift the tea bag out of each cup. Using a spoon, stir each cup of tea. Place both cups of tea on a white piece of paper and look down on the two cups to compare their darkness. Put your finger in each cup of tea to compare their temperatures.


Observations


Which cup of tea is a darker color? Which cup of tea is warmer?


Discussion


You should find that the water left in the “solar cooker” is darker and warmer than the water left in the shade. The darker color indicates that more tea has gone into or dissolved in the warmer water.


Other Things to Try


Place your “solar cooker” in the sun as in this experiment, but place one plastic cup upside down in the middle of the pan. Put a pat of margarine or butter on top of this cup. Will the sun melt this butter? How long does it take to melt? Repeat this activity with a piece of soft cheese and determine if the solar heater will melt the cheese. In a more carefully made solar cooker, the reflective surfaces are angled to focus a large amount of sunlight in one spot and the temperatures obtained are much higher than in your cooker.


Set one cup of water in your “solar cooker.” Set a second cup of water in the sunshine and leave both cups for one hour. Use a thermometer to check the temperature of each cup of water. Does your “solar cooker” help focus the sun’s rays and increase the temperature?


Exercises Answer the questions below:


  1. What type of solar energy are we seeing in this experiment?
    1. Solar fusion
    2. Solar voltaic
    3. Solar thermal
    4. Radiation potential
  2. Name two ways that the earth’s systems depend on the sun:
  3. What is one advantage of solar thermal energy? What is one disadvantage?
    1. Advantage:
    2. Disadvantage:

The curved shape of the magnifying lens causes light rays to bend and focus on an image. When we look through the lens, we can use it to make writing or some other object appear larger. However, the magnifying lens can also be used to make something smaller. The light from the bulb is bent and focused on the wall when the lens is held far from the lamp and close to the wall. The image is much brighter than the surroundings. This is because all the light falling on the surface of the lens is concentrated into a much smaller area.


When sunlight is concentrated by passing it through a lens, the result can be an intensely bright and not spot of light. Even a small magnifying glass can increase the intensity of the sun enough to set wood and paper on fire. We are using a light bulb rather than sunlight for this experiment because concentrated sunlight Can be very harmful to your eyes. NEVER LOOK AT A CONCENTRATED IMAGE OF THE SUN.


The United States Department of Energy’s National Renewable Energy Laboratory in Colorado uses solar energy to operate a special furnace. This high-temperature solar furnace uses a lens to concentrate sunlight. A heliostat (a device used to track the motion of the sun across the sky) is used so that the image reflected from a mirror is always directed at the same spot. The lens is used to concentrate sunlight from a mirror to an area about the size of a penny. This concentrated sunlight has the energy of 20,000 suns shining in one spot.


In less than half a second, the temperature can be raised to 1,720° C (3,128° F) which is hot enough to melt sand. This high-temperature solar furnace is being used to harden steel and to make ceramic materials that must be heated to extremely high temperatures.


Concentrated sunlight also has been used to purify polluted ground water. The ultraviolet radiation in sunlight can break down organic pollutants into carbon dioxide, water, and harmless chlorine ions. This procedure has been successfully carried out at the Lawrence Livermore Laboratory in California. In the laboratory, up to 100,000 gallons of contaminated water could be treated in one day.
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The solar cell you are using for this experiment is made from the element silicon. Silicon solar cells consist of two thin wafers of treated silicon that are sandwiched together. The treated silicon is made by first melting extremely pure silicon in a special furnace. Tiny amounts of other elements are added which produce either a small positive or negative electrical charge.


Usually boron is added to produce a positive charge and phosphorus is added to produce a negative charge. The addition of these other elements to pure silicon to produce an electrical charge is called doping.


After being doped, the molten silicon is allowed to cool. As it cools, the doped silicon grows into a large crystal from which very thin wafers are cut. A wafer cut from a large crystal of silicon doped with boron is called the positive or P-layer because it has a positive charge. A wafer cut from a large crystal of silicon doped with phosphorous is called the negative or N-layer.


To make a solar cell, a positive wafer (P-layer) and a negative wafer (N-layer) are sandwiched together. This causes the P-layer to develop a slight positive charge, and the N-layer to develop a slight negative charge. The solar cell is connected to a circuit by wires leading from the P-layer and the N-layer. When light falls on the surface of the cell, electrons are made to move from one layer to the other. Thus, a current of electricity flows through the circuit.


The first solar cells provided electrical power for space satellites and vehicles. Satellites and space vehicles are still big users of solar cells. Solar cells are now being used to provide electrical power for calculators and similar devices, weather stations in remote areas, oil-drilling platforms, and remote communication relay stations.


The best silicon cells convert only a small portion of the sunlight striking the cells into electricity. The efficiency of solar cells is about 15 percent. This means that 15 percent of the sunlight that strikes the cell is converted into electrical energy. The sunlight that is not converted into electricity either reflects off the surface of the cell or is converted into heat energy.
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Fossil fuels, which include petroleum, natural gas, and coal, supply nearly 90 percent of the energy needs of the United States and other industrialized nations. Because of their high demand, these nonrenewable energy resources are rapidly being consumed. Coal supplies are expected to last about a thousand years.


We must find other sources of energy to meet the increasing fuel demands of modern society. Important alternate sources of energy include: solar, wind, biomass, hydroelectric, geothermal, nuclear, and tidal energy.


One of the benefits of using alternate sources of energy is that many of them are “clean.” This means that they do not cause pollution. Also, many alternative energy sources are renewable energy sources. They are replaced naturally-such as plant life-or are readily available – such as the sun and wind. In addition, the use of renewable forms of energy will allow us to stretch out our current supply of fossil fuels so they will last longer.


In this chapter you will learn how biomass, or organic matter, can be an important energy source. Plants are the most important biomass energy source. Plant material can be burned directly-as with wood-or it can be converted into a fuel by other means. In the experiments that follow you will explore: how water can be heated by composting grass, how a peanut burns, and how corn syrup can be made into ethyl alcohol.
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A peanut is not a nut, but actually a seed. In addition to containing protein, a peanut is rich in fats and carbohydrates. Fats and carbohydrates are the major sources of energy for plants and animals.


The energy contained in the peanut actually came from the sun. Green plants absorb solar energy and use it in photosynthesis. During photosynthesis, carbon dioxide and water are combined to make glucose. Glucose is a simple sugar that is a type of carbohydrate. Oxygen gas is also made during photosynthesis.


The glucose made during photosynthesis is used by plants to make other important chemical substances needed for living and growing. Some of the chemical substances made from glucose include fats, carbohydrates (such as various sugars, starch, and cellulose), and proteins.


Photosynthesis is the way in which green plants make their food, and ultimately, all the food available on earth. All animals and nongreen plants (such as fungi and bacteria) depend on the stored energy of green plants to live. Photosynthesis is the most important way animals obtain energy from the sun.


Oil squeezed from nuts and seeds is a potential source of fuel. In some parts of the world, oil squeezed from seeds-particularly sunflower seeds-is burned as a motor fuel in some farm equipment. In the United States, some people have modified diesel cars and trucks to run on vegetable oils.


Fuels from vegetable oils are particularly attractive because, unlike fossil fuels, these fuels are renewable. They come from plants that can be grown in a reasonable amount of time.
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Rene Descartes (1596-1650) was a French scientist and mathematician who used this same experiment show people about buoyancy. By squeezing the bottle, the test tube (diver) sinks and when released, the test tube surfaces. You can add hooks, rocks, and more to your set up to make this into a buoyancy game!
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Yeast is a simple living organism that can break down sugars into ethyl alcohol (ethanol) and carbon dioxide. The process by which yeast breaks down sugars into ethyl alcohol and carbon dioxide is called fermentation.


The tiny gas bubbles rising in the liquid mixture in the bottle are carbon dioxide gas bubbles that are made during the fermentation. The balloon on the bottle expands and becomes inflated because it traps the carbon dioxide gas being produced.


The ethyl alcohol that is made during fermentation stays in the liquid mixture. When fermentation is finished, the liquid mixture usually contains about 13 percent ethyl alcohol. The rest of the liquid is mostly water.


The ethyl alcohol can be concentrated by a process called distillation. During distillation, the liquid fermentation mixture is heated to change the ethyl alcohol and some of the water into a vapor. The vapor is then cooled to change it back into a liquid. This distilled liquid contains 95 percent ethyl alcohol and 5 percent water. The remaining water can be removed by special distillation methods to give pure ethyl alcohol.


In some areas of the United States, ethyl alcohol is blended with gasoline to make a motor fuel known as gasohol. About 8 percent of the gasoline sold in the United States is gasohol.


Gasohol burns more cleanly than pure gasoline. This results in fewer pollutants being released into the air. The use of gasohol as a motor fuel is particularly important in cities that have a lot of smog.


Corn syrup is a mixture of simple and complex sugars and water. It is made by breaking down the starch in corn into sugars. The process is called digestion. In this experiment you changed the sugars in corn syrup using yeast. Much of the ethyl alcohol used to prepare gasohol is made by fermenting corn and corn sugar.


Over one billion gallons of ethyl alcohol are made each year by fermentation of sugars from grains such as corn. Ethyl alcohol is a renewable energy source when it is made by fermenting grains such as corn. This is because the grains, such as corn, are easily grown.


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When birds and animals drink from lakes, rivers, and ponds, how pure it is? Are they really getting the water they need, or are they getting something else with the water?


This is a great experiment to see how water moves through natural systems. We’ll explore how water and the atmosphere are both polluted and purified, and we’ll investigate how plants and soil help with both of these. We’ll be taking advantage of capillary action by using a wick to move the water from the lower aquarium chamber into the upper soil chamber, where it will both evaporate and transpire (evaporate from the leaves of plants) and rise until it hits a cold front and condenses into rain, which falls into your collection bucket for further analysis.


Sound complicated? It really isn’t, and the best part is that it not only uses parts from your recycling bin but also takes ten minutes to make.


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How does salt affect plant growth, like when we use salt to de-ice snowy winter roads? How does adding fertilizer to the soil help or hurt the plants? What type of soil best purifies the water? All these questions and more can be answered by building a terrarium-aquarium system to discover how these systems are connected together.


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This experiment not only explains how your body uses oxygen, but it is also an experiment in air pressure circles – bonus!  You will be putting a dime in a tart pan that has a bit of water in it. Then you will put a lit candle next to the dime and put a glass over the candle with the glass’s edge on the dime. Once all of the air inside the glass is used up by the candle, the dime will be easy to pick up without even getting your fingers wet! Ready to give it a try?


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Some insects are just too small! Even if we try to carefully pick them up with forceps, they either escape or are crushed. What to do?


Answer: Make an insect aspirator! An insect aspirator is a simple tool scientists use to collect bugs and insects that are too small to be picked up manually. Basically it’s a mini bug vacuum!


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Unsurprisingly, often the most interesting critters found in soil are the hardest to find! They’re small, fast, and used to avoiding things that search for them. So, how do we find and study these tiny insects? With a Berlese Funnel (Also called the Tullgren funnel)!


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As you walk around your neighborhood, you probably see many other people, as well as some birds flying around, maybe some fish swimming down a local stream, and perhaps even a lizard darting behind a bush or a frog sitting contently on top of a pond. Most likely, you know that all of these living things are animals, but they are even more closely related than that.


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The way animals and plants behave is so complicated because it not only depends on climate, water availability, competition for resources, nutrients available, and disease presence but also having the patience and ability to study them close-up.


We’re going to build an eco-system where you’ll farm prey stock for the predators so you’ll be able to view their behavior. You’ll also get a chance to watch both of them feed, hatch, molt, and more! You’ll observe closely the two different organisms and learn all about the way they live, eat, and are eaten.


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What grows in the corner of your windowsill? In the cracks in the sidewalk? Under the front steps? In the gutter at the bottom of the driveway? Specifically, how  doe these animals build their homes and how much space do they need? What do they eat? Where do fish get their food? How do ants find their next meal?


These are hard questions to answer if you don’t have a chance to observe these animals up-close. By building an eco-system, you’ll get to observe and investigate the habits and behaviors of your favorite animals. This column will have an aquarium section, a decomposition chamber with fruit flies or worms, and a predator chamber, with water that flows through all sections. This is a great way to see how the water cycle, insects, plants, soil, and marine animals all work together and interact.


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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!


Discover the world of clean, renewable energy that scientists are developing today! Explore how they are harnessing the energy of tides and waves, lean how cars can run on just sunlight and water, tour a hydroelectric power plant, visit the largest wind farms on the planet, and more! You’ll learn how streets are being designed to generate electricity, how teenagers are making jet fuel from pond scum in their garage, and how 70 million tons of salt can provide free, clean energy 24 hours a day forever! During class, you’ll learn how to bake solar cookies, magni-fry marshmallows and do the experiment with light Einstein won a Nobel prize for that is the basis of all photovoltaic energy today.


Materials:


  • One cup each: hot (not boiling), cold, and room temperature water
  • Cardboard box, shoebox size or larger.
  • Aluminum foil
  • Plastic wrap (like Saran wrap or Cling wrap)
  • Hot glue, razor, scissors, tape
  • Wooden skewers (BBQ-style)
  • Black construction paper
  • Cookie dough (your favorite kind!)
  • Chocolate, large marshmallows, & graham crackers if you want to make s’mores! If not, try just the large marshmallow.
  • Large page magnifier (also called a Fresnel lens, found at drug stores or places that also sell reading glasses, or at Amazon.com)
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Here we’re going to discuss the differences between three types of worms; flatworms, roundworms, and segmented worms. The word “worm” is not, in fact, a scientific name. It’s an informal way of classifying animals with long bodies and no appendages (no including snakes). They are bilaterally symmetrical (the right and left sides mirror each other). Worms live in salt and fresh water, on land, and inside other organisms as parasites.


The differences between the three types of worms we will discuss depend on the possession of a body cavity and segments. Flatworms have neither a body cavity nor segments. Roundworms only have a body cavity, and segmented worms have both a body cavity and segments.


Flatworms (Phylum Platyhelminthes) have incomplete digestive systems. That means that their digestive system has only one opening. The gas exchange occurs on the surface of their bodies. There are no blood vessels or nervous systems in flatworms. Some are non-parasitic, like the Sea flat worm, and some are parasitic, like the tapeworm.



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Insects are not only the most diverse subgroup of arthropods, but with over a million discovered species it is the most diverse group of animals on earth. Although they can’t all be as beautiful as a butterfly, they all play important roles in their ecosystems—just think of where we would be without bees!


The segmented exoskeletons of insects have a hard, inner layer called the cuticle, and a water-resistant outside layer called the exocuticle. Insects are divided into two major groups: winged insects and wingless insects. Air is taken in through structures called spirials, and delivered directly to the body.



Most insects reproduce sexually and are oviparous (hatch from eggs after the eggs are laid), although some insects reproduce asexually.


You can grow your own butterflies using a premade kit from Home Training Tools!


A biological net is one of the essential tools of a field biology researcher — you! A bio-net allows you to safely and gently gather samples. Whether you’re studying butterflies or tadpoles a bio-net is the tool to have! Important safety note: Do both of these with parental supervision. Many of the steps are tricky and involve sharp objects.


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When you hear “roach” you might not immediately think of something that would make a good pet, but not all roaches are like the cockroaches you might have seen in your house!


Species such as the Orange Spotted Roach (Blaptica dubia) make excellent insect pets: they don’t cost much, they have an interesting life cycle and habits, and they do not require much effort to care for. Their average lifespan is about 18 months and you’ll be able to learn more about their fascinating life cycle (from egg to adult) if you allow them to breed!


A pet roach isn’t a pest?


It may seem like all roaches are pests, but of 4,000 species, only 4 or 5 live in homes and are considered pests (such as the American cockroach). Most roaches live in tropical environments far from domesticated areas. They are very different from the kind of household pest you might think of when you hear “roach.”


You might think roaches would make pretty boring pets, but they are surprisingly fast and fun to watch. You can learn a lot about insect anatomy and what makes roaches unique by taking care of them. The species that make good pets do not smell, are not noisy, cannot fly, and generally are very easy to clean up after. They typically are most active at night, because they prefer a dark environment like they have on the floor of the rainforest. They love to hide during the day, but will come out to eat.



Can I touch them?  They are meant to be pets, and are perfectly safe to handle. A good environment for roaches is a small aquarium or plastic cage with cardboard egg cartons for them to hang out in. You might try picking up one of the egg cartons where a roach is hiding, then either hold the carton so the roach can crawl around on it or let the roach crawl in to your hands. Hold out your hand, keeping your fingers together and flat. Let the roach crawl on you, then slowly lift out your hand and cup it slightly. Remember to wash your hands afterwards, using warm water and soap. Although these insects don’t cause diseases in humans, they may be carrying harmful bacteria, so it is important to wash your hands so that you don’t get sick.


How long do they live? It varies, but species like Orange Spotted Roaches have a lifespan of 18-24 months. The female gives live birth, usually to 20-30 babies at a time. The babies reach maturity in 3-4 months after they are born. While they are growing into adults, they will molt – shedding their outer hard shell, or exoskeleton, and then growing a bigger one.


Will my roaches breed? If you get one male and one female, there is a good chance that they will breed under the right circumstances. If you do not want baby roaches, keep the temperature of the habitat around 70 degrees, or normal room temperature. Adult Orange Spotted Roaches will be fine at this temperature, but they will not mate because their young need higher temperatures to survive. If you would like to see the complete life cycle, you will need to ensure that their habitat has enough heat and humidity.


Feeding Time: What does a pet roach eat? They are omnivores – they eat plants and meat. So a good basic diet contains protein from plants and animals and fiber from grains. You can buy special roach food for them and then to supplement their diet give them fresh fruits and vegetables once a week. Try putting a slice of apple, banana, orange, carrot, potato, or zucchini, or a few spinach leaves in a shallow plastic dish and put it in their habitat. This will provide vitamins and minerals for your pets. Be sure to take the uneaten produce out of the habitat within 48 hours to prevent mold from growing, or attracting ants or fruit flies. A great roach diet would be dry food every day and a fresh food supplement once a week.


Be sure to keep their water dish full. Roaches can live a long time without food, but usually only survive three days without water. The water dish also helps make their habitat more moist and humid. For easiest care, use water absorbent crystals that hold water. You can keep an airtight container of prepared water crystals in a cool place, and add another crystal to the water dish whenever needed (usually every 2-3 days).


If the habitat is hot and humid, the roaches will be more active, which means they will also eat and drink more.


Cleaning Time: You should periodically clean out your pet roach’s habitat to make sure there is no mold growing. Cleaning out the habitat takes only a few minutes and will prevent any bad odors coming from your insects. When is the right time to clean the habitat? When you see small dark roach droppings starting to collect on the bottom, you should clean the habitat out. Usually about once a month is a good time. The minimum should be once every other month.


To clean out the habitat, first remove the roaches. Place them in a container that has smooth sides to prevent them from climbing out. Pick up the roaches one at a time and transfer them to the carton or other container. If a roach is hiding in an egg carton, carefully lift out the carton, then let the roach crawl off into the container or onto your hand. Wash your hands with soap and warm water after touching the roaches.


Take the food and water dishes out, as well as the egg cartons, and place them on paper towels. Rinse the container out and then wash it with a solution of 10 parts warm water to 1 part bleach. Rinse the container again and dry it thoroughly. Place the food and water dishes back in the container. If the cardboard egg cartons seem clean, put them back into the container. Don’t use foam egg cartons. You can also use cardboard tubes in different sizes (mailing tubes, toilet paper tubes, or wrapping paper tubes cut down to shorter lengths) so the roaches can crawl in them. When you’re finished cleaning, throw the used egg cartons away as well as the paper towels. Transfer your roaches back to their habitat, using a flat hand so they can crawl off.


Building a Roach Ranch: If you decide to get a pet roach, you can create a habitat to be as simple or creative as you like. If you wish to make a more natural-looking habitat for your pet roaches to enjoy, you can buy peat moss or coconut husk mulch from a pet store (in the Reptile section). Put in a layer of moss or mulch (about one inch), then add pieces of bark for the roaches to climb on and hide under. This type of Roach Ranch will be similar to the Orange Spotted Roaches’ natural environment in the rainforests of South America.


You can make a Roach Ranch out of cardboard, which can easily be thrown away when it gets dirty. Make a multi-level mansion for your roaches by cutting 3-4 identical shapes (square, rectangle, L-shape) from cardboard. Put separators in between each level – use stacked cardboard strips that are one inch wide and several inches long. Each level should be separated about ½” or three strips of cardboard stacked together. Use Elmer’s glue to attach the separators and flat levels, and let it dry completely (may take up to 24 hours) before putting it in your roach habitat. Add cardboard tubes or crumpled newspaper to complete your Roach Ranch. Remember that it will be easier to clean if roach droppings can fall freely to the ground. When you clean your habitat, check to see if your Roach Ranch is staying clean. Throw away any parts that have been well-used and add new cardboard material for the roaches to climb.


One place where bacteria can be found is on your teeth. This is why it’s so important to brush well. Don’t believe me? Then this experiment is for you. You’ll need to gather your materials and make sure you have a toothbrush and microscope nearby.


This is important because prokaryotes are incredibly common and have a huge impact on our lives.  You may already know some of the ways bacteria can be harmful to you, and this is certainly important information.  Scientists have used knowledge of prokaryotes to create medications, vaccines, and healthy living habits that have led to a healthier life for billions of people.


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If you’re thinking sunlight, you’re right. Natural light is best for plants for any part of the plant’s life cycle. But what can you offer indoor plants?


In Unit 9 we learned how light contains different colors (wavelengths), and it’s important to understand which wavelengths your indoor plant prefers.


Plants make their food through photosynthesis: the chlorophyll transforms carbon dioxide into food. Three things influence the growth of the plant: the intensity of the light, the time the plant is exposed to light, and the color of the light.


When plants grow in sunlight, they get full intensity and the full spectrum of all wavelengths. However, plants only really use the red and blue wavelengths. Blue light helps the leaves and stems grow (which means more area for photosynthesis) and seedlings start, so fluorescent lights are a good choice, since they are high in blue wavelengths.


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If you have ever seen mold growing on an old loaf of bread or eaten a mushroom, you have encountered a fungus. Fungi (that’s the plural of fungus) are a group of organisms, or living things, that are all around us. Mold on bread and mushrooms on pizza are both examples of fungi.


Fungi have an important job. They help break down other material, so that living things are able to grow in soil. This helps make nutritious foods for other organisms. Fungi are needed for life!


Do you think mushrooms are plants? Scientists used to think that all fungi were plants. Now they know that there are some very important different between these two groups of organisms. One of the most important differences is that plants are autotrophic. This means that they can make their own food, just by using the sunlight. Fungi can’t do this. They have to “eat” other living things in order to get the energy they need. This is called being heterotrophic.


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Living things are all around us.  Sometimes the living things we notice the most are animals, whether its birds chirping in the trees, our pet dogs, or even our fellow human beings.  However, most living things are not animals - they include bacteria, archae, fungi, protists, and plants.  These organisms are extremely important to learn about.  They make life possible for animals, including human beings, by keeping soil ready for growth, and providing oxygen for our survival.  No life would be possible without these remarkable organisms.

The prokaryotes, bacteria and archaea represent an amazingly diverse group of organisms only visible when one looks under a microscope. These single-celled organisms obtain energy and reproduce in a variety of ways.

Though some bacteria are harmful, causing disease, many are very helpful, providing the nitrogen we need to live and aiding in digestion. Archaea have been found in some of the most extreme environments on the planets, including environments that are remarkably hot or salty.

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Ah-chooo! Influenza (the “flu”) is when you get chills, fever, sore throat, muscle pains, headaches, coughing, and feel like all you want to do is lie in bed. The flu is often confused with the common cold, but it’s a totally different (and more severe) virus.


The flu is passed from person to person (or animals or birds) by coughing or sneezing. With plants, it’s transmitted through the sap via insects. In the case of birds and animals, the flu is usually transmitted by touching their droppings, which is why hand-washing is so important! In addition to soap, the flu virus can be inactivated by sunlight, disinfectants and detergents.


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Birds, people, plants, and microscopic organisms need to know where they are as well as where they want to be. Birds migrate each year and know which way is south, and plants detect the sun so they can angle their leaves properly. People consult a map or GPS to figure out where they are.


Magnetotactic bacteria orients itself along magnetic field lines, whether from a nearby magnet or the Earth’s magnetic field. It’s like having a built-in internal compass.


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All living things need a way to get energy. Bacteria get their food and energy in many ways. Some bacteria can make food on their own, while others need other organisms.


Some bacteria help other living things as they get energy, others hurt them while they get energy, and still others have no affect on living things at all.
Some living things, or organisms, are able to make their own food in a process called photosynthesis.


In this process, the organism turns energy from the sun into energy that can be used for energy. Organisms that get their energy from photosynthesis are called autotrophs. Some bacteria get their energy this way.


Some bacteria, called chemotrophs, get their energy by breaking down chemical compounds in the environment, including ammonia. Breaking down ammonia is important because ammonia contains the element nitrogen.


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Bacteria have a bad reputation. Walk down the cleaning aisle of any store and you’ll see rows and rows of products promising to kill them. There are definitely some bacteria that cause problems for people, and we’ll talk about them soon, but we are going to start off positive, and talk about the many ways bacteria can be helpful.


First, decomposers help control waste. Without these bacteria, the amount of waste in soil would quickly make the soil a place where nothing could grow. Bacteria are even used in sewage treatment plants to treat our waste. Decomposers also help provide organisms with nitrogen, as was discussed earlier.


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If your kitchen is like most kitchens, you probably have cabinets for cups and pots and pans, along with drawers for silverware and cooking utensils.  You might also have a drawer you call the “junk drawer.”  The things in this drawer aren’t actually “junk.”  If they were, you’d throw them away.  Instead, things usually get put here because they just don’t fit anywhere else.


You might be surprised to learn that the system for classifying organisms has its own “junk drawer.”  It’s called the protist kingdom.  Its members, like the contents of your kitchen junk drawer, are important, but don’t fit nicely in one of the other kingdoms.


Broadly, protists can be classified as animal-like, plant-like, or fungus-like.  It is important to remember that being “animal-like” does not make a protist an animal.  Such and organism, like plant-like or fungus-like protists, are members of an entirely different group of living things.


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Six-foot zucchini? Ten-foot carrots? Are giant veggies just a photography trick, or are they real?


The happy news is that yes, they’re real! Expert horticulturists have accumulated a great wealth of knowledge about different climates and dirt conditions. They must know about the different chemical, physical and biological properties of gardens and do multiples of experiments dozens of plants. We found an incredible horticulturist, John Evans, who has accumulated over 180 first places in both quality and giant vegetable categories, with 18 State and 7 World Records.


According to John Evans: “If you could, imagine what it would be like to dig up a carrot from your garden and not knowing how big it is until the last minute, and then finding out that it’s 19 lbs. Now that’s exciting!”


John has spent many years developing fertilizers, bio-catalysts, and growing techniques to grow 76-lb cabbages (photo shown left), 20-lb carrots, 29-lb kale, 60-lb zucchini,  43-lb beets, 35-lb broccoli and cauliflowers, and 70-lb swiss chard that was over 9 feet tall and took three people to carry it to the trailer!


Here’s a video on growing giant flowers by a passionate community gardening club:
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When you hear the word “bacteria” what do you think of? If you’re like most people, you probably think of things that can make you sick. Although some bacteria do make us sick, this is not true for all of them. In fact, as we’ll see a little later, some bacteria are very helpful.


Did you know that bacteria can have a virus? It’s true! But first, you might be wondering: what’s the difference between viruses and bacteria?


Bacteria grows and reproduces on its own, while viruses cannot exist or reproduce without being in a living cell of a plant, animal, or even bacteria. Size-wise, bacteria are enormous.


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It drives me crazy it when my store-bought tomatoes go straight from unripe to mush. After talking with local farmers in my area, I discovered a few things that might help you enjoy this fruit without sacrificing taste and time.


Grocery store owners know that their products are very perishable. If the tomatoes arrive ripe, they might start to rot before they can get on the shelf for the customer. Ripe tomatoes are near impossible to transport, which means that farmers often pick unripe (green and therefore very firm) tomatoes to put on the truck. Grocery stores prefer hard, unripe tomatoes so their customers can get them home safely.


The problem is, how do you enjoy a tomato if it’s not ready?


Scientists and food experts ripen tomatoes quickly with ethylene while they are in storage. As the gas surrounds the green tomato, it chemical reacts to speed up the ripening process, causing the tomato to soften and change color to red or orange.


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This type of slime Physarum Polycephalum is called the “many-headed slime”. This slime likes shady, cool, moist areas like you’d find in decaying logs and branches. Slime (or slime mold) is a word used to define protists that use spores to reproduce. (Note: Slime used to be classified as fungi.)


Real slime lives on microorganisms that inhabit dirt, grass, dead leaves, rotting logs, tropical fruits, air conditioners, gutters, classrooms and laboratories. Slime can grow to an area of several square meters.


Slime shows curious behaviors. It can follow a maze, reconnect itself when chopped in half, and predict whether an environment is good to live in or not. Scientists have battled with the ideas that at first glance, slime appears to be simply a “bag of amoebae”, but upon further study, seem to behave as if they have simple brains, like insects.


Slime can be either a plasmodial slime, a bag of cytoplasm containing thousands of individual nuclei, or a cellular slime which usually stays as individual unicellular protists until a chemical signal is released, causing the cells to gather and acts as one organism.
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Fungi and protists, including mold, moss, yeast, and mushrooms, are found all around us. One common group of fungi is mold. Mold, like all fungi, are heterotrophs, which means they rely on other living things for their energy. This is different than an autotroph like a plant, which gets its energy from the sun.


Mold commonly grows on bread, getting food from this source. What do you think makes mold grow? Being in a dark place? Being exposed to moisture? Something else? The scientific method is a series of steps some scientists use to answer question and solve problems. To conduct an experiment based on the scientific method, you must have a control sample, which has nothing done to it, and several experimental samples, which have changes made to them. You can then observe results in the experimental sample to see how your changes to them affect results.


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Art and science meet in a plant press. Whether you want to include the interesting flora you find in your scientific journal, or make a beautiful handmade greeting card, a plant press is invaluable. They are very cheap and easy to make, too!


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Flowering plants can be divided into monocotyledons and dicotyledons (monocots and dicots). The name is based on how many leaves sprout from the seed, but there are other ways to tell them apart. For monocots, these will be in multiples of three (wheat is an example of a monocot). If you count the number of petals on the flower, it would have either three, six, nine, or a multiple of three. For dicots, the parts will be in multiples of four or five, so a dicot flower might have four petals, five petals, eight, ten, etc.

Let's start easy...grab a bunch of leaves and lets try to identify them. Here's what you need to know:

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Mass and energy are conserved. This means you can’t create or destroy them, but you can change their location or form.


Most people don’t understand that the E energy term means all the energy transformations, not just the nuclear energy.


The energy could be burning gasoline, fusion reactions (like in the sun), metabolizing your lunch, elastic energy in a stretched rubber band… every kind of energy stored in the mass is what E stands for.


For example, if I were to stretch a rubber band and somehow weigh it in the stretched position, I would find it weighed slightly more than in the unstretched position.


Why? How can this be? I didn’t add any more particles to the system – I simply stretched the rubber band. I added energy to the system, which was stored in the electromagnetic forces inside the rubber band, which add to the mass of the object (albeit very slightly). Read more about this in Unit 7: Lesson 3.


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Plants need light, water, and soil to grow. If you provide those things, you can make your own greenhouse where you can easily observe plants growing. Here’s a simple experiment on how to use the stuff from your recycling bin to make your own garden greenhouse.


We’ll first look at how to make a standard, ordinary greenhouse. Once your plants start to grow, use the second part of this experiment to track your plant growth. Once you’ve got the hang of how to make a bottle garden, then you can try growing a carnivorous greenhouse.
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Broccoli, like all plants, has chlorophyll, making it green. You can really “see” the chlorophyll when you boil broccoli. This is such a simple experiment that you can do this as you prepare dinner tonight with your kids. Make sure you have an extra head of broccoli for this experiment, unless you really like to eat overcooked broccoli.

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If you have a backyard garden, be sure to give it plenty of sunshine, water, and garbage.


Wait… garbage?  Yes, you read that right.


Garbage like rotting food and coffee grounds, made into compost, can be highly beneficial to garden plants.  Why? It all has to do with nitrogen.


Plants need nitrogen in order to survive.  There is plenty of nitrogen in the atmosphere; the problem is that plants can’t use it in the form found in the atmosphere.  For this, bacteria are needed.  Bacteria “fix” nitrogen, meaning that they change it into a usable form.


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Keep your compost heap moist, but not soggy and turn it with a pitchfork or spade to add air into the mix.  Once your compost bin is going strong, you can add it to your garden for improved plant growth!


If you’ve ever eaten fruits or vegetables (and let’s hope you have), you have benefited from plants as food.  Of course, the plants we eat have been highly modified by growers to produce larger and sweeter fruit, or heartier vegetables.


There are three basic ways to create plants with new, more desirable traits:


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A ferrofluid becomes strongly magnetized when placed in a magnetic field. This liquid is made up of very tiny (10 nanometers or less) particles coated with anti-clumping surfactants and then mixed with water (or solvents). These particles don’t “settle out” but rather remain suspended in the fluid.


The particles themselves are made up of either magnetite, hematite or iron-type substance.


Ferrofluids don’t stay magnetized when you remove the magnetic field, which makes them “super-paramagnets” rather than ferromagnets. Ferrofluids also lose their magnetic properties at and above  their Curie temperature points.


Ferrofluids are what scientists call “colloidal suspensions”, which means that the substance has properties of both solid metal and liquid water (or oil), and it can change phase easily between the two. (We as show you this in the video below.) Because ferrofluids can change phases when a magnetic field is applied, you’ll find ferrofluids used as seals, lubricants, and many other engineering-related uses.


Here’s a video on toner cartridges and how to make your own homemade ferrofluid. It’s a bit longer than our usual video, but we thought you’d enjoy the extra content.


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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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Did you know that supercooled liquids need to heat up in order to freeze into a solid? It’s totally backwards, I know…but it’s true! Here’s the deal:


A supercooled liquid is a liquid that you slowly and carefully bring down the temperature below the normal freezing point and still have it be a liquid. We did this in our Instant Ice experiment.


Since the temperature is now below the freezing point, if you disturb the solution, it will need to heat up in order to go back up to the freezing point in order to turn into a solid.


When this happens, the solution gives off heat as it freezes. So instead of cold ice, you have hot ice. Weird, isn’t it?


Sodium acetate is a colorless salt used making rubber, dying clothing, and neutralizing sulfuric acid (the acid found in car batteries) spills. It’s also commonly available in heating packs, since the liquid-solid process is completely reversible – you can melt the solid back into a liquid and do this experiment over and over again!


The crystals melt at 136oF (58oC), so you can pop this in a saucepan of boiling water (wrap it in a towel first so you don’t melt the bag) for about 10 minutes to liquify the crystals.


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Did you know that most people can’t crack an egg with only one hand without whacking it on something? The shell of an egg is quite strong! Try this over a sink and see if you can figure out the secret to cracking an egg in the palm of your hand…(Hint: the answer is below the video – check it out after you’ve tried it first!)


How can you tell if an egg is cooked or raw? Simply spin it on the counter and you’ll get a quick physics lesson in inertia…although you might not know it. A raw egg is all sloshy inside, and will spin slow and wobbly. A cooked egg is all one solid chunk, so it spins quickly. Remember the Chicken and the Clam experiment?


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If you soak chicken bones in acetic acid (distilled vinegar), you’ll get rubbery bones that are soft and pliable as the vinegar reacts with the calcium in the bones. This happens with older folks when they lose more calcium than they can replace in their bones, and the bones become brittle and easier to break. Scientists have discovered calcium is replaced more quickly in bodies that exercise and eating calcium rich foods, like green vegetables.


This is actually two experiments in one – here’s what you need to do:


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Did you know that you can use a laser to see tiny paramecia in pond water? We’re going to build a simple laser microscope that will shine through a single drop of water and project shadows on a wall or ceiling for us to study.


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Have you ever tried washing dishes without soap? It doesn’t work well, especially if there’s a lot of grease, fat, or oil on the dish!


The oils and fats are slippery and repel water, which makes them a great choice for lubration of bearing and wheels, but lousy for cleaning up after dinner.


So what’s inside soap that makes it clean off the dish? The soap molecule looks a lot like a snake, with a head and a tail. The long tail loves oil (hydrophobic) and the head loves water (hydrophilic). The hydrophilic end dissolves in water and the hydrophobic end wraps itself around fat and oil in the dirty water, cleaning it off your dishes.


Let’s do an experiment that will really make you appreciate soap and fat:


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Being able to predict tomorrow's weather is one of the most challenging and frequently requested bits of information to provide. Do you need a coat tomorrow? Will soccer practice be canceled? Will the crops freeze tonight?

Scientists use different instruments to record the current weather conditions, like temperature, barometric pressure, wind speed, humidity, etc. The real work comes in when they spend time looking over their data over days, months, even years and search for patterns.

But where does the weather station get its weather from?

One of the greatest leaps in meteorology was using numbers to predict the flow of the atmosphere. The math equations needed for these (using fluid dynamics and thermodynamics) are enough to make even a graduate student quiver with fear. Even today's most powerful computers cannot solve these complex equations! The best they can do is make a guess at the solution and then adjust it until it fits well enough in a given range. How do the computers know what to guess?

Several weather stations around the world work together to report the current weather every hour. These stations can be land-based, mounted on buoys in the ocean, or launched on radiosondes and report back to a home station as they rise through the different layers of the atmosphere. Pilots will also give weather reports en route to their destination, which get recorded and added to the database of weather knowledge.

We're going to build our own homemade weather station and start keeping track of weather right in your own home town. By keeping a written record (even if it's just pen marks on the wall), you'll be able to see how the weather changes and even predict what it will do, once you get the hang of the pattern in your local area. For example, if you live in Florida, what happens to the pressure before the daily afternoon thunderstorm? Or if you live in the deserts of Arizona, what does a sudden increase in humidity tell you?
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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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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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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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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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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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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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If the cell has a nucleus, the DNA is located in the nucleus.  If not, it is found in the cytoplasm.  DNA is the genetic material that has all the information about a cell.


DNA is a long molecule found in the formed by of two strands of genes. DNA carries two copies—two “alleles”—of each gene. Those alleles can either be similar to each other (homozygous), or dissimilar (heterozygous).


We’re going to learn how to extract DNA from any fruit or vegetable you have lying around the fridge. Are you ready?


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Why do families share similar features like eye and hair color? Why aren’t they exact clones of each other? These questions and many more will be answered as well look into the fascinating world of genetics!


Genetics asks which features are passed on from generation to generation in living things. It also tries to explain how those features are passed on (or not passed on). Which features are stay and leave depend on the genes of the organism and the environment the organism lives in. Genes are the “inheritance factors “described in Mendel’s laws. The genes are passed on from generation to generation and instruct the cell how to make proteins. A genotype refers to the genetic make-up of a trait, while phenotype refers to the physical manifestation of the trait.


We’re going to create a family using genetics!


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A pedigree analysis chart, usually used for families, allow us to visualize the inheritance of genotypes and phenotypes (traits). In this chart, the P, F1, and F2 generation are represented by the numerals I, II, and III respectively. Notice that those carrying the trait are colored red, and those not carrying the trait (the normal-looking ones) are in blue. The normal, non-trait carrying organisms on the chart are called the wild-type.


The term wild-type is used in genetics often to refer to organisms not carrying the trait being studied. For example, if we were studying a gene that turns house-flies orange, we would call the normal-looking ones the wild-type.


Let’s make a pedigree for your family. Here’s what you need:


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Cells make up every living thing. Take a look at all the living things you can see just in your house. You can start off with you and your family. If you have any pets, be sure to include them. Don’t forget about houseplants as well – they’re alive. Now take a walk outside. You’ll likely see many more plants, as well as animals like birds and insects. Now imagine if all those living things were gone. That’s how it would be if there were no cells, because cells are what all those living things are made of.


Animals, plants and other living things look different, and contain many different kinds of cells, but when you get down to it, all of us are just a bunch of cells – and that makes cells pretty much the most important thing when it comes to life!


Here’s a video on the difference between animal and plant cells:



Are you wondering what all the different organelles are inside the cell? Here’s a video that goes into all the cool detail (note – this video is more for advanced students):



Now pull out your science journal! As you watch this video below, write down the organelles you see and describe what you think is happening.



What’s going on?


The endoplasmic reticulum, shown in red, transports proteins to the Golgi Apparatus, shown in blue. The Golgi Apparatus packages proteins and sends them where they are needed, either in the cell, or to the cell membrane for transport out of the cell.


This experiment allows you to see protozoa, tiny-single celled organisms, in your compound microscope. While I can go in my backyard and find a lot of interesting pond scum and dead insects, I realize that not everybody has a thriving ecosystem on hand, especially if you live in a city.


I am going to show you how to grow a protozoa habitat that you can keep in a window for months (or longer!) using a couple of simple ingredients.


Once you have a protist farm is up and running, you’ll be able to view a sample with your compound microscope. If you don’t know how to prepare a wet mount or a heat fix, you’ll want to review the microscope lessons here.


Protozoa are protists with animal-like behaviors. Protists live in almost any liquid water environment. Some protists are vital to the ecosystem while others are deadly.


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If you think of celery as being a bundle of thin straws, then it’s easy to see how this experiment works. In this activity, you will get water to creep up through the plant tissue (the celery stalk) and find out how to make it go faster and slower.


The part of the celery we eat is the stalk of the plant.  Plant stalks are designed to carry water to the leaves, where they are needed for the plant to survive.  The water travels up the celery as it would travel up any plant.


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Some organisms, like bacteria, consist of only one cell. Other organisms, like humans, consist of trillions of specialized cells working together. Even if organisms look very different from each other, if you look close enough you’ll see that their cells have much in common.


Most cells are so tiny that you can’t see them without the help of a microscope. The microscopes that students typically use at school are light microscopes.


Robert Hooke created a primitive light microscope in 1665 and observed cells for the very first time. Although the light microscope opened our eyes to the existence of cells, they are not useful for looking at the tiniest components of cells. Many structures in the cell are too small to see with a light microscope.
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One way substances can get into a cell is called passive transport. One special kind of passive transport is osmosis, when water crosses into the cell. This experiment allows you to see the process of osmosis in action. Are you ready?


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Photosynthesis is a process where light energy is changed into chemical energy.  As we said in the last section, this process happens in the chloroplast of plant cells.  Photosynthesis is one of the most important things that happen in cells.


In fact, photosynthesis is considered one of the most important processes for all life on Earth.  It makes sense that photosynthesis is really important to plants, since it gives them energy, but why is it so important to animals?  Let’s learn a little more about photosynthesis and see if we can answer that question.


There are many steps to photosynthesis, but if we wanted to sum it up in one equation, it would be carbon dioxide (CO2) + water (H2O) makes glucose (C6H12O6) and oxygen (O2).  These words can be written like this:


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In eukaryotes there is a nucleus, so a more complex process called mitosis is needed with cell division. Mitosis is divided into four parts, or phases:


Phase 1 – Prophase: In this phase the nuclear membrane begins to break down and the DNA forms structures called chromosomes.


Phase 2 – Metaphase: In this phase the chromosomes line up along the center of the parent cell


Phase 3 – Anaphase: In this phase, the chromosomes break apart, with a complete set of DNA going to each side of the cell


Phase 4 – Telophase: In this phase, a new nuclear membrane forms around each of the sets of DNA


The four stages of mitosis (the cell at the top has not started mitosis) lead to two daughter cells.


A little after telophase, the cytoplasm splits and a new cell membrane forms.  Once again, two daughter cells have formed.  Take a look at this animation for a good overview of mitosis and see if you can identify all the phases.


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