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P lants use the Sun’s energy to make food through pho-tosynthesis. This process helps to build bio-mass. Biomass is the plant material and

animal waste that are used as a source of fuel or energy. Eight red, sunlit bundles of light energy dance on a plant leaf down to the green chlorophyll, turning on a chemi-cal-making system inside the plant. The plant uses water and carbon dioxide (CO2) from air as its raw materials. Two water (H2O) molecules are split into two hydrogen atoms and one oxygen atom. The hydrogen atoms are added to the carbon dioxide that is grabbed out of the air, and two oxygen atoms bond together and are set free. Thanks to the process of photosyn-thesis, you can now breathe deeply: The plant just released oxygen for you!

Plants use the carbon in the carbon dioxide to build carbohydrates, sugars, starches, cellulose fibers, and fats in seed oils for you to eat. Think about it: Sugar cane, sweet corn, potatoes, celery, cellulose crunch, sunflower seeds, and soybean oils with all of their flavors and fragrances are the materials of biomass.

Biomass can be converted to all of the following: energy, ethanol, methane, and biodiesel, as shown below.

Biomass to energy: Sit near a hot campfire, and you know that solid wood can be burned to produce heat energy. Biofuels are made from biomass. These liquid and gas biofuels can be burned for transportation, heat, or electricity. The energy stored in the food you have eaten is measured in calories and is burned by your body during exercise. Biofuel car engines and generators also burn calories to move and create electricity. Coal, oil, and gasoline are being replaced by biofuels as chemists and engineers discover ways to make and use these renewable energy materials.

Biomass to ethanol: Plant sugars, starches, and cellulose can be transformed into ethanol in large biorefineries. Biorefiner-ies take plant waste (from farms and cities), grass, and crops and convert them into ethanol.

Sugar cane, cornstarch, and other plant material can also be changed into ethanol with the help of millions of

microorganisms (yeast) that eat sugars during fermentation. The ethanol produced can be

mixed with gasoline to use in automobiles as fuel.

Biomass to methane: Plants decay naturally into biogases like carbon dioxide (CO2) and methane (CH4) through a chemi-

cal change called digestion. The methane collected is called natural gas. The gas is so

natural that cows “burp” methane from grass digestion. Biorefineries have digester tanks to convert

plant waste to methane. Farm waste like corncobs, cereal grain material, and landscaping grass, as well as household vegetable waste and farm animal waste like manure, are

placed in the digester. Manure is added to make diges-tion more efficient because it contains millions of

microorganisms that can help digest plant ma-terial. The natural gas is collected and stored

as a gas or liquid in large tanks. Garbage trucks, city buses, warehouse forklifts, and hospital electricity generators can use natural gas, one of the cleanest burning-energy fuels, to operate.

Biomass to biodiesel: Oils in plant seeds and nuts such as sunflower and pea-

nuts can be used to make biodiesel fuel. These oily liquids can be made through a chemical change into

a biodiesel called FAME (short for fatty acid methyl esters). Plant oils are mixtures of fats and fatty acids, which are trans-formed into FAME by a reaction with methanol. Biodiesel fuels

are sometimes blended in small amounts with diesel fuel that we use today. Used cooking oil from

cooking French fries and other fried foods can also be recycled to create biodiesel fuel.

Biomass to ethanol, methane, and biodiesel are just a few of the many amazing chemi-cal transformations that can occur from

plants to biofuels. Biomass energy starts with the Sun, which makes biofuel a renewable

energy source.

Biomass to EnergyBy Jeff Trent

Milli’s Safety Tips Safety First!

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IntroductionJust about everything has potential energy stored in it. The problem is releasing that energy to be able to do some work. A tiny peanut contains stored chemical energy. When we eat them, the stored energy is converted by our bod-ies so we can do work. We can also use the energy in a peanut to heat a container of water.

SAFETY Be sure to follow Milli’s Safety Tips and do this activity with an adult!

Materials• Small bag/can of unsalted, shelled peanuts • Cork • Needle • Large 40-ounce metal juice or coffee can • Small metal can (like a soup can)

with paper label removed • Can opener • Hammer • Large nail • Metal barbecue skewer

(like the kind for kebabs) • 1 cup of water • Thermometer • Matches or a lighter (ask an adult for help) • Paper • Pencil

Procedure1. Carefully push the eye of the needle into the smaller

end of the cork. Then gently push the pointed end of the needle into a peanut. If you push too hard, the peanut will break. If it does, use another peanut. It’s also better to have the peanut at a slight angle. See Diagram 1.

2. Remove the two ends of the large juice can with the can opener. Be careful—the top and bottom edges can be sharp!

3. Have an adult use the hammer and nail to punch holes around the bottom of the large can. These are air holes that will make the can act like a chimney and will contain the heat energy, focusing it on the smaller can.

Power from the Peanut

AlwAYS:• Work with an adult.• Read and follow all

directions for the activity.• Read all warning labels

on all materials being used.

• Wear eye protection, specifically goggles.

• Follow safety warnings or precau-tions, such as wearing gloves, or tying back long hair.

• Use all materials carefully, following the directions given.

• Be sure to clean up and dispose of materials properly when you are finished with an activity.

• Wash your hands well after every activity.

NEvEr eat or drink while conducting an experiment, and be careful to keep all of the materials used away from your mouth, your nose, and your eyes!

NEvEr experiment on your own!

PEANUTS

For more detailed information on safety, go to www.acs.org/earthday and click on “Safety Guidelines.”

4. Remove the top end of the small can (if it is not al-ready removed). Have an adult use the hammer and nail to punch two holes near the top of the small can exactly opposite each other.

5. Slide the barbecue skewer through the holes of the small can.

6. Pour a ½ cup of water into the small can and let it sit for an hour. This will allow the water to be heated or cooled to room temperature.

7. Put the thermometer into the water and record the temperature on your paper.

8. Place the cork and peanut on a nonflammable sur-face. Have an adult light the peanut with a match or lighter. Sometimes the peanut can be difficult to light, so a lighter may be easier to use.

9. As soon as the peanut has caught fire, immediately place the large can around the nut. Balance the skewer holding the small can on the top of the large can. See Diagram 2.

10. Allow the nut to burn for several minutes until it goes out.

11. Stir the water with a spoon. Take the temperature of the water and record it.

For more detailed information on safety, go to www.acs.org/earthday and click on “Safety Guidelines.” Diagram 1

Try this!Try a couple of other experiments using different kinds of peanuts or other kinds of nuts. Make sure the sizes of the different kinds of nuts are about that of a peanut.

Try:• raw, dry roasted, vacuum-packed, or freeze-dried pea-

nuts; or• cashew nuts, Brazil nuts, pecans, walnuts, or other

kinds of nuts. (Do they contain more energy than the peanut? Why or why not?)

You might want to try more than one peanut. You’ll need extra needles. Use four or five peanuts to heat the water. Is the temperature four or five times higher?

Where’s the chemistry?The chemical energy stored in the peanut was released and converted into heat energy. The heat energy raised the tem-perature of the water in the small can.

Diagram 2

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W ind has always fascinated people. Early hu-mans did not know where wind came from or what caused it, but they could see its

effects on leaves moving in trees, pinwheels, windmills, kites, and so on. They even created stories to explain wind.

Wind is caused by the Sun heating the air surround-ing the Earth. Air that is warmed becomes less dense and rises, much like a balloon filled with helium rises in the air. Air that has been cooled is denser and sinks to replace the warm air. The movement of warm and cool air, (along with the Earth’s rotation) causes it to move. This constant movement, whether fast or slow, is what we know as wind.

Sails on ships and boats have used the power of the wind to move. Early humans used branches with animal skins stretched across them as a sail. Sails were used for ships that traveled on the Nile River over 5,000 years ago! The sails were in the shape of a square and worked by catching wind from the rear of the ship and pushing it in the direction of the wind. Over time, triangular shaped sails were utilized, allowing ships to sail against the wind. More than one mast for sails was built to move large ships. The late 19th century saw the end of widespread use of sails. Traditional sailing ships required large crews to work the sails. Now because of electric motors, one

person can control the modern sail systems on a ship. Another early development in wind energy is the

windmill. Windmills used sail-like structures to catch the wind and use its power to make work easier. The people of China used windmills to pump water over 2,000 years ago. The people of ancient Persia used windmills to pump water and grind grain. With the coming of steam engines and other forms of energy, the extensive use of windmills, like sails, declined.

Wind energy was replaced by motors, which run on other sources of power, such as coal, oil, natural gas, and electricity in the late 1800s. The increasing price of fuel and harmful environmental effects have led scientists to find more ways to use wind energy. Today, windmills have been redesigned and improved to generate electricity. These new windmills are called wind turbines. These are being used to reduce the amount of fuel used and pollut-ants produced.

Wind energy is not stable, because of the unpredict-able nature of wind, but it can do much to increase other sources of electricity. Wind power is making a comeback, assisting powered motors and generating electricity with-out fuel or pollution. One of mankind’s oldest sources of power has now become one of the newest.

Wind PowerBy Michael Sheets

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Introduction In these two activities, you will change one form of energy into another. After doing each activity, write down the first kind of energy and then write down the energy it was changed into after the conversion.

Part 1Materials• Wire clothes hanger• Masking tape

SAFETY Be sure to follow Milli’s Safety Tips and do this activity with an adult!

Before beginning this activity, wrap the entire hook of the hanger with masking tape so that the end is completely covered.

1. Hold the bottom section of the hanger with both hands as shown.

2. Bend a section of it back and forth five times. Gently touch the bent part. What do you notice?

3. Bend it back and forth five more times, but faster than you did before. Touch the bent part again. What do you notice? Where did some of the energy go that you used to bend the hanger?

Ask yourself…What kind of energy was used in the reaction?What kind of energy was produced in the reaction?

Part 2 Materials• Aluminum foil • Lamp• Scissors • Pushpin• Thread • Tape

1. Cut a spiral from a sheet of aluminum foil. Carefully poke a small hole in the aluminum foil with a pushpin. Put a piece of thread through the hole and use a small piece of tape to hold the thread in place.

2. Hang the spiral by the thread, and hold it about 5 centimeters above a lamp. What happens? How might you change the spiral to make it spin faster? List as many ways as you can think of.

3. Try making a new spiral with one of your ideas. Did the new spiral spin differently than the original spiral?

Ask yourself…What does this remind you of?What do you think is causing the spiral to spin?

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SAFETY Be sure to follow Milli’s Safety Tips and do this activity with an adult!

Procedure1. Make sure the cardboard is folded into its box shape and

closed.

2. Place the piece of notebook paper in the center of the lid of the box and trace its outline on the lid. Put the piece of paper aside.

3. Carefully cut the two long edges and one of the short edges of the rectangle that you just traced on the lid of the box, forming a flap of cardboard.

4. Gently fold the flap back along the uncut edge to form a crease.

5. Wrap the underside (inside) face of this flap with aluminum foil. Tape it on the other side so that the foil is held firmly. Try to keep the tape from showing on the foil side of the flap. The foil will help to reflect the sunlight into the box.

6. Open the box and place a piece of black construction paper in so it fits the bottom of the box. This will help to absorb the Sun’s heat.

Try it!On a sunny day, pick a treat to warm up and carry it and the box outside to a sunny spot. If it’s cold outside, put a towel or blanket under the box so the bottom doesn’t get cold. Open the box, put the treat in the center, and close the box. Now open the flap and turn the box so the foil is facing the Sun. The shadow of the flap should go straight back from the back of the box. Move the flap up and down and note how it reflects the sunlight. Use a dowel, ruler, or stick to prop up the flap so that it bounces the sunlight into the box. Wait about 30 minutes for the box to warm up in the Sun. Then enjoy your warmed-up treat!

wArNiNg: Never stare directly at the sun or at reflected light from the sun.

Pizza Box Solar

Oven

IntroductionThe Sun is hot enough to bake food. Here’s how to make a simple solar oven that gets hot enough to warm up cookies and other treats, like s’mores. It won’t get really hot, though, so you can’t bake things in it and you won’t burn yourself when playing with it. Be sure to have an adult help you with this!

Materials One unused pizza box from a local pizza delivery store. Here’s a good excuse to ask your parents to order pizza tonight!

• Newspapers • Tape • Scissors • Black construction paper • Clear plastic wrap • Aluminum foil • A piece of notebook paper • A pencil or pen • A ruler or a wooden dowel or a stick

7. Close the box, roll up some newspaper, and fit it around the inside edges of the box. This is the insulation that helps hold in the Sun’s heat. It should be about 1 to 1½ inches thick. Use tape to hold the newspaper in place, but only tape it to the bottom of the box, not the lid.

8. Cut two pieces of plastic wrap an inch larger than the flap opening on the box top. Open the box again and tape one piece of plastic wrap to the underside of the flap opening. After taping one side, BE SURE TO PULL THE PLASTIC WRAP TIGHT, and tape down all four sides, so that the plastic is sealed against the cardboard. Then close the box and tape the other piece of plastic wrap to the top of the flap opening. Again, be sure the plastic wrap is tight, and tape down all four edges to form a seal. This creates a layer of air as insulation that helps keep the Sun’s heat in the box.

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process can be very dangerous. These dangerous atoms must be kept safely away from people and animals. The United States has about 100 safely operating nuclear power plants that create electricity and run almost con-tinuously.

Nuclear power offers many advantages. Nuclear fuel contains a lot of energy. The new fuel only needs to be added to the nuclear power plant once a year. This is dif-ferent from a coal-burning plant, which may use a train-load of coal every day. A properly running nuclear power plant releases almost no pollutants, compared to coal plants, which release pollutants like carbon dioxide, which causes the Earth to get warmer. Although the breaking up of atoms does not give off any carbon dioxide, getting the uranium from the ground and making it useful for the planet does mean that some carbon dioxide is produced.

The use of nuclear energy helps produce electricity in nuclear power plants. It is safer, creates little to no pollu-tion, and is more efficient.

By Andy Jorgensen

F or about 50 years, chemists have used a special type of energy to produce electricity, called nuclear energy. Most objects are made of stable atoms that

exist in combinations. Chemical reactions (like burning) cause variations in the arrangement of those atoms, often with changes in energy. Nuclear reactions are simpler because the variations occur inside of the atom. The fuel used to create nuclear energy is made of unstable atoms of elements like uranium that split and then release energy all at once. Some atoms split without any help. This split can be increased if they are hit by parts of other atoms, like billiard balls on a pool table.

The normal break up of atoms releases energy that can be used for other purposes, like producing electricity. In nuclear power plants, the element uranium is used as the fuel. Most uranium atoms are stable, but some break apart on their own. Nuclear reactors produce energy by both the normal and forced splitting of atoms. Electricity produced in a nuclear power plant is similar to what is produced in a power plant that burns coal. In both cases, the heat (whether from burning or the splitting of atoms) is used to boil water. The water releases steam that turns a turbine, which is the ma-chine that really produces the electricity.

The nuclear reaction must be carefully con-trolled, or too much energy can be released, which can cause damage. In addition to the danger from releasing too much energy, some of the atoms that are created during the splitting

Nuclear Energy