HYDROPOWER – ENERGY FROM WATER



Classwork (15 minutes per station):

Station 1: Hydropower (Waterwheel)

Station 2: Wind Power (Pinwheel)

Station 3: Geothermal Power (Earth’s Core)

Station 4: Solar Power (Sun)

Station 5: Biomass Power (Ethanol)

Station 6: Landfill Power (Methane Gas)

Station 7: Bringing it All Together with Google Earth

HYDROPOWER – ENERGY FROM WATER

Hydropower is the process by which the energy from flowing water is converted to an energy that can be used to generate electricity. This conversion of energy is generally done with a turbine. A turbine consists of a system of wheels and blades that can be turned by water, wind, gas, or steam.

An early water turbine is the water wheel. Water turns the blades of a wheel that is connected to an axle shaft. This axle shaft is then used to turn other gears to generate a force in another direction.

The advantage of hydropower is that it does not require any fuel source other than a steady flow of water. The disadvantage is that without a forceful and steady flow of water, the turbine will not rotate. This is why hydroelectric power plants and generators are located along rivers and near the bottom of dams.

The flow of water turns large spinning axles of the turbine, which turn coils of wire around magnets to generate electricity. The power a water turbine generates depends on the amount of water available and the distance it travels before striking turbine blades.

Approximately 20 percent of the current world electricity demands are produced from hydropower.

ACTIVITY ONE: Power Generated by a Water Turbine

Step 1: Turn the water wheel with your hand. Right now you are holding the shaft of the axle so that only the pedal wheel is free to rotate.

In a hydropower plant the wheel is fixed to the axle so that the shaft will turn with the wheel. The shaft would then turn a generator to produce electricity.

Step 2: Position the water wheel so that the flow from the faucet strikes the water wheel to turn the blades.

Step 3: Begin with a slow trickle of water. Gradually increase the flow of water from the faucet and observe the affect of changing the amount of water on the movement of the water wheel.

1) How does the amount of water from the faucet affect the speed at which the wheel turns?

Step 4: Gradually lower and raise the water wheel parallel with the water source.

2) What affect does the position and heights of the waterwheel have on the speed at which the water wheel turns?

WIND POWER – ENERGY FROM WIND

Wind power generates electricity in a very similar manner to hydropower. The most obvious difference is that a wind turbine uses the wind instead of water to turn blades. These blades turn an axle that is connected to a generator to transfer the energy that is in the air to a more usable form.

About 2% of the energy coming from the sun is changed into wind energy. The winds are formed when air moves due to temperature changes and land and water temperatures around the world. The sun heats areas around the equator more than the rest of the world. This warmer air rises and travels in north and south directions towards colder regions of the world. However, because the Earth rotates in an eastward direction, the winds in effect travel in southwest and northwest directions.

The advantage of wind power is that it does not require any fuel source other than a steady flow of wind. The disadvantage to wind power is that is needs a forceful and steady supply of wind to work well.

ACTIVITY TWO: Power Generated by a Wind Turbine

Step 1: Orient the pinwheel in different positions in front and behind the fan.

1) In which location and position does the pinwheel turn the fastest?

2) Which direction does the pinwheel spin fastest (perpendicular or parallel)? Why?

[pic](perpendicular) [pic](parallel)

Step 2: Locate the pinwheel about one meter from the fan at the position that it spins the fastest at. Slowly stack books halfway between the pinwheel and the fan.

3) How does this affect the pinwheel?

Remove the books and slowly stack them up directly behind the fan.

4) Does this have an effect on the pinwheel speed?

From this experiment what can you state about the location to where a wind turbine would need to be placed to work the best?

Step 3: Hold the fan in the position that it works the best at and then reduce the speed of the fan to a lower setting. Turn the fan off for a little while and then back on.

5) What can you conclude about the reliability of wind power as an effective energy source?

GEOTHERMAL ENERGY – ENERGY FROM THE EARTH

Geothermal energy is energy that is captured from the heat given off by our own planet. It is the only alternative energy source that does not come from the sun. Heat is generated deep in the Earth. This heat naturally flows upward to the surface of the planet. While heat is traveling up, rainfall travels down and is trapped in porous rock. The heat from the Earth heats the water or turns it to steam. The heat energy is then drawn from the water or steam using heat pumps and exchangers. The steam and water can also return to the surface as geysers or hot springs.

The advantages of geothermal energy are that it does not produce pollution, take up much room, or require any fuel. A disadvantage of geothermal energy is that locations for plants are hard to find. There are only certain places with the right type of hot rocks at the right depth. Also, sometimes hazardous gases and minerals come up from underground and are difficult to safely dispose.

ACTIVITY THREE: Power Generated by Steam from the Earth

Step 1: Tie back hair and any loose clothing. Put on safety glasses. Clear the area of any papers. Place the candle in the aluminum tray.

Step 2: Fill the test tube with about 1.5 cm of water and stretch the balloon over the opening of the test tube.

Step 3: Have the teacher light the candle.

Step 4: Use the test tube clamp to hold the test tube over the flame. Gradually move the test tube in circles over the flame. Take caution to keep the test tube tilted away from you.

Step 5: Once the balloon starts to inflate, remove the test tube from the flame.

1) Why did the balloon begin to inflate?

2) What causes it to deflate?

3) Is the amount of water in the test tube after the experiment the same as or different from the amount in the beginning? Explain.

SOLAR ENERGY – ENERGY FROM THE SUN

Since the beginning of time, the sun has been the main provider of energy for our planet. It acts as a huge nuclear furnace that continually supplies our planet with an energy supply. This energy supply is called solar energy and provides Earth with about 1.5 quadrillion-megawatt hours of energy per year.

Solar power is absolutely essential for the existence of life on Earth. It provides warmth, energy for photosynthesis in plants, and the energy needed to drive winds and hydropower. Solar energy can be converted to other forms of energy, such as heat and electricity.

Solar cells are used to convert light energy to electricity by utilizing chemical reactions stimulated by sunlight. Some materials have the characteristic to absorb bundles of energy. A solar cell is generally made up of two layers of material to serve this purpose. One layer is a combination of silicon and arsenic. The other layer is a combination of silicon and boron. Solar cells operate better in higher light intensities, not in higher heat.

The advantages of solar energy are that the fuel source is unlimited, there is no pollution, and it can power anything from cars to satellites. The disadvantages of solar energy are that large land areas are required for large amounts of heat or electricity and that only areas of the world with lots of sunlight are suitable for solar power.

ACTIVITY FOUR: Power Generated by the Sun

Step 1: As a team, observe whether the calculator operates when you completely block the solar power panel.

1) What happens if you partially block the solar panel?

Step 2: Discuss five other products you can think of that are either completely or partially powered by solar panels.

Step 3: Hold the solar motor (the part with the fan blades) above the counter. Be Careful not to get YOUR Fingers caught!

Step 4: Turn on the light

Step 5: Hold the light directly above the solar panel angle it until you reach 45◦. Keep in mind that you may need to keep the solar panel and the light close together to make anything work.

2) At approximately what angle does the fan move the fastest?

3) Describe what you see (the different parts that make up the solar panel). Which part is responsible for transforming light into electricity?

BIOMASS ENERGY – ENERGY FROM LIVING MATTER

Biomass is living, or once living, mater in a raw or processed form. Trees, grasses, paper trash, yard clippings, sawdust, and agriculture waste such as rice and wheat straws, corn husks, and manure are all biomass energy materials. Much of the solar energy from photosynthesis is stored within the organic matter of the biomass material. Biomass materials can be waste garbage or fast-growing hybrid trees and are generally the materials that would naturally be wasted through food or lumber production.

The use of biomass as an energy source has been around for thousands of years, but it has not been used well. Newer and better processes are capable of using biomass to generate electricity and heat, and in producing fuels such as ethanol for motor vehicles and methane gas for burning. The use of biomass currently provides about 5-7% of the world energy and future use is predicted to increase as the search for alternative fuels increases.

The advantages to biomass are a reduction in landfills, better control of certain pollutants, reduction in soil erosion, and an increase in wildlife habitat. The disadvantages to biomass include pollutants from farming and competition with food production.

ACTIVITY FIVE: Power Generated by Biomass

Step 1: An estimated 350 million tons of farming and yard waste such as leaves are placed in landfills each year.

1) If this wasted biomass would be used for energy production, how much space could be saved? Assume that one bag of leaves weighs 10 pounds and takes up 1 cubic foot when compacted.

Conversion factor: 1 ton = 2000 pounds

2) Explain why leaves, corn stalks and manure are renewable resources.

Step 2: Some forms of gasoline today have a percentage of ethanol in them that is made from corn biomass. Approximately 20 billion barrels of oil are used world-wide each year.

3) Figure how many barrels of oil are saved each year by using a gasoline that contains 10% ethanol.

4) What if the fuel was 85% ethanol and 15% gasoline?

WASTE-TO-ENERGY – ENERGY FROM GARBAGE AND LANDFILLS

Garbage is the source of about 12% of the total biomass energy consumed in the United States. Garbage contains biomass materials like paper, cardboard, food scraps, grass clippings, leaves, wood, and leather products. Americans produce more and more waste each year. In 1960, the average American threw away 2.7 pounds of trash a day. Today, each American throws away about 4.5 pounds of trash every day. 14% of our trash is burned and 55% goes into landfills.

Today, we can burn garbage in special waste-to-energy plants and use its heat energy to make steam to heat buildings or to generate electricity. Many large landfills also generate electricity with the landfill’s methane gas that is produced as biomass decomposes in the landfills.

There are about 80 waste-to-energy plants in the United States that generate electricity. In 2008, these plants generated 14.5 million kilowatt-hours of electricity, about the same amount used by 1.3 million U.S. households. Today, there are almost 400 operating landfill gas energy projects in the United States. California has the most landfill gas energy projects in operation (73), followed by Illinois (36), and Michigan (27).

The major advantage of burning waste is that it reduces the amount of garbage we bury in landfills. The major disadvantages are that it actually costs more to generate electricity at a waste-to-energy plant than it does at a coal, nuclear, or hydropower plant and there can be harmful gases released into the air.

The major advantage of capturing methane gas is that it decreases the amount of methane our waste emits into the atmosphere. The major disadvantages are that it can currently only be used near landfills and the gas must be cleaned before used or it could be harmful to humans.

ACTIVITY SIX: Power Generated by Garbage

Waste-to-energy, also called recovery, is an environmentally safe process that burns common waste items to produce electricity. Twelve steps in the waste-to-energy process are below. However, they are out of order. Your challenge is to put the steps in the correct order. Complete the steps below on your answer sheet.

Step One: Use what you know to predict the correct order in the first column.

Step Two: Click through the Waste Management Interactive. Watch the video at waste-to-energy which outlines the correct steps, and write them in the second column.

Step Three: Highlight all steps that illustrate an energy conversion.

BRINGING IT ALL TOGETHER – INVESTIGATING RENEWABLE RESOURCES WITH

GOOGLE EARTH (FROM GENERAL MOTORS)

Welcome to the GM Education Google Earth Project. Travel the world and uncover the different types of energy people use to fuel their cars, power their homes and energize their gadgets and gizmos. This project highlights how General Motors uses renewable energy.

Navigating through this is easy. Click on the plus sign next to “Primary Energy Sources” and “Secondary Energy Sources” folders on the left to reveal more folders that showcase all the different types of energy we use and where they can be found around the world. The check marks can be turned on and off to turn the information on and off on the globe.

To see specific locations of where the energy type is used by General Motors, click the small plus sign to the left of the energy type and several locations will appear. Double click each location to move around the globe to the destination. The program may take a while to load each page. BE PATIENT, DO NOT KEEP CLICKING OR THE PROGRAM WILL LOCK UP.

ACTIVITY SEVEN: Investigating Renewable Energy

Step One: Make sure the boxes in the graphic to the right are checked and unchecked on Google Earth.

Step Two: Expand each of the five examples of renewable energy. In Google Earth “visit” at least one location example for each type of renewable energy. Click on the yellow pushpin to zoom to the location.

Step Three: Zoom in and look at the surroundings for each energy station you choose. Read the information.

Step Four: Write a brief description for each location you investigate in Google Earth.

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