Students identify renewable and nonrenewable energy sources and investigate how farms can produce renewable energy. Grades 3-5

anaerobic digestion: a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen. One of the end products is biogas

biogas: a gas mixture, produced during anaerobic digestion that contains methane and carbon dioxide. Biogas can be burned as an energy source

biomass energy: power produced from plants and animals

coal: a rock that contains energy stored by plants that lived hundreds of millions of years ago

digestate: a nutrient-rich substance produced by anaerobic digestion that can be used as fertilizer

energy source: a material that can be used to produce power

fertilizer: any material of natural or synthetic origin that is applied to soils or plant tissues to supply one or more nutrients essential to plant growth

geothermal energy: power created from heat inside the Earth

global warming: a gradual increase in the overall temperature of the Earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide and other pollutants

kinetic energy: the energy of motion

manure: animal waste used for fertilizing land

natural gas: a hydrocarbon gas mixture which originated from microscopic plants and animals that lived millions of years ago

nonrenewable energy: energy that comes from resources that take longer than a person's lifespan to be replaced

nuclear fuel: a material (typically uranium from the ground that is processed) used in nuclear power stations to produce heat to power turbines and generate electricity

oil: a liquid fossil fuel formed millions of years ago when living organic matter died and was buried before it could decompose

pollution: a substance introduced into the environment that is dirty, unclean, or has a harmful effect

renewable energy: energy that comes from resources that can be replaced at the same rate in which the resource is used

solar energy: the light and heat that comes from the sun

switchyard: an enclosed area of a power system containing the switchgear

transformer: a device that transfers electrical energy from one electrical circuit to another; reduces or increases the voltage of an alternating current

wind energy: power that is generated directly from the wind

wind turbines: a device that turns the wind's kinetic energy into electrical energy

An energy source is a material that can be used to produce power. There are two major categories of energy—renewable and nonrenewable. Nonrenewable energy is energy that comes from resources that take longer than a person's lifespan to be replaced. Renewable energy is energy that comes from resources that can be replaced at the same rate in which the resource is used.

Nonrenewable energy sources include:

• Coal: Coal is a rock that contains energy stored by plants that lived hundreds of millions of years ago. Coal is used as fuel to generate power.
• Oil: Oil is a liquid fossil fuel formed millions of years ago when living organic matter died and was buried before it could decompose. It is extracted from the ground and used for fuel and to generate electricity.
• Natural Gas: Natural gas is a hydrocarbon gas mixture which originated from microscopic plants and animals that lived millions of years ago. It is found deep in the earth and is used for electricity, heat, and fuel.
• Nuclear Fuel: Nuclear fuel is a material (typically uranium from the ground that is processed) used in nuclear power stations to produce heat to power turbines and generate electricity.

Renewable energy sources include:

• Solar Energy: Solar energy is the light and heat that comes from the sun. The sun's energy can be harnessed to create electricity, to make hot water or steam, or to heat the inside of a building.
• Wind Energy: Wind energy is power that is generated directly from the wind. The wind's energy can be harnessed to create electricity or to do other work, like milling or pumping.
• Water Energy: Water energy is the power created from moving water. Water's energy can be captured from the movement of rivers using hydroelectric dams, waves, or tides to create electricity.
• Geothermal Energy: Geothermal energy is power created from heat inside the Earth. The energy can be captured through geothermal power plants or heat pumps to create electricity or heat water or buildings.
• Biomass Energy: Biomass energy is power produced from plants and animals. This energy can produce electricity and be converted into biofuels like biodiesel, biogas, and ethanol.

Renewable energy can protect the environment by helping to reduce pollution and global warming. It can decrease our dependency on other countries for imported fuels and can create new jobs. Renewable energy is a reliable source of power.

In addition to growing crops and/or raising animals, some farms create electricity from wind energy. Wind farms use wind turbines to capture the energy from the wind. Wind turbines have rotor blades that catch the wind and spin. A generator converts the kinetic energy of the wind into electricity, and a power cable carries the electricity down the tower to a transformer. The transformer increases the voltage and a switchyard delivers the electricity to consumers.

Some farms use solar energy to power water pumps or buildings. Light and heat from the sun produces solar energy. When sunlight hits a semiconductor on a solar panel, tiny particles called electrons create an electric current (DC) which is harnessed by the cell's wires. The current flows to an inverter, which converts DC electricity to AC. The AC electricity flows to the electrical panel, which directs the current to any appliance that is using electricity.

Farms can also create electricity and fuel from biomass, an energy resource that comes from plant or animal materials. One source of biomass energy is manure. Anaerobic digesters are used to convert manure into heat, electricity, and fuel. Manure from farm animals is collected and pumped into the digester. Microorganisms break down the organic material and produce biogas and digestate. The energy in the gas is converted to heat, electricity, and fuel for vehicles. The digestate is used as animal bedding and fertilizer.

1. Ask the students, "What is an energy source?" After listening to the students' answers, clarify that an energy source is a material that can be used to produce power.
2. Read Energy Island by Allan Drummond. Ask the students to raise their hand each time the story mentions a source of energy. Make a list of the energy sources on the board:
   • oil
   • electrical power plant
   • Ride bicycles 
   • heat from the sun (solar power)
   • oil from crops (biomass)
   • burn straw and wood (biomass)
   • wind energy
   • canola fuel (biomass)
   • solar panels
   • biomass furnace
   • windmill
3. After finishing the book, refer to the list on the board and ask the students, "Which energy sources have a connection to agriculture?"
4. Explain to the students that they will be investigating how farms can produce energy. 

Activity 1: Renewable and Nonrenewable Energy Sources

1. Organize the class into small groups. Provide each group with a set of Energy Cards. Instruct the groups to read the definitions of renewable and nonrenewable energy and the information on each energy source card. They should determine if the energy source is renewable or nonrenewable and place each card under the correct term.
2. To check and see if their energy sources were correctly sorted, show the students the Differences between Renewable and Nonrenewable Resources video. Allow time for the students to sort their cards again if necessary.
3. As a class, discuss the advantages of renewable energy: 
   • Renewable energy can protect the environment by helping to reduce pollution and global warming.
   • Renewable energy can decrease our dependency on other countries for imported fuels.  
   • Renewable energy can create new jobs.
   • Renewable energy is a reliable source of power.
4. View the Renewable Energy 101 video to discover more about the advantages and challenges of renewable energy.

Activity 2: Harnessing the Power of Wind

1. Read The Boy Who Harnessed the Wind (Picture Book Edition) by William Kamkwamba and Bryan Mealer. Use the following questions to discuss the story:
   • What were some of the challenges Malawi faced?
   • How can weather impact crops?
   • How did Malawi's curiosity help him?
   • How did Malawi harness the power of the wind?
   • Why did Malawi want to harness the wind?
   • What would your life be like with no electricity? 
2. Project the Engineering Design Process Graphic onto a large screen and discuss the elements with the students:
   • Ask to identify the need and constraints. Engineers ask critical questions about what they want to create: What is the problem? What do we want to design? Who is it for? What do we want to accomplish? What are the project requirements and limitations? What is our goal?
   • Research the problem. This includes talking to people from many different backgrounds and specialties to assist with researching what products or solutions already exist, or what technologies might be adaptable to your needs.
   • Imagine possible solutions. Work with a team to brainstorm ideas and develop as many solutions as possible. Encourage wild ideas and defer judgement. Stay focused on the topic, and have one conversation at a time. Good design is all about teamwork.
   • Plan by selecting a solution. Revisit the needs, constraints, and research from the earlier steps, compare your best ideas, select one solution, and make a plan to move forward.
   • Create a prototype. Building a prototype makes your ideas real. Early versions of the design solution help your team verify whether the design meets the original challenge objectives. Push yourself for creativity, imagination, and excellence in design.
   • Test the prototype. Does it work? Does it solve the need? Communicate the results and get feedback. Analyze and talk about what works, what doesn't, and what could be improved.
   • Improve and redesign. Discuss how you could improve your solution. Make revisions. Iterate your design, continuously improving it, to make your product the best it can be within your design constraints.¹
3. View the Wind Power 101 video.
4. Organize the students into small groups and challenge each group to design and build a wind turbine that will generate electricity for either a poultry, dairy, pig, horse, or sheep barn. (See the Let's Raise a Barn lesson to learn more about different types of barns.)
5. Provide each group with a Wind Turbine Diagram. Lead a discussion about how a wind turbine works:
   • The rotor blades catch the wind and spin.
   • The generator converts the kinetic energy of the wind into electricity.
   • The power cable carries the electricity down the tower to the transformer.
   • The transformer increases the voltage.
   • The switchyard delivers the electricity to consumers.
6. Explain to the groups that they will need to construct a barn, using paper or cardboard, and create a wind turbine that produces electricity for the barn (lights up an LED light) using the materials provided. The wind turbine will need to include:
   • A rotor with blades spun by wind from a fan
   • A motor
   • Positive and negative wires
   • A tower
   The barn will need to include:
   • Four walls
   • A roof
   • At least one window through which an LED light powered by the wind turbine can be seen
7. Provide each group with a mini DC electric (hobby) motor, 1 positive wire, 1 negative wire, an LED light, and access to materials such as paper, cardboard, paper towel rolls, paper cups, plastic cups, 2-liter soda bottles, Legos, wood dowels, popsicle/craft sticks, corks, paper plates, wood skewers, push pins, paper clips, toothpicks, tape, etc. Keep handy a drill with a drill bit that matches the size of the motor shaft and a hot glue gun for adult use.
8. Allow time for students to design, build, test, and improve their wind turbines. (The following wind turbine designs are useful for teacher reference: Build a Simple Wind Generator; Designing a Wind Turbine; Working Model of Wind Turbine to Generate Electricity; Wind Turbine Design and Testing Tutorial)
9. Have each group present their wind turbine to the class.
10. Discover more about how farmers use renewable energy by reading My Family's Wind Farm, a story about a family in Iowa who produces corn, soybeans, and electricity.

Activity 3: Running on Sunshine

1. Show the students the School Crossing Sign image. Ask, "How does the sign get power to light up?" (The sign is powered by solar energy—sunlight.)
2. Read Running on Sunshine: How Does Solar Energy Work? by Carolyn Cinami DeCristofano. Use the following questions to discuss the story:
   • Where does electricity usually come from? (Power stations. Electricity is generated from steam.)
   • What problems can power stations create? (The smoke from the fires used in power stations can create unhealthy air and changes in weather patterns.)
   • What do solar panels do? (They catch energy from the sun.)
   • Do solar panels always produce electricity? (No, they do not produce electricity when the sun is not shining, like at night or during a storm.)
   • Who are the people working on ways to store solar energy for times when the sun is not shining? (Engineers) 
3. Watch the What is Solar Power? video.
4. Have the students rejoin their groups from Activity 2 and challenge each group to add a solar panel to their barn that will generate electricity to power a fan.
5. Provide each group with a Solar Panel Diagram. Lead a discussion about how solar panels work.
   • Sunlight hits the solar panel and generates an electric current (DC).
   • The electric current flows to the inverter, which converts DC electricity to AC, the most commonly used form of electricity.
   • The AC electricity flows from the inverter to the electrical panel, which directs the current to any appliance in the building that is using electricity.
   • When the solar energy system produces more electricity than is needed, electricity flows through a utility meter to the grid. The utility meter records the amount of electricity that is sent from the solar energy system to the grid.
   • When the solar energy system produces less electricity than is needed, electricity flows from the grid, through the utility meter, to the electrical panel, which directs the current to any appliance in the building that is using electricity. The utility meter also records the amount of electricity that is sent to the building from the grid.
6. Provide each group with a solar panel, 2 test leads, a mini DC electric (hobby) motor, and a fan blade.
7. Allow time for the students to build and test their solar panels outside with sunlight.
8. Have each group present their barns with a working wind turbine and solar panel to the class.
9. Discover ways solar energy is used on farms by viewing the Solar-powered Well Pumps and/or Solar-powered Poultry Farm videos.

Activity 4: Biomass

1. Project the Biomass Image onto a large screen. Ask the students, "What do corn, algae, manure, and sugar cane have in common?" After listening to their responses, clarify that they can all produce energy like electricity and fuels.
2. Explain that an energy resource that comes from plant or animal materials is called biomass. One source of biomass energy is manure. View the Pig Poop Power video.
3. Have the students complete the Methane Digester activity sheet. Use the information from the video and activity sheet to discuss how a manure digester works: 
   • Manure from farm animals is collected and pumped into the digester.
   • Microorganisms break down the organic material and produce biogas and digestate.
   • The energy in the gas is converted to heat, electricity, and fuel for vehicles.
   • The digestate is used as animal bedding and fertilizer.
4. Use the following steps to create a small-scale model to demonstrate the science that is taking place in a methane digester:
   • Add 1 and 1/2 cups of warm water to an empty clear, plastic water bottle.
   • Add 3 tablespoons of yeast and 3 tablespoons of sugar.
   • Mix the water, yeast, and sugar together, and place a balloon over the end of the bottle.
   • As you perform each step, narrate the simulation. Manure from farm animals is flushed from the barn to covered lagoons (the water bottle). The manure is biomass (represented in the simulation with sugar). Anaerobic bacteria (represented by yeast) is mixed with the manure, resulting in a biogas that can be used to power generators and create renewable electricity.
   • Observe the changes that take place over the next 30-60 minutes.

After conducting these activities, review and summarize the following key concepts:

• An energy source is a material that can be used to produce power.
• Nonrenewable energy is energy that comes from resources that take longer than a person's lifespan to be replaced.
• Renewable energy is energy that comes from resources that can be replaced at the same rate in which the resource is used.
• Some farms create electricity from wind, solar, and/or biomass.

1. https://www.teachengineering.org/PDF/edp/TE_EDPTeacherMaterials_8.5x11.pdf
2. https://www.opusenergy.com/blog/13-little-known-facts-about-wind-energy/
3. https://www.energy.gov/eere/wind/how-do-wind-turbines-work

This lesson was created with support from Smithfield Foods, Inc. for National Agriculture in the Classroom. Smithfield has pioneered sustainability standards for more than two decades, including its industry-leading commitments to become carbon negative in U.S. company-owned operations and reduce GHG emissions 30% across its entire U.S. value chain by 2030. Visit the environment page to learn more about their goals.

Energy Cards Photo Credits:

• "Geothermal energy" by Peter Nijenhuis is licensed under CC BY-NC-ND 2.0 
• "Sugarcane Ethanol" by Sweeter Alternative is licensed under CC BY-ND 2.0 
• "Coal" by oatsy40 is licensed under CC BY 2.0 
• "Oil well pump jacks" by Richard Masoner / Cyclelicious is licensed under CC BY-SA 2.0 
• "Perry Nuclear Power Plant, Unit 1" by NRCgov is licensed under CC BY-NC-ND 2.0 

• Ag Today
• Energy Island
• Farming for Energy e-Magazine
• How Stuff Works: Corn Plastic
• Lab Investigation: Biodiesel
• My Family's Farm Book Series
• Packing Peanuts
• Pulp as Biodegradable Plastic in Disposable Food Containers
• Renewable vs Nonrenewable vs Inexhaustible Resources e-Magazine
• Solar Power Kit
• The Boy Who Harnessed the Wind
• Tootsie Roll Conversation About Conservation Terms
• Wind Power Kit