Target Grade Level / Age Range:

6th-8th Grades


60-90 minutes (2 class period)

Virtual Learning:

Use this document to convert the lesson into a virtual learning module for your students. Use the steps outlined to create the different elements of a Google Classroom or other online learning platform. You can also send the steps directly to students in a PDF, present them in a virtual meeting, or plug them into any other virtual learning module system. 


Students will explore the process of biofuel production and how it relates to food chains.


Vocabulary (with definitions)

  • Ethanol – an energy source made from the sugars in plants
  • Biodiesel – an energy source made from plant oils
  • Energy – the ability to move people and things
  • Renewable resource – a source of energy that can be replaced
  • Food chain – the pathway of energy transfer through various stages as a result of the feeding patterns of a series of organisms
  • Food web – a diagram that shows the feeding relationships between organisms in an ecosystem
  • Apex predator – the predator on top of the food chain which no other predators predate 

Interest Approach or Motivator:

Ask students to create a Venn Diagram individually comparing the energy that humans need and the energy cars and trucks need. How are they similar? How are they different? What do they have in common?

This should be a challenging activity for students. They can be prompted with questions like:

  • Where do humans get their energy?
  • Why is it important that we have energy?
  • What are some things we couldn’t do without energy?  

Background – Agricultural Connections (what would a teacher need to know before teaching this lesson):

Iowa is the number one producer of ethanol and biodiesel. Ethanol is a fuel commonly made from corn that is blended with gasoline to power gasoline engines, like the ones in most cars. Biodiesel is commonly made from soybeans and is used to power diesel engines in trucks and busses. Ethanol and Biodiesel are considered renewable fuels because they are made from products that we can grow more of.

Ethanol is produced using #2 yellow dent (field) corn, which makes up approximately 99% of the corn grown in Iowa. Corn is planted in the spring, cared for by farmers all summer, and harvested in the fall. Farmers have to manage pests, diseases, weeds, and in some cases, weather to try and have the best corn crop they can. Then, the corn is usually sold or stored at a grain elevator, then sold to an ethanol plant. The plant will grind up the corn, ferment it with yeast, and collect the resulting ethanol. By-products from ethanol, like distillers grains, are often fed to livestock as part of a high energy ration.

Biodiesel is energy extracted from the oil in the soybean. Soybeans are grown similarly to corn; they are planted in the spring and harvested in the fall. They too are sold to grain elevators and then biodiesel plants. There, they are crushed and the oil is extracted, resulting in biodiesel.

Procedures (outline the main points, step by step activities, and the full content to be presented to students)

  1. To start class I will have the students discuss the following question, “Where does the energy ultimately come from which allows humans to function and runs our vehicles through the use of gas and ethanol?” Students will discuss with shoulder partners (people sitting on either side of them) again and then we will come together as a class to discuss how the energy for both processes ultimately comes from the sun.
  2. Students will then watch the “How ethanol is made” video and/or learn the steps of the ethanol process though the Ethanol and Agriculture PowerPoint.
  3. Without allowing students to discuss, introduce the idea of an “ethanol or biodiesel food chain” that will show the energy flow from corn or soybeans (the producers) to a car or truck. The students should diagram the process from the ultimate energy source (the sun) to the apex predator (the vehicle of students’ choosing). Students should include at least 4 steps in the process from the sun to the vehicle.
    1. Example steps would be sun -> growing plant -> plant harvested by farmer -> transported to ethanol plant -> ground -> fermented -> ethanol produced -> ethanol transported to gas stations and blended -> ethanol used to power cars
    2. Some of the intermediate level students may include the energy stored in the seed, or the addition of bacteria and enzymes to the corn mash, or even pictures of starch and alcohol molecules being made.
  4. Students should recognize that energy is used at various times in the chain. Have students circle any time that energy would be used and describe on their diagram what kind of energy is being used. Are there any points in the ethanol creation process that ethanol or biodiesel could be used? 
  5. Have students share their energy food chains with classmates around them or with the class. What steps are included? Why are they important? Are any important steps missing?
  6. Discuss with students that just like the food chains with organisms, there is an ultimate energy source for this ethanol food chain.  Ask them to discuss as a class what that would be (the sun).
  7. Bring up the idea that farmers are really using a renewable resource to grow their crops – the sun. What does that mean? How does energy from the sun affect farmers that grow livestock? How does it affect humans?

Essential Files (maps, charts, pictures, or documents)

  • Energy and Agriculture PowerPoint (IALF)

Extension Activities (how can students extend learning outside of the classroom? This could include assignments they do outside of class.)

  1. Students could do some research in a small report about other biomass alternatives such as lumber industry wastes, agricultural wastes, organic municipal wastes, food processing wastes, aquatic plants and algae, and municipal sewage.
  2. Iowa Agriculture Literacy Foundation’s Tassel to Tank lesson can be used to sequence and extend understanding of the steps in the ethanol making process.
  3. Have students research another form of renewable energy. They should write a paper either comparing and contrasting it with ethanol or persuading the reader to adopt that form of energy. 


  • James Sleep

National Agriculture Literacy Outcomes

  • T2.6-8.d.Identify renewable and nonrenewable energy sources.
  • T3.6-8.i. Identify sources of agricultural products that provide food, fuel, clothing, shelter, medical, and other non-food products for their community, state, and/ or nation.

Iowa Core Standards

  • Science
    • MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.
    • MS-LS1-6 Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
    • MS-LS1-7 Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism.
    • MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.
    • MS-PS1-3. Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.

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