Lesson: What is Energy?Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Educational Standards :
Learning Objectives (Return to Contents)
After this lesson, students should be able to:
Introduction/Motivation (Return to Contents)
You cannot always see energy, touch it or hold it in your hand, but energy is everywhere.
Energy is the ability to do work, to make things happen, and to cause changes. Energy cannot be made or destroyed; it can only be changed into different forms. Can you name a form of energy? (Examples: Light, heat, electricity, sound) From where do you think we get electricity? (Possible answers: Power plant, the outlet in the wall, food) Can you think of an example in which energy is changed from one form to another? How about a light bulb? We turn it on by plugging it into the wall. What happens when you leave a light bulb on for a while? It gets hot! Well, that is an example of electrical energy changing into heat energy from the vibration of the filament, which also produces light!
Now, let's think about a gas-fueled electricity plant. A power plant produces electricity by changing the chemical energy in fuel into electrical energy. First, gas is burned within the plant, converting its chemical energy into heat. Next, the heat turns water into steam, which moves a turbine motor or generator. Finally, the generator produces electricity.
This steam-based technology was first discovered in the early 1700s when engineers began to figure out ways to use the energy in steam released by boiling water. They developed engines that converted steam energy into mechanical energy for use in farm and factory machinery, and later for trains and cars. Historians often cite the development of the steam engine as the start of a period in modern history called the industrial revolution.
We classify energy in two ways. First is potential energy, which is the amount of energy something has stored inside it. Anything can have potential energy. A battery has potential energy stored by a difference in ionic concentration; even you have potential energy, as you sit in your chair. How much potential energy you have depends on a few things, including how high up you are and how big you are. Next is kinetic energy. Kinetic energy is the energy of an object in motion. Anything that is moving has kinetic energy. Mechanical objects, such as a clock or a person on a skateboard, have kinetic energy, but so do light, sound, wind and water. Can you see examples of energy around the classroom? Well, today we are going to find some of these examples and learn about how engineers work with different types of energy.
Write the following phrases on the board and discuss with the class.
What is energy?
- Force can put matter into motion or stop it if it is already moving.
- Motion is a change in position of an object with time.
From where does energy come?
What are different types of energy? (See the Vocabulary / Definitions section.)
How do we use energy?
Lesson Background & Concepts for Teachers (Return to Contents)
Energy takes many forms. Thermal energy (or heat) boils water, keeps us warm and drives engines. Chemical energy fuels automobiles and airplanes. Electrical energy drives many small machines and keeps lights glowing. Almost every form of energy can be converted into other forms. But whatever form it is in, energy is essentially the capacity for making something happen or, as engineers and scientists say, "doing work."
Nearly all our energy comes to us ultimately from the sun (see Figure 1). We get some energy directly via passive solar lighting and heating, or solar power cells. However, most energy comes indirectly via burning fossil fuels (coal, oil and gas), which received their energy from fossilized plants and other organisms. The plants and organisms originally obtained their energy directly from the sun by a process called photosynthesis. Some of these sources of energy are renewable and others nonrenewable or limited in their available quantity.
Vocabulary/Definitions (Return to Contents)
Associated Activities (Return to Contents)
Lesson Closure (Return to Contents)
Today we started learning about energy and engineering. Can you define and describe the word "energy?" What types of energy can you see, feel or hear? (Possible answers: Heat, light, sound, movement.) Why would an engineer care about energy? (Answer: Engineers develop products that use energy. Engineers help develop ways to store energy for our use.)
Assign students the attached Energy Vocabulary Quiz to gauge their mastery in understanding the uses of energy in their surroundings and the fundamental types of energy.
Attachments (Return to Contents)
Assessment (Return to Contents)
Discussion: Ask the students the following questions:
Take-Home Definitions: Ask students to ask several members of their families for definitions of a specific energy form, and then look up the definition in the dictionary. Have them write down comparisons of these definitions and a reason why each might be different. Share these explanations with the class.
Lesson Summary Assessment
Energy Identifier: Bring to class examples or images of the following objects. Have students identify the type of energy that is related to each item. You could set up stations around the room or turn it into a game in which the students earn points for each type of energy correctly identified.
Vocabulary Review: Assign students the attached Energy Vocabulary Quiz to gauge their understanding of the ways energy is used in their surroundings and the fundamental types of energy.
Lesson Extension Activities (Return to Contents)
Have students research the source of your local utility company's electricity. Is it coal, natural gas, hydro, nuclear, wind or some combination? Many local utility companies provide detailed websites and extensive K-12 outreach programs for schools. A representative may even come to your classroom or lead a field trip.
For students with a high reading comprehension, use the attached Energy Vocabulary Worksheet to reinforce their understanding of the material.
References (Return to Contents)
Consumer Energy Center, California Energy Commission. Accessed September 14, 2005. (information on energy efficiency, alternative fuel vehicles, renewable energy) http://www.consumerenergycenter.org/index.html
Energy Kid's Page. Energy Information Administration, U.S. Department of Energy. Accessed September 14, 2005. ( energy facts, fun & games, energy history, classroom activities) http://www.eia.doe.gov/kids/
Energy Quest: Kid's Page. Updated 2004. California Energy Commission. Accessed September 14, 2005. (Fun, interactive website for kids and teachers) http://www.energyquest.ca.gov/index.html
Graham, I., Taylor, B, Farndon, J. and Oxlade, C. Science Encyclopedia, 1999, pp. 78-90.
Science Projects. Updated March 14, 2005. Energy Quest: Kid's Page, California Energy Commission. Accessed September 14, 2005. (science projects and energy activities for K-12 students) http://www.energyquest.ca.gov/projects/index.html
ContributorsSharon D. Perez-Suarez, Natalie Mach, Malinda Schaefer Zarske, Denise Carlson
Copyright© 2005 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.