Hands-on Activity Energy Forms and States Demonstrations

Learning Objectives

After this activity, students should be able to:

• Describe at least three examples of how energy is converted from one form to another.
• State the law of conservation of energy.
• Identify seven forms and two states of energy.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

For teacher demonstrations (these items can vary, depending on availability of objects):

• balls (various weights, sizes)
• paper cups
• a few electrical or mechanical appliances
• battery-operated object

Introduction/Motivation

Energy exists in many forms all around us. The development of our modern society has been accomplished because scientists and engineers have learned to capture some of that energy and transform it into ways to do useful work. For example, the conversion of energy from a chunk of coal into steam and then into mechanical engines that can do heavy work was important in the 19th century and the industrial revolution.

Engineers must know where to "find" energy resources and then how to convert them into forms that are more useful for all of the machines and gadgets we use in our daily lives.

Look around this room: What tools or devices are using energy? Lights are a good example. They convert electric energy into light energy. What about this cup of water, (hold up a cup); does it have energy? It has a state of energy called potential energy because it is held up at an elevation. If the water is poured into a pail, the potential energy is released as the water moves with some velocity. This is a kinetic state of energy.

The goal of this class is to explore some critical terms that are needed for energy – forms of energy and states of energy.

Procedure

Before Class:

Organize all materials for the demonstrations; try out the demos to make sure they all work with your collected items.

With the students:

1. (Hold up a ball.) Does this ball have energy? (Expect students to say no.) (Then drop it.) Did it have energy as it fell? (Yes, work was done moving an object so energy must have been used.) Where did it come from? Can energy just be created and infused into the ball? (No. The ball DID have energy when it was held at a height above the floor. We call that potential energy. Since energy was put into lifting the ball into the air, aka calories were burned by the person lifting, we can see how the ball built up potential energy).

2. Introduce the concept of states of energy.

• potential (stored energy) (hold ball up)
• kinetic (energy in motion) (drop ball)

Consider giving students the equations for potential and kinetic energy to reinforce that mass, height and velocity affect the values.

PE = mass*gravity*height

KE = 1/2*mass*velocity²

3. Ask some exploratory questions with these demonstrations.

• If I drop a bowling ball and a golf ball from the same height, which has more potential energy? (the bowling ball) What about kinetic energy? (The bowling ball.)
• If I drop two golf balls from different heights, which has more PE? (The higher one.)
• If I drop one golf ball, and throw the other one down from the same height, which has more KE? (The thrown one because it has a higher velocity. Energy was put into getting the ball moving by the person.)

5. Reinforce the concept of potential and kinetic energy by doing a cup-crushing demo.

• Place a paper cup on the floor and hold a small weight or baseball, 6 inches above the cup.
• Drop the ball and point out that the ball starts out with potential energy and converts to kinetic energy,
• Repeat for a height of 12 inches and 36 inches. (Use some sort of tube or pipe to direct the weight so it stays on course!)
• Ask the students where the energy is coming from that is lifting the ball. Does it require more energy to lift the ball higher? (Answer: Calories burned by person lifting, and yes)
• Ask students to predict the behavior.
• Now use a bowling ball, or heavier weight.
• This is a good time to refresh (or introduce, if you did not get to it during the human power activity) the concept of acceleration due to gravity. Use the traditional "Newton experiment" with a baseball and a piece of crumpled paper.
• Have two students come to the front of the room; give one the ball and the other the paper (tightly crumpled). Ask the class to predict which one will fall to the floor faster when dropped? Why? (They both should hit the floor at the same time – the acceleration due to gravity is constant.)

6. All energy also has a FORM. The seven forms (NYS standards) are: sound, chemical, radiant (light), electrical, atomic (nuclear), mechanical, thermal (heat). Remembered as "SCREAM Today."

• sound – from vibration of sound waves
• chemical (fuel, gas, wood, battery)
• radiant (light) (note – this is part of the broader "electromagnetic" group)
• electrical energy (electrons move among atoms – as in the conductive wire of an electrical cord)
• atomic (nuclear) (from nucleus of atom)
• mechanical (walk, run)
• thermal (heat) (rub hands together)

Emphasize that electricity is a way or transporting energy, but is not an energy SOURCE.

7. Use various tools, appliances and materials to introduce students to the forms and states of energy. Possible demonstrations or discussion topics are electrical appliances (light bulb, blender, hairdryer, toaster, etc.); human movement; a fire; and a roller coaster. For at least a few of them, draw a process flow diagram that identifies the forms/states of energy going into the device and those coming out of the device. For example:

Point out:

• Some of the energy output from a device is the intended output – we want light from a light bulb. But we also sometimes get other forms of energy as output that is not desired. In this case, heat. When energy conversion devices are designed, engineers try to convert most of the energy that goes into the system into the intended output. Engineers are working to create light bulbs that produce more light energy and less heat. We describe these as more efficient light bulbs. That is one way to save energy – use more efficient devices. We'll learn more about efficiency in later lessons.
• Use a box to represent the item. Engineers do not usually draw the actual item when they are illustrating the flow of energy through an object.

Assessment

• If the mass of an object is 10 kg, and it is dropped from a height of 5 m, what is its potential energy? (Answer: PE=(10 kg)(9.8 m/s²)(5 m)=490 Nm) (A Nm (newton-meter) is equivalent to a (kg*m²)/s²)
• If the kinetic energy of an object is 100 Nm, and its velocity is 10 m/s, what is the mass of the object? (Answer: m=2KE/v² =2*100Nm/〖10 m/s〗² =2kg)
• Questioning: Use many opportunities throughout this activity to have students answer question related to forms or states of energy. The goal is to have students familiar enough with the terms and concepts so they can complete the energy conversion activity the following class period. That activity includes a student worksheet as a post-lesson assessment.

Other Related Information

This activity was originally published by the Clarkson University K-12 Project Based Learning Partnership Program and may be accessed at  http://internal.clarkson.edu/highschool/k12/project/energysystems.html.

Copyright

Contributors

Supporting Program

Acknowledgements

This activity was developed under National Science Foundation grant nos. DUE 0428127 and DGE 0338216. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.