Potential & Kinetic Energy

Teacher Page

Benchmark:

-Students will explore how energy changes (transforms) from one form to another within their surroundings.

-Students will communicate their knowledge of energy changes.

Objectives:

Students will learn about kinetic and potential energy and how they relate to each other and the ability to do work.

Materials:

• 3 marbles

• Ramp

• Metric ruler

• Plastic cup

• Energy worksheet

Initial Demonstration/Initial Observation:

Set up a demonstration of rolling three different marbles down an inclined plane. Place a plastic cup with a square piece cut out of the top upside down and at the bottom of the ramp to catch the marble(s) and then measure the distance that the cup moves each time.

Ask for hypotheses explaining why the cup moved different distances with the different amount of marbles or different angles of the incline plane.

Target Observations:

• The larger the mass the further the cup moves

• The higher the object is raised the further the cup moves

Target Model:

-The larger the mass and the higher an object is raised, the more energy is stored in that object.

Procedure:

Have the class split up into small groups of 4. Each group should receive a set of materials to work with. The groups will test the three different numbers of marbles ( masses) at the same height and one mass at three different heights.

If there is time, make a bar graph of mass vs. distance cup traveled and of height vs. distance cup traveled.

Discussion/Summary:

• Who can tell me the meaning of work? W=FxD

• What is mechanical energy?

• Which marble has more mechanical energy when sitting on a flat plane? Do your test results show this? The marble with the most mass

• If I put the marbles up on the inclined plane, would they have energy? Why? Yes, because above sea level

• When do the marbles have the most potential energy? The least? Most at a very high point and the least at sea level (PE=mgy)

• When do the marbles have the least kinetic energy? The most? Least at the most potential energy and the most when going the fastest (KE=1/2 MV2)

• What happens when the smallest marble is let go at twice the height of the larger one? Why? Do your test results show this? It will push the cup further.

• What are some examples of storing and using energy in our environment? Teeter-toter, Wrecking ball, Elevators

• What are some factors that affect the amount of work an object can do? Mass and Height

Target Revised Model:

-The larger the mass and the higher an object is raised, the more energy is stored in that object.

-Potential energy is stored energy (object is at rest)

-Kinetic energy is the energy used while moving

-When an object is put into motion, potential energy turns into kinetic energy

-When an object comes to rest, kinetic energy turns into potential energy

Name: Period:

Potential and Kinetic Energy

Student Sheet

Introduction:

Potential energy is energy that is stored in an object. If you stretch a rubber band, you will give it potential energy. As the rubber band is released, potential energy is changed to motion. Kinetic energy is energy of motion. A rubber band flying through the air has kinetic energy. When you are walking or running your body is exhibiting kinetic energy. Potential energy is converted into kinetic energy.

Materials:

• 3 marbles

• Ramp

• Metric ruler

• Plastic cup

• Energy worksheet

Problem:

Will the plastic cup move different distances with different amount of marbles and/or different angles of the incline plane?

Procedure: Record how far the cup travels for each of the three different masses of marbles.

Mass of Marble(s) / Distance Cup Traveled
1 Marble
2 Marbles
3 Marbles

Procedure: Record how far the cup travels for three different heights.

Height of the Inclined Plane / Distance Cup Traveled
Height 1
Height 2
Height 3

Graph:

Make a bar graph that illustrates the mass of marbles and the distance the cup traveled. Then make another bar graph that illustrates the height of the inclined plane and the distance the cup traveled.

Analysis:

1)  What is mechanical energy? Provide 1 example from the lab of mechanical energy.

2)  What is chemical energy? Provide 1 example from the lab of chemical energy.

3)  Describe momentum.

4)  Which marble has more mechanical energy when sitting on a flat plane? Do your test results show this?

5)  If I put the marbles up on the inclined plane, would they have energy? Why?

6)  When do the marbles have the most potential energy? The least?

7)  When do the marbles have the least kinetic energy? The most?

8)  What happens when the smallest marble is let go at twice the height of the larger one? Why? Do your test results show this?

9)  What are some examples of storing and using energy in our environment?

10)  What is work?

11)  What are some factors that affect the amount of work an object can do?

Conclusion: (4 sentences) – 4 points

What did you learn about kinietic energy, potential energy, momentum, and work from this lab activity.