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Kinetic Energy

The Kinetic Energy MatchCard provides hands-on demonstrations and explanation of actual and potential energy.

science-matchcard

Two Types of Kinetic Energy

Objective: Compare potential and actual kinetic energy.

There are two types of energy:

Actual Energy: The energy of a moving object
Potential Energy (or gravitational potential energy): The stored energy of a non-moving object.

So you don't think potential energy is really energy? Imagine you are standing under a heavy branch of an old oak tree that is full of snow. You start to hear a cracking sound as the weight of the snow begins to weaken the branch. Feel like moving? Could we say you have some potential energy overhead?

Let's Experiment

You will need the following:

a string (yarn or tooth floss will work)
nuts and bolts of two or more sizes/weights
a small toy car or rolling object

Perform the following steps:

1. Tie one end of the string around one of the bolts.
2. Hold the string so that it is dangling behind the toy car which is on the floor or table.
3. Keep our hand holding the string steady and in the same place. Now hold the bolt and pull it so it is at a 180% angle and parallel to the floor. The string should be held tight in a straight line.
4. Let go of the bolt so it falls and hits the car.
5. Measure how far the car travels.
6. Repeat the steps above with the same bolt, but different sizes of string. Note that the longer the stringer, the further it falls, the faster the speed, and the greater the energy.
7. Repeat steps 1 - 5 again, but with different masses of bolts. (It would be idea if you have two of the same size but different masses.) The greater the mass, the greater the energy.

Gravitational Potential Energy

Potential energy is the stored energy. When you were holding the bolt, gravity gave the bolt potential energy.

In the example above, the snow-filled tree branch had potential energy. Can you think of other examples of potential energy?

A glass of milk near the edge of a table
A rubber band that is stretched
A wind up toy that is wound up

Make a list of other examples of potential energy.

Actual Energy

Actual energy is the energy of a moving object. It occurred as the bolt was moving.

Can you think of other forms of actual energy?

Windmill
Paddleboat
Rubber band that has been released
Avalanche

Make a list of examples of actual energy.

The Kinetic Formula

Two factors increase the amount of energy in a moving object:

Mass of the object
Speed of motion

The formula for the energy of motion is:

E_K= (1/2)mv²

What's that supposed to mean?

Kinetic Energy = (1/2 the mass of an object) X (the velocity squared)

Using the Kinetic Energy Matchcard

This is the fifteenth Matchcard of the Light and Energy Unit Study. You can download the Kinetic Energy Matchcard here.

The student matches the description of actual and potential energy with the illustration.

The second page is the Instructor's Guide with the correct answers.

The third page has the Information Pieces. Student's cut them apart and place them in the correct place on their copy of the Matchcard (first page.)

For more information on how to use the Matchcards, see the MatchCard Science Instructor's Guide.

MatchCard Science

The activities and illustration above are from MatchCard Science, a homeschool science unit study. For the complete Light and Energy Unit Study follow this link. This unit study provides:

hands-on demonstrations
MatchCard reviews to master the material
suggestions for science projects to complete
instructions on a complete unit study curriculum

Currently this curriculum is under-going revision. We are providing free access to the unit study, with the desire that you will provide feedback as you are field testing the materials.

Science Notebook

When you are doing the experiment above, add your measurements to your science notebook. It is a great way for students to demonstrate their comprehension of scientific principles.

Return from the Kinetic Energy Matchcard to the MatchCard Science Main Page.