# Lesson 1: What Is Energy?

## Day 2

### Activity 4: Kinetic and Potential Energy

Materials: marbles (kit), ruler with a groove in the middle (kit), thick book
Objects have two kinds of energy: kinetic and potential. Potential energy is the energy an object has because of its position. Potential energy is stored energy that is waiting to be used. Kinetic energy is the energy of a moving object. Watch the following video to learn more.
Next, put a ruler on top of a book, and hold a marble at the top of the ruler. The marble has potential energy at the top of the ruler. The higher you hold the marble on the ruler, the more potential energy the marble has. Now let the marble go. When the marble starts moving, the potential energy becomes kinetic energy. Kinetic energy is the energy of motion. Any moving object has kinetic energy. Discuss the following questions with a parent:
• Which has more potential energy: a skier at the top of the mountain or one that is half-way down? Explain.
• Does a rollercoaster going down a hill have kinetic or potential energy? Explain.
Find a parent or sibling and demonstrate your understanding of kinetic and potential energy. Use the marbles to demonstrate kinetic energy. Be sure to explain what kinetic energy is and how your demonstration is an example of it. Then think of a way to demonstrate potential energy using a book. Again, be sure to explain what potential energy is and how you are demonstrating it.

• Which has more potential energy: a skier at the top of the mountain or one that is half-way down? Explain.
• Does a rollercoaster going down a hill have kinetic or potential energy? Explain.
A skier at the top of the mountain has more potential energy. The roller coaster has both kinetic and potential energy. The movement downhill is kinetic energy. The position on the hill (above ground level) is potential energy. As the kinetic energy increases as the roller coaster goes down the hill the potential energy will decrease.

To demonstrate his understanding of kinetic energy, he might shoot one marble at the remaining marbles. Any marble that is moving has kinetic energy. For potential energy, he could simply hold the book or marble in the air. The book has potential energy in that position because if he lets go of it, it will fall and the potential energy will then become kinetic energy.

### Activity 5: Mechanical Energy

Materials: colored pencils or markers
Kinetic and potential energy are both forms of mechanical energy. An object has mechanical energy when it has either potential energy or kinetic energy. Often it has both at the same time! Think of the marble in Activity 4. While the marble was rolling down the ruler, it was also in the air. An object that is moving while in the air has both kinetic and potential energy at the same time. As the marble rolled and got closer to the ground, it gained kinetic energy but lost potential energy.

Read over the following options and choose one to complete.
Your child will select one of the options provided. In Option 1, he will illustrate potential and kinetic energy. In Option 2, he will think of ways to demonstrate both types of energy.

#### Option 1: Illustrating Mechanical Energy

On the "Illustrating Mechanical Energy" page, draw a picture to represent potential energy and one to represent kinetic energy. Your examples should not include ideas or pictures from the previous activity's demonstration or video.
Student Activity Page
If your child selects Option 1, encourage him to share his pictures of mechanical and potential energy.

#### Option 2: Demonstrating Mechanical Energy

Think of ways to demonstrate potential and kinetic energy. Record your ideas on the "Demonstrating Mechanical Energy" page. Your examples should not include ideas or pictures from the previous activity's demonstration or video. Demonstrate both types of energy to family members.
Student Activity Page
If your child selects Option 2, encourage him to demonstrate both types of mechanical energy to you or other family members. His examples should not include ideas or pictures from the previous activity's demonstration or video.

### Activity 6: Energy in Our Lives

Materials: scissors
Review the different forms of energy, and brainstorm a list of ways that energy impacts your life. Write your ideas down on a piece of paper. Then decide which forms of energy each one involves. Use the chart on the "Energy in Our Lives" activity pages to organize your ideas by listing each idea under the category (or categories) that it applies to.

Note that some of your ideas may only involve one form of energy, but many of your ideas will probably include multiple forms of energy. For example, drying clothes with a dryer would involve thermal, mechanical, and electrical energy, while drying clothes on a clothesline would use radiant energy.
Student Activity Page
Student Activity Page
Review your child's list of ways that energy plays a role in his daily life. Check to see that he sorted each idea into the appropriate category of energy.