Lesson 4: Heat and the Sun

Day 2

Activity 2: The Sun and Heat

Materials: dark colored clothing, light colored clothing, magnifying glass (kit), markers, white paper
NOTE: Have a parent help you with this activity.

There are many sources of energy, but most energy comes to us directly or indirectly from the Sun. Energy from the Sun heats the Earth's surface and the air above it. Sometimes this causes wind. Water evaporated by the Sun forms clouds and rain to give us flowing rivers and streams. Both wind and flowing water are sources of energy.

The energy from the Sun that we can see is light. Plants need this light energy to make their food, and we need energy from plants for our bodies.

Solar energy is becoming a popular way to harness energy that is environmentally friendly. Solar panels convert light energy into electricity that can be used to heat water and cook food.

Sunlight can also heat homes and water directly, without electricity, through special solar air and water heating systems. Even sunlight shining through windows can help warm houses and buildings.

In your own home, how is heat created to warm the water you use? How is heat created to cook your food? How is heat created to warm your home? Is energy from the Sun used in some way? Do certain windows allow enough sunlight in to noticeably warm the room?

In this activity you will change light energy into thermal energy and find out how the Sun heats the Earth. You will need a sunny day! Have a parent with you, too.
Student Activity Page
Student Activity Page
NOTE: As a precaution, supervise your child while she completes this activity. The paper will smoke lightly as it burns through where the black dot is, but there should be no flame.

In this activity your child will experiment with changing light energy into thermal energy. As the sunlight is focused onto the black dot, the light energy will create enough heat in the black dot to burn a hole through the paper.

Answers to questions:
  1. When you directed the Sun's energy onto the black dot, did the white paper get hot? Why or why not? (Not really, because it reflected a lot of the Sun's energy.)
  2. Why did the black dot burn? (The black color absorbed a lot of the Sun's energy, enough to cause the paper to burn.)
  3. If you wish, try this experiment again with different colored dots. Share your results with a parent. (Colors that are very close to black should absorb enough energy to burn through the paper.)

Activity 3: Solar Car

Materials: cardboard (kit), dowel rods (kit), gears (kit), hot glue gun or strong fast tack craft glue, lids (kit), motor (kit), solar panel (kit), straws (kit), tape
Radiant energy from the Sun is often referred to as solar energy. Build a solar car to see that solar energy really can provide valuable energy for work. This activity works best on a really sunny day. Try to run your car when the sunlight is strongest (depending on the season and where you live, this is often during the middle of the day). Follow the instructions on the "Solar Car" activity pages.
Student Activity Page
Student Activity Page
For this activity your child will make a solar car. Help her troubleshoot if she is not able to get her car to run. This activity works best on a very sunny day, so if your child's car doesn't run as well as she would like, have her try again on a brighter day, at a time when sunlight is at its most intense.