Lesson 4: Heat and the Sun

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 winds. 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.

Remember that the Sun gives off heat and light energy. Plants need this energy to make their food, and we need energy from plants for our bodies. We also use energy to warm our homes, heat water, and cook food. Heat in homes may be provided through solar panels, natural gas, or electricity. How is the water in your home heated? How is your stove heated?

Scientists are trying to find inventive ways to harvest energy to heat homes and to fuel cars. Solar energy is becoming a popular way to harness energy that is environmentally friendly.

Conduct the experiment described on pages 30-31 of the book in your ScienceWiz Energy box. Share your Solar Spin with your family and describe how it works.

To see that solar energy really can provide valuable energy for work, create the Solar Racer described on pages 32-35 of the book in your ScienceWiz Energy box. Read about renewable energy in Appendix A on page 48.