SOLAR ENERGY

     Scientists estimate that the sunlight falling on the United States during a single summer day contains twice as much energy as our nation uses in an entire year! The problem is how to collect this “free” energy in an efficient, econom- ical manner.

     The two experiments that follow demonstrate two direct methods of capturing solar energy. In other words, these methods transform sunlight itself into useable forms of energy: heat (Experiment 1) and electricity (Experiment 2).

     However, energy from the sun can also be collected indirectly. For example,“windmills” (Experiment 3) and ocean thermal energy systems (Experiment 4) convert the effects of sunlight into energy. The effects are wind and warm water. Sunlight provides the heat that makes the wind blow and warms the top layers of ocean waters.

Solar energy has many advantages:

• It is a clean, inexhaustible source of energy that will last as long as the sun itself.
  
• It is available in our own country. We don’t have to “import” sunlight.
  
• In remote areas it is more practical and less costly than stringing transmission lines.

But solar energy also has serious disadvantages:

• Solar energy“turns off” at night and during cloudy weather.
  
• Solar energy is at its weakest during the winter months, when homes and factories need energy the most.
  
• It is expensive.

     However, the potential benefits of solar energy outweigh its shortcomings.And major research programs are underway all over the world to make solar energy practical.