the ground. About a third is reflected directly back into space by the atmosphere. The

time in which solar energy is available, is also the time we least need it least - daytime.

Because the sun's energy cannot be stored for use another time, we need to convert the

suns energy into an energy that can be stored.

One possible method of storing solar energy is by heating water that can be

insulated. The water is heated by passing it through hollow panels. Black-coated steal

plates are used because dark colors absorb heat more efficiently.

However, this method only supplies enough energy for activities such as washing

and bathing. The solar panels generate "low grade" heat, that is, they generate low

temperatures for the amount of heat needed in a day. In order to generate "high grade"

heat, intense enough to convert water into high-pressure steam which can then be used to

turn electric generators there must be another method.

The concentrated beams of sunlight are collected in a device called a solar furnace,

which acts on the same principles as a large magnifying glass. The solar furnace takes the

sunlight from a large area and by the use of lenses and mirrors can focus the light into a

very small area. Very elaborate solar furnaces have machines that angle the mirrors and

lenses to the sun all day. This system can provide sizable amounts of electricity and create

extremely high temperatures of over 6000 degrees Fahrenheit.

Solar energy generators are very clean, little waste is emitted from the generators

into the environment. The use of coal, oil and gasoline is a constant drain, economically

and environmentally. Will solar energy be the wave of the future? Could the worlds

requirement of energy be fulfilled by the "powerhouse" of our galaxy - the sun?

Automobiles in the future will probably run on solar energy, and houses will have solar

Solar cells today are mostly made of silicon, one of the most common elements on

Earth. The crystalline silicon solar cell was one of the first types to be developed and it is

still the most common type in use today. They do not pollute the atmosphere and they

leave behind no harmful waste products.

Photovoltaic cells work effectively even in cloudy weather and unlike solar heaters,

are more efficient at low temperatures. They do their job silently and there are no moving

parts to wear out. It is no wonder that one marvels on how such a device would function.

To understand how a solar cell works, it is necessary to go back to some basic

atomic concepts. In the simplest model of the atom, electrons orbit a central nucleus,

composed of protons and neutrons. E