Solar Energy We can use the sun’s energy every day.
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Transcript of Solar Energy We can use the sun’s energy every day.
Nuclear Fusion
• The Sun is made up mostly of hydrogen and helium.
• It makes energy in its inner core in a process called nuclear fusion.
Solar Energy travels from the sun to the earth in rays.
Some are light rays that we can see. Some we can’t see, like x-
rays.
• Plants use the light from the sun to grow.
• Plants take the energy in light and store it in their roots and leaves.
• The energy feeds every living thing on earth.
Plants Depend on Solar Energy
We Depend on Solar Energy
• Sunlight turns into heat when it hits things. Without the sun we couldn’t live on earth- it would be too cold.
• All day, we use sunlight to see what we’re doing and where we’re going.
A car on a hot, sunny day becomes a solar collector. The car’s
windows let light in, but they don’t let all the heat out. A closed car
can get very hot!
Solar Cells
• Another type of solar collector is a solar cell.
• Solar cells turn light energy into electricity.
Solar Thermal Systems• Special collectors that
look like glass are mounted on the rooftop.
• Dark-colored metal plates inside the boxes absorb sunlight and change it into heat.
• Air or water flows through the collector and is warmed by the heat, which is then distributed through the house.
• Solar cells are Photovoltaic cells.
• Photovoltaic comes from photo, meaning light, and volt, a measure of electricity
• Electricity is produced when sunlight strikes the solar cell, causing electrons to move around. The action of the electrons starts an electric current.
Photovoltaic Cells
Examples of photovoltaic cells
are solar-powered
calculators and roadside telephone
call boxes.
Photovoltaic Cells
Solar Energy is Renewable
Solar energy is free and clean!
There is enough for everyone, and we will never run out of it!
Every day enough solar
energy reaches the earth to supply our
nation’s energy needs for a year!
Solar Energy is Renewable
The hard part is capturing enough sunlight.
The sun shines all over the earth, but only a little bit reaches any
one place.
On a cloudy day, most of the light never
reaches the ground at all.
Right now scientists are studying huge solar power towers as one possible
solution.
The Solar Tower laboratory at the Weizmann Institute of Science
Solar Power Tower
• Solar Power Towers capture sunlight to generate electricity.
• Each tower may have up to a thousand mirrors connected to it!
• Scientists are testing these towers for large-scale power grids.