For thousands of years people have used heat from the sun to warm their houses, heat water, and cook food. In ancient China they used mirrors to reflect sunlight to start fires. More recently people have discovered ways to turn light from the sun into electricity.
Power that comes from the sun is called solar energy. It’s free, and it’s very clean as it does not create air pollution or other forms of waste. Small solar panels are often used to power electronics such as calculators and outdoor lights. You may have also seen larger solar panels on the roofs of houses. This means that the house is getting at least some of its electricity from solar energy.
The sunlight that shines on the earth during just one hour contains enough energy to power every single home for an entire year! You may be wondering then why everything isn’t powered by the sun? Just because the sun’s energy is there doesn’t mean we are able to collect it all. Solar panels cannot cover all the places on the earth. There are other problems, too. Solar energy is sometimes unreliable. The amount of sunlight changes due to the season, the time of day, and the weather. But people need electricity at all times, not only when the sun is shining.
Each year scientists are improving solar panels so that they can collect more of the sun’s energy. They are becoming cheaper to buy and make, too. The day might soon arrive when every house and car is powered with solar energy.