A solar-powered airplane finished its first international flight from Switzerland to Belgium. This is a big step for solar power. Solar energy is clean and useful and you can find it everywhere. But what is solar energy? How do we use it? Let's find out.
Have you ever seen houses with shiny boards on the roofs? Those families are using solar power.
Solar power converts (转换) the sun's energy which is said to be greater than the other energy used by all humans all the year. People can convert solar power into heat and electricity.
In the 1830s, British scientist John Herschel used a solar collector to cook food in Africa. This is said to be human's first try at using solar energy. Today, people use it for many things.
Solar energy can light streets, warm houses and heat water. Unlike other resources, the sun's energy will run out for billions of years.
Australian students from the University of New South Wales made a solar-powered car on their own. It reached a speed of 120 km per hour. The car uses the same amount of electricity as an oven (微波炉). Moreover, American scientists made a solar-powered nanosatellite (微型卫星). Scientists sent it into space in 2012 to try to find Earth-like planets.
However, solar power has its problems. The amount of sunlight that reaches the Earth's surface changes because of time and weather.
