MakerS as innovaTors Chapter 1 What Is Solar Energy t he sun is an important part of our lives even if we don’t think about it every day Its bright light allows us to see It provides us with a huge amount of energy In fact the amount of sunlight that reaches Earth each hour is more than enough to sat isfy the entire world’s energy needs for a whole year Have you ever thought of sunlight as energy 4
Solar EnErgy ProjEctS A tree takes energy from the sun and combines it with water from its roots to create oxygen which is released into the air and sugar which fuels the tree’s growth This energy conversion is known as photosynthesis If you have ever gone outside on a sunny day you’ve probably noticed the sun’s rays warming your skin Even on a cold day the difference in temperature between standing in the sun and standing in the shade is often noticeable That change in temperature is the energy in sunlight at work Sunlight warms you when you stand directly in the path of the energy 5
MakerS as innovaTors A plant can absorb energy from the sun through its leaves Art museums are extremely careful about where they hang their art This is partly because they know how much energy the sun contains Over time exposure to direct sunlight can cause the colors of a painting to fade As the various colors on a paint ing absorb and attract energy from the sun they are affected by the energy and slowly lose some of their brightness 6
Solar EnErgy ProjEctS Priceless works of art aren’t the only thing affected by the sun’s energy You may have noticed that posters or pictures hanging on your wall might begin to look a little faded over time You can do a simple experiment to see this effect firsthand Use your computer to type a few words in large black type on a single sheet of paper Print out two copies Hang one on a wall in your home where it will be exposed to direct sunlight on a regular basis Place the other one in a dark place After a couple of months the words on the paper hanging in the sun should begin to fade Compare it to the one in the dark to see just how much it has changed If you wait an entire year you may see the words disappear almost completely Plants are the original pioneers of solar power They use photosynthesis to convert sunlight and water into the food they need to live If you cover up a plant so it can’t get enough light it will eventually die Humans are not able to use photosynthesis However scientists have figured out how to turn sunlight into an energy source that can be used for a wide variety of purposes We can convert sunlight into thermal energy to heat our homes We can also convert it into electricity to power lights computers and other devices 7
