This set of web pages is about making models of the Earth and our Moon to get a better understanding of their sizes and distances from each other. Models Are Useful Everyone uses models of things. Kids play with model people, houses, cars, airplanes, you name it, most toys are models of something.
Adults use models, too.
People who design buildings look at small models of what they are building to help them know how to construct it and how it will look when it's finished. Dentists make models of teeth that need fixing. Aeronautical engineers make models of airplanes to test them in wind tunnels. Models let you look at the whole thing all at once. You could fly to Greenland, get out of the plane and look around.