Understanding the Sun, Earth, Moon relationship is the most important part of Unit 4. So before teaching my students about it, I had them make a hypothesis about their relative sizes, distances, and movement. Most students created a model like this one below, similar to what is often found in science textbooks.
But the true scale of our solar system defies common wisdom. In reality, if the sun were shrunk to the size of a softball, the Earth would be about the size of a pencil tip and the moon would be the size of a grain of sand. Not only that, at that scale the objects would need to be placed about 70 feet apart! And what lies between is the vast, empty expanse that we call “space.”