From the time she was old enough to pick one up; my daughter has been a rock collector. No matter where we went we would have rocks on the return trip. Sometimes the rock would be gravel from the parking lot – no matter, the rock was interesting or cool or pretty and she collected it. When we got ready to move, we found containers full of rocks – jars, boxes, bags, etc. As she got older she continued to be interested in rocks but expanded that interest to the broader discipline of geology and after learning about the Earth expanded again to include the planets.
Earth and Space science is an exciting part of learning for middle school and high school students. It offers both the tangible (rocks to hold in your hand) and the intangible (imaginings of the possible planets out there orbiting an alien sun). You can make theory real when almost any creek bed can show the layers of soil eroded by water. A lunar eclipse can be watched and studied on a clear night almost anywhere.