20 internet investigations on Earth. Students investigate the Earth’s population: how many people there are on our planet, and kids, animals, trees, ants, cows. Students research building materials on Earth: the materials we use to build homes, shopping malls, fire stations, schools, churches, signs, fences. Students search online for information about recycling: what materials we can recycle, why we do it, and how it is done. And seventeen more projects: objects in space (stars, planets, moons,