Geology is the study of the Earth and what it's made of, including its natural history.
Just as biology is the study of earth's life forms, geology is the study of the earth itself. Geology tells us where lakes once were, where volcanoes erupted, where glaciers pushed up mountains and then melted. Geologists — people who study geology — tell us where to find oil, coal and diamonds and then they explain how they got there. If you find the natural world beautiful and interesting, you might enjoy studying geology.