Fourth Grade
Worksheets
Geologist
Have you ever looked closely at a rock and wondered what it was made of? Have you wondered how rocks form? Geologists are scientists who study Earth's rocks, soil, and minerals. They study Earth's crust. They study earthquakes, volcanoes, and mountains. Earth's history is recorded in its rocks. Geologists know how rock layers form. By looking at many layers of rocks, they know what the Earth was like when those rock layers were laid down. The oldest rocks on Earth are about 3.9 billion years old. That is a very long time! The Earth has changed over so much time. Continents moved around. Mountains formed. Wind and rain eroded them. Bits of rock were .....
