How do geologists study processes that happened hundreds of thousand years ago? By following the advice of James Hutton, an 18th century Scottish geologist, who said that “the present is the key to the past”. For example, an oil company may hire a geologist to figure out the best place to drill based on the types of rocks in the area under consideration. She does this by using equipment designed to measure radiation deep in the soil to determine if it contains organic material, a sign that it may yield oil or natural gas. Her decision to drill in one place and not another is based on the types of rocks on the surface.

Other geologists turn Hutton’s advice on its head. They might be hired by the management of a city situated near a volcano or a fault figure out the safest place to locate a new road or shopping complex based on that area's history of lava flow or earthquake activity.

Geologic specialties include but are not limited to mineralogy, volcanology, and hydrology. College students should be prepared to get at least a masters degree in geology if they want to go beyond entry level in the field. An advanced degree could lead to careers in education or pure research. High school students thinking about pursuing a geology major in college should concentrate their studies on science, math, and computer courses and, surprising, language arts. That's because reporting on the information learned in the field is as important as learning it.