Geology is a branch of natural science that studies the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Geologists investigate the structure of the Earth on and beneath its surface and the processes that have shaped that structure. They study the mineralogical composition of rocks to gain insight into their history of formation and determine the relative and absolute ages of rocks found at a given location. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. Geology provides evidence for plate tectonics, the evolutionary history of life, and the Earths past climates.

Geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding natural hazards, remediating environmental problems, and providing insights into past climate change. It is a major academic discipline and is central to geological engineering and plays an important role in geotechnical engineering. Geology is a huge science that overlaps with other sciences, maths, and engineering. Geology is part of education at all levels and promotes observational skills, awareness of the whole earth and all the interconnecting systems, and an understanding of data and maps.

Geologists can specialize in various subject areas such as mineralogy, geodesy, and stratigraphy. They can work in various fields such as academia, government, and industry. Geology can be a very interesting and rewarding career, and the minimum training required is a four-year college degree in geology. Pre-college students who are interested in becoming geologists should take a full curriculum of college preparatory courses, especially those in math, science, and writing. Courses related to computers, geography, and communication are also valuable.