An Earth Scientist is also known as Geoscientist. They specialize in the sciences related to the planet Earth. The four major disciplines in earth sciences, are geography, geology, geophysics & geodesy. These majors use the disciplines of physics, chemistry, biology, chronology & mathematics to build a quantitative understanding of the principal areas or spheres of the Earth system. Subdisciplines include: Atmospheric Science, Environmental Science,  Meteorology, Paleontology, & Water Science/Hydrology.