Geologists study the composition, structure, and history of the earth's crust. They try to find out how rocks were formed and what has happened to them since their formation. Geophysicists use the principles of physics and mathematics to study not only the earth's surface but its internal composition, ground and surface waters, atmosphere, and oceans as well as its magnetic, electrical, and gravitational forces. Both, however, commonly apply their skills to the search for natural resources and to solve environmental problems. Geologists and geophysicists often specialize.
Geological oceanographers study and map the ocean floor.
They collect information using remote sensing devices aboard surface ships or underwater research craft. Physical oceanographers study the physical aspects of oceans such as currents and the interaction of the surface of the sea with the atmosphere. Chemical oceanographers study the chemical composition, dissolved elements, and nutrients of oceans. Hydrogeologists study the distribution, circulation, and physical properties of underground and surface waters. They study the form and intensity of precipitation, its rate of infiltration into the soil, and its return to the ocean and atmosphere.