Geoscientists gather and interpret data about the earth and other planets;  they use their knowledge to increase our understanding of the earth processes and to improve the quality of human life. Their work and career paths vary widely because the Geosciences are so broad and diverse.

The following list gives a glimpse of what geoscientists do in these disciplines and a variety of sub-disciplines:

• Atmospheric scientists study weather processes, the global dynamics of climate, solar radiation and its effects, and the role of atmospheric chemistry in ozone depletion, climate change, and pollution.
• Economic geologists develop metallic and nonmetallic resources; they study mineral deposits and find environmentally safe ways to dispose of waste materials from mining activities.
• Engineering geologists apply geological data, techniques, and principles to the study of rock and soil surficial materials and ground water; they investigate geologic factors that affect structures such as bridges, buildings, airports, and dams.
• Environmental geologists study the interaction between the geosphere, hydrosphere, atmosphere, biosphere, and human activities. They work to solve problems associated with pollution, waste management, urbanization, and natural hazards, such as flooding and erosion.
• Geochemists use physical and inorganic chemistry to investigate the nature and distribution of major and trace elements in ground water and Earth materials; they use organic chemistry to study the composition of fossil fuel (coal, oil, and gas) deposits.
• Geochronologists use the rates of decay of certain radioactive elements in rocks to determine their age and the time sequence of events in the history of the earth.
• Geologists study the materials, processes, products, physical nature, and history of the earth.
• Geomorphologists study Earth's landforms and landscapes in relation to the geologic and climatic processes and human activities, which form them.
• Geophysicists apply the principles of physics to studies of the Earth's interior and investigate earth's magnetic, electric, and gravitational fields.
• Hydro geologists study the occurrence, movement, abundance, distribution, and quality of subsurface waters and related geologic aspects of surface waters.
• Mineralogists study mineral formation, composition, and properties.
• Pale ecologists study the function and distribution of ancient organisms and their relationships to their environment.
• Paleontologists study fossils to understand past life forms and their changes through time and to reconstruct past environments.
• Petroleum geologists are involved in exploration for and production of oil and natural gas resources.
• Petrologists determine the origin and natural history of rocks by analyzing mineral composition and grain relationships.
• Sedimentologists study the nature, origin, distribution, and alteration of sediments, such as sand, silt, and mud. Oil, gas, coal and many mineral deposits occur in such sediments.
• Seismologists study earthquakes and analyze the behavior of earthquake waves to interpret the structure of the earth.
• Stratigraphers investigate the time and space relationships of rocks, on a local, regional, and global scale throughout geologic time - especially the fossil and mineral content of layered rocks.
• Structural geologists analyze earth's forces by studying deformation, fracturing, and folding of the earth's crust.