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• Geology covers the rocky parts of the Earth (or lithosphere) including the planet's core, mantle, and crust. Major subdisciplines are geophysicsGeophysics the study of the earth by quantitative physical methods, especially by seismic reflection and refraction, gravity, magnetic, electrical, electromagnetic, and radioactivity methods. It includes the branches of: # Seismology ( earthquakes and ela, geochemistryThe field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the Earth's chemical c, paleontologyPaleontology (palaeontology is the British spelling) is the study of the developing history of life on earth, of ancient plants and animals based on the fossil record, evidence of their existence preserved in rocks. This includes the study of body fossils, mineralogyMineralogy is an earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. Studies also include the processes of mineral creation and destruction. The International Mineralogical Association is, petrologyPetrology is a field of geology which focuses on the study of rocks and the conditions by which they form. There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary. Igneous petrology focuses o, stratigraphyStratigraphy a branch of geology, is basically the study of rock layers and layering. It is primarily used in the study of sedimentary and layered volcanic rocks. The subject was essentially invented and first rigorously applied by William Strata Smith in and sedimentologySedimentology is the branch of geology concerned with understanding the characteristics of sedimentary rocks originally deposited in sedimentary basins. Sedimentary rocks cover most of the Earth's surface, record much of the Earth's history, and harbor th.

• Oceanography, limnology, and hydrology describe the marine and freshwater domains of the watery parts of the Earth (or hydrosphere). Major subdisciplines are physical, chemical, and biological oceanography.

• Atmospheric sciences cover the gaseous parts of the Earth (or atmosphere).

• Glaciology covers the icy parts of the Earth (or cryosphere)

However, given the numerous interactions between the spheres many modern fields take an interdisciplinary approach and thus do not sit comfortably in this scheme:

• Biogeochemistry follows the cycling of elements through the spheres mediated by biological and geological processes, and especially their distribution and fluxes between reservoirs.

• Paleoceanography and Paleoclimatology use the properties of sediments, ice cores, or biological material to infer past states of the ocean, atmosphere or climate.

Furthermore, other modern disciplines known collectively as Earth system science approach the entire Earth as a system in its own right, which evolves as a result of positive and negative feedbacks between constituent systems:

• Meteorology describes, explains and predicts the weather based on the interaction of principally the ocean and atmosphere.

• Climatology describes and explains the climate in terms of the interaction of the litho-, hydro-, atmo-, cryo-, and bio- spheres.

• Gaia theories explain the behaviour of the Earth system in terms of the influence of the biosphere.

Like all other scientists, earth scientists apply the scientific method: formulate hypotheses after observation of and gathering data about natural phenomena and then test those hypotheses. In earth science, data usually plays a critical role in testing and formulating hypotheses. The systems approach, enabled by the combined use of computer models as hypotheses tested by global satellite and ship-board data, is increasingly giving scientists the ability to explain the past and possible future behaviour of the Earth system.