Earth Science and Its Branches

Lesson Objectives

  • Define and describe Earth science as a general field with many branches.
  • Identify the field of geology as a branch of Earth science dealing with the solid Earth.
  • Describe oceanography as a branch of Earth science that has several subdivisions that deal with the various aspects of the ocean.
  • Define meteorology as a branch of Earth science that deals with the atmosphere.
  • Understand that astronomy is an extension of Earth science that examines other parts of the solar system and universe.
  • List some of the other branches of Earth science, and how they relate to the study of the Earth.


Earth science is made of many branches of knowledge concerning all aspects of the Earth system. The main branches are geology, meteorology, climatology, oceanography, and environmental science. Astronomy uses principles understood from Earth to learn about the solar system, galaxy, and universe.

Overview of Earth Science

Only recently have humans begun to understand the complexity of our planet Earth. We have only known for a few hundred years that Earth is just a tiny part of an enormous galaxy, which in turn is a tiny part of an even greater universe.

Earth science deals with any and all aspects of the Earth: its lands, interior, atmosphere, and oceans. In all its wonder, Earth scientists seek to understand the beautiful sphere on which we live, shown in Figure below.

Earth as seen from Apollo 17.

Earth is a very large, complex system or set of systems, so most Earth scientists specialize in studying one aspect of the planet. Since all of the branches of Earth science are connected, these researchers work together to answer complicated questions. The major branches of Earth science are described below.


Geology is the study of the Earth’s solid material and structures and the processes that create them. Some ideas geologists might consider include how rocks and landforms are created or the composition of rocks, minerals, or various landforms. Geologists consider how natural processes create and destroy materials on Earth, and how humans can use Earth materials as resources, among other topics.

Geology has many branches, only a few of which are described in Figure below. As you learn about each branch of geology, think of an interesting question that you might like to try to answer.

(a) Mineralogists study the composition and structure of minerals and may look for valuable minerals. (b) Planetary geologists study the geology of other planets. Lunar geologists study the Moon. (c) Seismologists study earthquakes and the geologic processes that create them. They monitor earthquakes worldwide to protect people and property. (d) Scientists interested in fossils are paleontologists.


The study of water and its movements, distribution and quality is hydrology. Oceanography is more than just the hydrology of the oceans. Oceanography is the study of everything in the ocean environment, which covers about 70% of the Earth’s surface (Figure below). Recent technology has allowed people and probes to venture to the deepest parts of the ocean, but still much of the ocean remains unexplored.

Physical oceanographers study the movements of ocean water such as currents, waves, and tides.

Marine geologists learn about the rocks and geologic processes of the ocean basins. An animation of underwater high-resolution sonar can be found here: Marine biologists study life in the oceans.

Climatology and Meteorology

Meteorology includes the study of weather patterns, clouds, hurricanes, and tornadoes. Using modern technology such as radars and satellites, meteorologists are getting more accurate at forecasting the weather all the time (Figure below).

Meteorologists forecast major storms to save lives and property.

Climatologists study the whole atmosphere, taking a long-range view. Climatologists can help us better understand how and why climate changes (Figure below).

Carbon dioxide released into the atmosphere is causing the global climate to change.

Environmental Science

Environmental scientists study the effects people have on their environment, including the landscape, atmosphere, water, and living things (Figure below).

Every action people take has some effect on Earth’s environment.


Astronomers are interested in outer space and the physical bodies beyond the Earth. They use telescopes to see things far beyond what the human eye can see. Astronomers help to design spacecraft that travel into space and send back information about faraway places or satellites (Figure below).

The Hubble Space Telescope.

Lesson Summary

  • The study of Earth science includes many different fields, including geology, meteorology, oceanography, and astronomy.
  • Each type of Earth scientist investigates the processes and materials of the Earth and beyond as a system.

Review Questions

  1. What are three major branches of Earth science?
  2. What branch of science deals with stars and galaxies beyond the Earth?
  3. List some important functions of Earth scientists.
  4. What is the focus of a meteorologist?
  5. An astronomer has discovered a new planet. On the planet, she sees what appears to be a lava flow. With what type of scientist might she consult to help her figure it out?
  6. An ecologist notices that an important coral reef is dying off. He believes that it has to do with some pollution from a local electric plant. What type of scientist might help him analyze the water for contamination?
  7. Design an experiment that you could conduct in any branch of Earth science. Identify the independent variable and dependent variable. What safety precautions would you have to take?

Further Reading / Supplemental Links

Points to Consider

  • Why is Earth science important?
  • Which branch of Earth science would you most like to explore?
  • What is the biggest problem that humans face today? Which Earth scientists may help us to solve the problem?
  • How do the other branches of science impact Earth science?