The surface of the Earth is made up of four parts. The parts are the atmosphere, hydrosphere, lithosphere, and the biosphere. The atmosphere is a layer of gas that surrounds the earth. The hydrosphere is the water that covers the surface of the earth. The lithosphere is the solid part of the earth’s surface. And, the biosphere is all the living things on the surface of the earth.
Parts of the Earth’s Surface
Lithosphere
A third of the Earth’s surface is solid continental land. The remainder of the Earth is covered with oceans. However, solid ocean floors lie beneath the water. The land and the ocean floors make up the Earth’s lithosphere.
The lithosphere is not one solid piece. It is broken up into large pieces called tectonic plates. These plates move slowly and collide with one another. The continents and ocean floors are parts of these large tectonic plates.
Movement of the tectonic plates creates landforms. This results in creation of mountain systems in continental areas. Below the oceans, plate movements can create deep undersea oceanic trenches.
Tectonic plates move slowly, but sometimes the lithosphere undergoes rapid changes. These sudden changes may result in volcanoes and earthquakes.
The Atmosphere
Composition: The surface of the Earth is covered by a layer of gas. This layer of gas is the atmosphere. The atmosphere is mostly nitrogen and oxygen gas. It also includes small amounts of other gases such as argon and carbon dioxide. A small but important part of the atmosphere is water vapor. Water vapor is water in a gas form.
Life: The gases that make up the atmosphere are important for life. Animals need the oxygen to breathe. Plants need carbon dioxide for photosynthesis. In addition, the atmosphere protects living things from dangerous forms of sunlight.
Climate: Finally, the atmosphere is responsible for the weather on the earth’s surface. The atmosphere influences the heating of the earth. The atmosphere influences the heating of the earth’s surface. This in turn drives rainfall, the winds and even the waves of the ocean.
The Hydrosphere
Water covers most of the earth’s surface. Liquid water makes up large oceans and seas. In addition, water makes up smaller lakes, rivers, and ground water. A small amount water exists as a gas (water vapor) in the atmosphere. Lastly, solid water exists as ice at the earth’s poles.
Water Cycle: The water cycle changes liquid water to water vapor and then back to a liquid again. This cycle produces clouds and rainfall. This cycle of water is essential for plant and animal life.
The Biosphere
Living things are found all over the earth’s surface. These plants and animals make up the earth’s biosphere. Living things are exist at high elevations, in deserts and in the ocean deeps.
Reflections
Vocabulary
- lithosphere
- hydrosphere
- atmosphere
Notes
- The surface of the Earth consists of four parts.
- The atmosphere is a layer of gas, while the lithosphere is solid.
- The hydrosphere is mostly liquid water and the biosphere is all living things.
