Earth’s Four Spheres
- Earth & Space
- Ages 8–11 · Grades 3–5
What you’ll find out
- Earth can be described as four spheres: geosphere, hydrosphere, atmosphere and biosphere.
- The spheres constantly interact, for example through evaporation, rain and plant roots.
- A change in one sphere, such as a volcanic eruption, can affect all the others.
No sign-up and no real names. In the lesson you check your understanding as you read, and practise until it sticks.
Rock, water, air and life
Scientists find it helpful to think of Earth as four great systems, called spheres. The geosphere is the solid Earth: rocks, soil and the planet’s hot interior. The hydrosphere is all the water, whether in oceans, rivers, underground, frozen as ice or floating as clouds. The atmosphere is the layer of air that surrounds the planet. The biosphere includes every living thing, from bacteria to blue whales. These spheres constantly touch and affect one another.
How the spheres work together
The spheres constantly change one another. When the Sun warms the ocean, water evaporates into the atmosphere, then falls as rain that wears down rock in the geosphere. Plants in the biosphere take carbon dioxide from the air, draw water from the ground and grow in soil, while their roots slowly crack rocks apart. Animals breathe the air and drink the water. A change in one sphere can ripple through all the others.
Curriculum links: NGSS 5-ESS2-1 · Cambridge Primary Stages 4–6: Earth and space · NCERT Environmental Studies, Classes 3–5