Earth's spheres & zones
Four inter-connected spheres
Atmosphere (air)
Lithosphere (stone)
Hydrosphere (water)
Biosphere (life)
is the body of air that surrounds and protects our planet.
Air of our planet is 78% nitrogen and 21% oxygen.
is the solid, rocky crust covering entire the planet.
This crust is in-organic and is composed of minerals.
is composed of all of the water on or near the Earth.
This includes the oceans, rivers, lakes, and even the moisture in the air.
97% of Earth's water is in the oceans. The remaining 3% is fresh water, three-quarters of the fresh water is solid and exists in ice sheets.
is composed of all living organisms. Plants, animals, and one-celled organisms are all part of the biosphere.
Most of the planet's life is found from 10 feet below the ground to 100 feet above it and in the top 1000 feet of the oceans.
How the spheres interact
All four spheres can be and often are present in a single location.
Interaction between the spheres is a constant, on-going series of exchange. These are needed to maintain and operate the entire natural Earth system.
Water cycle
It has no starting or ending point.
Air temperature determines whether this descending water forms rain, snow, sleet or hail which are the four main types of precipitation.
Water that soaks into the ground becomes part of what is known as groundwater. It's estimated that 15% of all fresh water on Earth exists as groundwater.
There is an extensive system of underground stream and rivers composing the groundwater, all of which eventually return water to the oceans.
Water that doesn't soak into the ground or evaporate but continues to flow across the Earth surface is called runoff. This water collects in streams, rivers, and some eventually flows into the ocean.
The importance of water
65% of our bodies are made up water. Without water, a person can't live for more than a few days.
Water is used for household purposes, industry, agriculture, transportation, to generate electricity, and recreation.
Conserving water and reducing water pollution will become even more important in the future as global population continues to grow and the clean, fresh water supply dwindles.