The Hydrosphere

Contributor: Hannah Brooks. Lesson ID: 12440

Have you ever thought of yourself as a fish? Maybe you don't live in the water like a fish, but you are surrounded by water! It's in the sky, the sea, and inside of you! Learn about this watery world!


Earth Science

learning style
personality style
Grade Level
Intermediate (3-5)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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Would you rather get bonked on the head with a water balloon or a snowball or a block of ice? Can you make lemonade with a cloud? Have you tried to walk on a swimming pool? Would you let your pet go a week without giving it water? Find out what water is made of and how important it is to all life!

Water can be found all over the planet — in the oceans, lakes, rivers, streams, and even underground.

We rely on water to stay hydrated. Our world is covered in water; in fact, approximately 70% of the Earth's surface is water.


Anywhere on Earth where we find water is called the hydrosphere. This includes water in the atmosphere, oceans, and glaciers.

water cycle

Why do you think it is called the hydrosphere? "Hydro" is a word that means "water," and dates all the way back to the ancient Greeks. Water is made up of two hydrogen atoms and one oxygen atom.

Why is water so important? Well, it is necessary to keep organisms alive. Water is able to dissolve other materials, like salts and sugars. The temperature of water doesn't change drastically without a good deal of energy, making it ideal for swimming.

There are three forms, or states, of water found in the hydrosphere: solid, liquid, and gas.

states of matter

  • Solid water exists in ice stored in glaciers, like at the North and South poles. Solid water also falls as snow or hail during winter precipitation events.
  • Liquid water is found in many more places, like under ground, flowing in rivers, filling up the oceans, and even in our bodies! Liquid water is able to move freely and can take the shape of whatever container it fills. Liquid water helps regulate the temperature of the Earth and coastal regions.
  • Gaseous water is found in the atmosphere and in the steam released from hot springs and geysers. Clouds are also made up of water vapor.


All water on Earth is part of the hydrosphere, from water vapor in the atmosphere to the water found in your local creek. Organisms live in water and rely on water to survive.

Remember, water is a tiny molecule made up of two atoms of hydrogen and one atom of oxygen. This combination makes it useful in regulating temperature and dissolving materials. Water can be found in three states in the hydrosphere: solid, liquid, and gas.

Discuss what you have learned with a parent or teacher before moving to the Got It? section, where you will practice identifying water found in the hydrosphere.

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