The Hydrosphere

Lesson Plan - Get It!

Audio:

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.

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.

• 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.