What is Water? | Types, Definition, Structure, Function & Facts

What is Water?

Water is one of the most crucial substances on planet Earth. All life forms need water to live. Water is constantly moving on Earth through the water cycle.

Like all “things”, water is made up of molecules. Have you heard of water called H2O? It is actually the chemical formula of the molecule that makes up water. H stands for hydrogen atom and O for oxygen atom. Each water molecule is made up of two hydrogen atoms and one oxygen atom.

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States of Water

We know that water is not always “wet”, sometimes it freezes into ice or snow. Depending on the temperature and energy of the water molecules, water can exist in 3 states:

Ice – Ice is the solid form of water. When water drops below 0 degrees Celsius (32 degrees Fahrenheit), it freezes and becomes ice.

Liquid – This is the moist substance that we drink and swim in.

Vapor – When water evaporates or exceeds 100°C and begins to boil, the water turns to a gaseous state called steam.

Water on Earth

Water is literally everywhere on Earth. About 70% of the Earth’s surface is covered with water. About 97% of the water on Earth is found in the oceans. This water is salt water and we cannot drink it. Another 2.4% of the water on Earth is frozen water in glaciers and ice caps at the poles. This leaves about 0.6% fresh water in rivers and lakes for us to drink.

Does Water have taste?

Pure water really has no taste. What you taste when you drink tap or bottled water are minerals and other substances that have dissolved in the water.

Is there Water on other Planets?

Yes, water is in many places in outer space. Indeed, the two elements of water, hydrogen and oxygen, are two of the most abundant elements in the universe. Much of the water we know on other planets is ice. Water ice can be found on the Moon, Mars, in the rings of Saturn, Pluto and on comets. Water vapor is also found in the atmospheres of other planets such as Mercury, Venus, Mars, and Jupiter.

Uses of Water

We use water not only for drinking. We use it in agriculture to grow food, in laundry to wash clothes and dishes, in firefighting to put out fires, and in hydroelectricity to generate energy from dams. These are just some of the ways we use water in our daily lives.

Interesting Facts about Water

Water is often used as the standard in scientific measurements such as temperature and volume.

Water that is safe to drink is called potable water.

Seventy percent of the human body is made up of water. Water dissolves more materials than any other liquid.

In the United States, the average person will use about 80 gallons of water per day. We use the most water by flushing the toilet.

Ice is lighter than water, allowing giant icebergs to float in the ocean.