What is water?

 

What is water made of?

Water is made of molecules. Each molecule has two hydrogen (H) atoms and one oxygen (O) atom.

This means that water’s chemical formula is H2O.

Water molecule

 

What makes water special?

Water is the most abundant substance on Earth’s surface. It covers more than 70% of the planet in oceans, rivers, lakes and glaciers.

Water has some unique properties:

 

• it can be solid, liquid or gas at normal temperatures on Earth.
• it is most dense at 4°C. Below this temperature, ice floats on liquid water.
• it dissolves many substances, such as salts in the sea and proteins in living things.
• it has a high surface tension, which lets some small insects walk on its surface.
• The image shows water in its solid and liquid states and how materials can be solid, liquid or gas at different temperatures.

 

 

Why is water important?

Water is vital to all living things on Earth. Plants use water in photosynthesis to make their food.

About 60% of the human body is water and it does many things, such as:

 

• dissolving important nutrients in the blood and taking them to cells.
• keeping our body temperature stable.
• dissolving waste substances and removing them from the body in urine, faeces and sweat.
• protecting tissues, joints and the spinal cord.

 

Humans need to drink enough water to replace what we lose though sweat, urine, and faeces.

 

Summary:

 

• Water is made of two elements: hydrogen and oxygen.
• Water has many unique properties.
• Water is essential to all living things on Earth.