Natural water cycle

The natural water cycle is the continuous movement of water around the world through the processes of evaporation, transpiration, condensation, precipitation, run-off, infiltration and percolation.

Natural water cycle process

What happens in the natural water cycle?

The natural water cycle uses physical processes to move water from the surface of the Earth to the atmosphere and back again.

Evaporation is when the sun shines on water and heats it, turning it into gas called water vapour which rises into the air.
Transpiration is when the sun warms people, plants and animals and they release water vapour into the air.
Condensation is when the water vapour in the air cools and turns back into a liquid, forming tiny water droplets in the sky.
Precipitation is when water droplets fall from the sky as rain, snow or hail.
Run-off is when water flows over the ground and into creeks, rivers and oceans.
Infiltration is when water falls on the ground and soaks into the soil.
Percolation is when water seeps deeper into tiny spaces in the soil and rock.

The natural water cycle moves water from the Earth to the atmosphere - and back again.

Water is continually moving through the natural water cycle.

Earth has exactly the same amount of water as it had thousands of years ago. This cycle is also called the hydrological cycle.

We modify and manage part of the natural water cycle to provide humans with water. This is called the urban water cycle.

Properties of water

Did you know?

Water is the most common substance found on Earth. It's the only substance found naturally in three forms – solid (as ice), liquid (as water) and gas (as water vapour).
Water is made up of tiny molecules. One water molecule, called H₂O, is made up of three atoms - two hydrogen atoms and an oxygen atom. These atoms stick together due to electrical energy.
Water is a solvent, which means it dissolves things. Wherever it travels, water carries chemicals, minerals and nutrients with it. This means water is more than what we can see.
Water can be tested to see if it is acidic, basic or neutral. We like our water around neutral so it doesn't corrode pipes and home appliances.

pH is measured in a scale from 1 (acid) to 14 (base) with 7 being neutral.

Water on Earth

Did you know?

The total amount of water on Earth is 1,386 million km³.
Water covers about three quarters of the Earth’s surface.
96% of the world’s water is saltwater.
3% is of the world’s water is freshwater, but most of it is frozen or not easy to get.
Less than one per cent of the world’s fresh water is useable.

Water cycle experiments

Have you ever wondered how water evaporates? Where clouds come from or where water goes after it rains? It’s all part of the water cycle.

Try these science experiments to see for yourself.

Make a cloud to see a part of the water cycle in action.
Explore how Water evaporation works and discover how water changes from liquid to gas.
Use a red cabbage to Make a pH indicator and test items around you home.
Make a simple water filter from things around the home and work out what makes a good filter.
Create your own mini earth with a Water cycle and terrarium and discover how water continuously recycles.

Terrarium with molecules, outline and sun

Create a mini Earth and water cycle.

Teacher resources

Stage 4 Geography Water Cycle Lesson Plan - How natural and human processes influence the distribution and availability of water as a resource.
Stage 4 Science Water Cycle Lesson Plan - How physical processes influence the flow and availability of water as a resource.