Atmosphere
Gases that surround a planet, like the air that surrounds Earth.
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Natural water cycle
Water is constantly moving around
Did you know that all the water on Earth is all that we have? It's constantly moving around in a natural cycle. Some water is easy to see in our rivers and oceans, but some water is underground or in the atmosphere.
Natural water cycle processes
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.
What happens in the natural water cycle?
The natural water cycle uses physical processes to continually move water from the surface of the Earth to the atmosphere and back again. This cycle is also called the hydrological cycle.
- 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.
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 3 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 3 atoms – 2 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.
Water on Earth
Did you know?
- Earth has exactly the same amount of water as it had thousands of years ago.
- The total amount of water on Earth is 1,386 million cubic kilometres.
- 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 1% 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 and 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 your home.
- Make a simple water filter from things around the home and work out what makes a good filter.
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.
Evaporation Practical Investigation Learn how we can use evaporation to separate water.
Glossary - Find definititions to key words and industry terms.