1. The Water Cycle
Science 8

2. The amount of water on Earth is finite (which means that there is a limited amount).
All of the water present at the beginning of time is still present now!

3. All water on Earth is constantly
moving.
The natural water cycle, also known as the Hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth.

4. The water cycle is self-renewing and constant.
The Sun provides the energy to power the water cycle.
Water is always changing states between liquid, vapor (gas), and ice.
These processes happen in the blink of an eye and over millions of years.

6. The Water Cycle Process
The water cycle collects, purifies, and redistributes the Earth’s water.
The sun heats up the bodies of
water it is shining on.
The heat causes some of the water to change from a liquid state to a gaseous state, this is called evaporation.

7. Evaporation Only pure water evaporates.
Fact →This is the reason why the ocean stays salty! Pure water evaporates leaving the salt behind.
Water also evaporates from the upper layer of soil and from plants. Evaporation from plants is called transpiration (it like plants sweating!)

8. Condensation
As evaporated water rises into the sky, temperatures cool and it collects around particles of pollution and dust to form larger droplets.
The process where water vapour (gas) in the air turns into liquid water is condensation.
Condensation helps in the formation of clouds.

9. Precipitation
When the water forming clouds becomes too heavy, water droplets fall to the ground in the many forms of precipitation (rain, sleet, snow).

10. Runoff
Excessive rain or snowmelt can produce overland flow to creeks and ditches.
Runoff is visible flow of water in rivers, creeks and lakes as the water stored in the basin drains out.

11. Percolation
Some of the precipitation and snow melts and moves downwards, percolates (filters) or infiltrates through cracks, joints and pores in soil and rocks until it reaches the water table where it becomes groundwater.

12. Groundwater Subterranean water is held in cracks and pore spaces.
Depending on the geology, the groundwater can flow to support streams. It can also be tapped by wells.
Some groundwater is very old and may have been there for thousands of years.