water cycle= Ο κύκλος του νερού

THE WATER CYCLE

Water is used everywhere and for almost everything – PRIVATE USE

…so humans have an enormous waste of water every day!

- INDUSTRIAL / PUBLIC USEPaper production

Colouringclothes

Food production

Agriculture

INDUSTRIAL – PUBLIC USE

But where does it go and come from?

THE WATER CYCLE

• The water cycle describes the continuous movement of water on, above and below the surface of the Earth.

• The water moves by the processes of evaporation, condensation, precipitation and collection. Doing this the water goes through different phases: liquid, solid (ice), and gas (vapor).

1. Evaporation

• Evaporation is when the sun heats up water in rivers, lakes or the ocean and turns it into vapor or steam

• The water vapor or steam leaves the river, lake or ocean and goes into the air

Transpiration

• Plants put down roots into the soil to draw water and nutrients up into the stems and leaves.

• The other way that water gets into the air is through transpiration, which is water evaporation through plants. They provide a lot of water to the water cycle.

2. Condensation• Water vapor in the air gets cold and changes

back into liquid, forming clouds. This is called condensation.

• Condensation is the opposite of evaporation.

• Condensation also occurs at ground level, the fog develops when the air that has a relatively high humidity content comes in contact with a colder surface, often the Earth's surface, and cools to the dew point.

Sublimation • Sublimation is a process where ice directly

converts into water vapors without converting into liquid water.

• The main sources of water from sublimation is the ice from the North Pole and the South Pole.

• Is a slower process than evaporation

3. Precipitation

• Precipitation occurs when so much water has condensed that the air cannot hold it anymore. 

• The clouds get heavy and water falls back to the earth in the form of rain, hail, freezing rain or snow.

4. Collection

• When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. 

Infiltration

• Some of the water that precipitates does not runoff into the rivers and is absorbed by the plants. It moves deep into the soil and collect in the oceans, lakes or rivers where the cycle starts all over again.

• The water goes into the ground and increases the level of ground water. It is called pure water and is drinkable.

• Water is not magically appearing or disappearing, it is always the same

Because of the WATER CYCLE the water we use today is the same water that already existed millions of years ago!

So water does not have an age!

How much water is on the earth?

• It's approximately 326 million cubic miles

• About 72 percent of Earth is covered in water, but 97 percent of that is salty ocean water and not suitable for drinking.

We can divide the amount of water…

Who has access to clean water?

If all the water of the surface of the earth would be in a bubble, it would

have this size:

• And all the water of the Earth compare to all the water we can drink would look like this…

We are not the only planet with water…

• Water is present as vapor in:The atmosphere of Mars

The atmosphere of Mercury

The atmosphere of Jupiter

The atmosphere of Saturn…

…among others!

THANK YOU