1. The Water Cycle
Where does the water come from, where does it go, and what does it do when it gets there?

2. The Water Cycle
When Sir Isaac Newton tossed an apple in the air, he observed, “What goes up, must come down.” The same could be said for the water cycle. We could also add, “What comes down, must go up.”

3. The Water Cycle
The Water Cycle has no beginning and no end. Water has been moving up, down, and all over our world since we have had water on our planet.

4. Where did we get all of this water?

5. Where did we get all of this water?
The water on our planet has been here for a very long time. There are several theories on where it came from.

6. Where did we get all of this water?
Some say that it came from the volcanic activity back when our planet first formed. At this point, our planet is covered in lakes of lava and is full of volcanoes.

7. Where did we get all of this water?
When volcanoes erupt, they release many different types of gases, two of which are hydrogen and oxygen.

8. Where did we get all of this water?
When the oxygen released from the volcano combined with the hydrogen in the air, it made water.

9. Where did we get all of this water?
When two molecules of hydrogen bond with one molecule of oxygen, it forms a single molecule of water. That is why water is sometimes referred to as H2O.

10. The other theory is that the water came from outer space
The other theory is that the water came from outer space. Some scientists think that a comet, or several comets, crashed into our planet when it was very young.

11. The ice from the comets melted and in time formed the oceans, lakes, and rivers.

12. THIS JUST IN!
In June of 2014, it was announced that scientists have discovered evidence of a vast reservoir of water hiding up to 400 miles beneath the surface.

13. THIS JUST IN!
The water is trapped in a blue mineral called ringwoodite that sits in the mantle, a hot, rocky layer between the Earth's crust and outer core. That means the water is not the familiar liquid, vapor or ice, but a fourth, mineral form.

14. How much water do we have?

15. How much water do we have?
We have an estimated 332,500,000 cubic square miles of water on our planet.
Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp

16. How much water do we have?
If I were to build a box. Making it one mile tall, one mile wide, and one mile long, and filled it with water, that would be one cubic mile of water.

17. How much water do we have?
Now build 332,500,000 more boxes and you have our world’s water supply. But you can’t drink it all?

18. How much water do we have?
That tiny water bubble has a diameter of about 860 miles. Meaning from the ground to the top is 860 miles as well.
What would it look like if we took 332,500,000 square miles of water and put it all in one place?

19. How much water do we have?
Of the 332,500,000 cubic square miles of water, only 2 ½ percent is drinkable.
Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp

20. How much water do we have?
There is an estimated 8,400,000 cubic square miles of fresh drinking water on our planet.
Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp

21. How much water do we have?
An estimated 75% of the fresh water on our planet is frozen at the north and south poles, in the form of glaciers.

22. How much water do we have?
That is to say that 6,300,000 cubic square miles of fresh water is frozen at the poles.

23. How much water do we have?
That leaves approximately 2,100,000 cubic square miles of fresh potable drinking water on our planet, for all living things to drink.

24. If we were to put all the fresh water on the planet next to our other water bubble, it would look like this.

25. What is the water cycle?

26. Condensation Precipitation Evaporation Run-Off
At its core, the water cycle has four steps:

27. Evaporation Transportation
Condensation
Precipitation
Evaporation Transportation
Run Off
Evaporation occurs when the sun shines on our rivers, lakes, and oceans, causing the water to evaporate and turn into vapor.

28. Evaporation
Evaporation means when water is turned into water vapor, or when a liquid is turned into a gas.

29. Condensation Evaporation
The water vapor begins to rise up through the atmosphere. As it gets higher in the air, the air cools and the water vapor begins to condense.

30. Condensation
When a gas condenses, it turns from its gaseous form to a liquid form. In this case, from water vapor into tiny droplets of water.

31. What is the water cycle?
These droplets then form clouds in the sky. As the air gets cooler, the droplets get bigger, until the wind can no longer hold them up. They begin to fall to the ground.

32. Condensation Precipitation
When water falls to the ground, it is called precipitation.

33. We commonly think only of rain as precipitation, but snow, sleet, hail, and even fog are all forms of precipitation.

34. Precipitation Saturation or Run Off
When the rain hits the ground, the ground begins to absorb the water. This is known as saturation.

35. Saturation refers to how much water is being held in the ground.

36. Once the ground is totally saturated and can not hold any more water, it will begin to pool into puddles.

37. The water begins to run off into rivers and streams
The water begins to run off into rivers and streams. Rivers and streams flow into larger bodies of water such as lakes and oceans.

38. Once precipitation stops and the clouds clear, the sun comes out, and begins to evaporate the water on the ground.

39. And so the water cycle renews. It has no beginning and no end
And so the water cycle renews. It has no beginning and no end. It simply is...