The Water Cycle

1. The Water Cycle

2. Water never leaves the Earth. All of it is constantly being cycled through the atmosphere, ocean, and land. This process, known as the water cycle is driven by energy from the sun. The water cycle is crucial to the existence of life on our planet.

4. During part of the water cycle, the sun heats up liquid water and changes it to a gas by the process of evaporation.Water that evaporates from Earth’s oceans, lakes, rivers, and moist soil rises up into the atmosphere.

6. The Water Cycle Most evaporation takes place from the oceans since there is more water there than anywhere else on Earth. Why is rainwater not salty, if most of it originated from water evaporated from salty oceans?

7. First, let’s look at why the ocean’s are salty to begin with. Ocean water is salty because it has minerals that wash into the ocean from land and dissolve. When weathering creates sediment from rocks, some of the minerals that they were made from get washed down rivers and into the oceans. Over billions of years the sodium chloride (NaCl-salt) that was in the rocks on land dissolved in the oceans and made them salty. But when water evaporates from the ocean, the salt stays behind. Remember when we let the water evaporate from the beaker with saltwater in it and the salt was left in the bottom?

8. Now, try to answer this question. Tropical seas have a high rate of evaporation. Because of this, the water in tropical seas will have higher: A. wave crests. B. amounts of algae. C. daily temperatures. D. salt concentrations.

9. Now, let’s try another question. There are many bodies of water in or next to Georgia, including Lake Blackshear and the Atlantic Ocean. What is MOST LIKELY a difference between the water in Lake Blackshear and the water in the Atlantic Ocean? A. The water in Lake Blackshear is always much colder than the water in the Atlantic Ocean. B. The water in the Atlantic Ocean is part of the water cycle, but the water in Lake Blackshear is not. C. The water in Lake Blackshear comes from rivers, while the water in the Atlantic Ocean comes from rain. D. The water in the Atlantic Ocean contains more dissolved minerals than the water in Lake Blackshear. In other words the water in the ocean is _______________ and lake water is not.

10. Here’s another question. When ice forms in the oceans, what happens to the water found directly underneath the newly formed ice?

11. Why don’t the oceans just keep getting saltier and saltier as time goes by? • The oceans are just as salty now as they were a million years ago and longer. • If you took a thousand pounds of seawater and could pull out all the salt, you would have 35 pounds of salt. That’s measured as 35 parts per thousand or 35 o/oo. (demo) • Even though the salt is left in the oceans when water is evaporated from them, and weathering and erosion keep putting more salt in, the oceans don’t get any saltier. • This is because about the same amount of freshwater flowing in from rivers and falling as precipitation is almost exactly the same as the amount of water that is evaporating from the oceans and about the same tonnage of salt from the ocean water is deposited as sediment on the ocean bottom as the amount of new salt coming in from weathering and erosion of rocks. • This is part of the balance created by the water cycle. • If not for this balance, the oceans would be so salty by now that most of the marine life could not exist.

12. From where does the water evaporate that gives us our rain in Columbus?

13. Transpiration (sometimes called evapotranspiration) is similar to evaporation

14. The process of evaporation from plants is called transpiration. (In other words, it’s like plants sweating.)

15. Condensation is the step in the water cycle that takes place between evaporation and precipitation.

16. As water (in the form of invisible gas) rises higher in the atmosphere, it starts to cool and become a liquid again. The water droplets then clump together around tiny dust particles. This process is called condensation. When a large amount of water vapor condenses, it results in the formation of clouds.Clouds are actually liquid water and dust particles that aren’t heavy enough yet to fall back to Earth.

17. Precipitation returns the water in clouds back to Earth. Remember, most precipitation over land comes from water evaporated from the oceans.

18. When the water in the clouds gets too heavy, gravity is the force that causes the water to fall back to the earth. This is called precipitation. Precipitation can take different forms like rain, snow, sleet, or hail.

19. Runoff is rainwater that moves across the surface and flows into lakes, rivers, streams, and the ocean

20. When rain falls on the land, some of the water is absorbed into the ground forming pockets of water called groundwater. Soil is porous, that is it has tiny spaces between the pieces of rock and other material from which it is made. When a substance is porous and therefore allows water to be absorbed it is said to be permeable.Let’s list some other things besides soil that are permeable. Most groundwater eventually returns to the ocean. Other precipitation runs directly into streams or rivers. Water that collects in rivers, streams, and oceans is called runoff.

21. http://perso.orange.fr/prof.danglais/animations/watercycle/watercycle.htmhttp://perso.orange.fr/prof.danglais/animations/watercycle/watercycle.htm