Ocean Water and Fresh Water |
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Ocean Water and Fresh Water |
Amy_Clapp |
Jun 5 2005, 07:00 PM
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#1
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TREC Teacher Group: TREC Team Posts: 84 Joined: 27-April 05 Member No.: 6 |
So, a big part of the PARTNERS Project, is about analyzing the water so that the scientists can try and find out where the water goes when it travels from the rivers into the Arctic Ocean. The Arctic Ocean is one of the saltiest oceans but with all the fresh water that is traveling from the rivers to the ocean it is getting less and less salty. In this experiment you will try freezing two different kinds of water
Question: How does salt in water affect the freezing of water? What is your prediction? (I think... (describe what you think will happen) because..(explain why you think what will happen will happen). Procedure: 1.) Get two large glasses and label them with tape--label one sea water and the other fresh water. 2.) In each glass pour 12 ounzes of water. 3.) In the sea water glass put two and a half teaspoons of salt. This glass is similar to the salt content of the oceans. 4.) Make some observations about the differences between the salt water glass and the fresh water glass. 5.) Put both glasses in the freezer and check on them every few hours, making observations when you check on them. 6.) After they have been in the freezer overnight, look at the glasses again and complete another set of observations--be sure to observe the bottom of the glasses too!!. 7.) Continue to make observations as each of the waters begin to melt. One of the ways that science advances is by scientists sharing their results from experiments with each other and talking about what they are thinking and/or what they found out. So, what did you think would happen when you put the fresh and salt water in the freezer? What did happen? What were your observations? Why do you think what happened happened? What is great about this website is that we can easily share and discuss what we found out. Simply click on the "ADD REPLY" button on the top of this page on the right hand corner and share your observations and questions you may have. Once we get some ideas going, we can discuss new questions and experiments so that we can learn more about how salt water acts differently than fresh water and why. |
Class |
Jun 10 2005, 12:32 PM
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#2
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Unregistered |
Here are our observations:
Before freezing: The salt water was foggy and misty, there was salt on the bottom and it smelt salty. The fresh water was clear During freezing: The salt water got slushy and didn't get a chance to freeze--it made thin ice. The fresh water ice was lifting up and it had little cracks. When it was frozen: The salt water took longer, there were bubbles trapped on the bottom, the bottom didn't freeze, couldn't see through it, it was not as solid. The fresh water ice looked like a big ice cube, the ice expanded out, it froze faster and the ice level was higher than the water level before freezing. When it was melting: The salt water broke up, it thawed faster, it hollowed out a little bit, it melted in the same shape as the cobe, and there was salt on the bottom even though it didn't freeze. The fresh water melted slower even though it was in the same place, after it started melting the ice block got cracky and tough, it looked like an apple core, and it broke in half. Questions that the class still has: Why was the bottom of the sea ice not frozen? Why does salt melt ice? How come salt water looked criss-crossed when frozen and the fresh water didn't? Why did salt water have traps when it was frozen? Why does it tke longer for fresh water ice to melt than salt water? How much more dense is the real ocean compared to our cup? Why did the salt water hollow out when it was melting? Would another liquid act the same way? |
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