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. |
Justin |
Jun 10 2005, 01:30 PM
Post
#2
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Unregistered |
Before freezing:
Salt Water: was a lot lighter in color, milky color, you could see the salt, it smelt like the ocean. Fresh Water: looked like fresh water, just normal, clear While freezing: Salt Water: it was freezing more slowly, it took a while to freeze, the top froze first, as it froze the salt water had a thin layer of frozen and the fresh water had a thick layer of frozen, it didn't freeze--the top layer was soupy. Fresh Water: The top froze first and the sides and there was water in the middle, froze after about two hours, started to expand while it was freezing, middle froze first (????two different observations about what froze first) Frozen: Salt Water: On the top of the salt water, there were shards of ice. There was water still on the top of it. May have been bits of salt on the bottom, ice made some crystal formations, there was a big bubble in it. Fresh Water: Clear ice, some of the ice was over the top of the cup, it was level before it froze and then there was a big bubble, it started to crack Thawing: Salt Water: It thawed a lot quicker than the fresh water. The ice chunk had tons of bumps on it, on the sides there was a rim of water, it didn't quite freeze all the way, slushy. Fresh Water: It was clear to the end, the fresh water completely unfroze first (???seemed wierd), the water that bubbled on the top feel off. It took over four hours to unfreeze. I noticed before freezing there was salt on the bottom, but after freezing there wasn't any salt on the bottom, did the ice crush the salt? Why did some peoples' sides freeze first, and others the middle froze first? Why did the salt water take longer to freeze? Why were their bubbles? How come the salt makes the ice cloudy? Why were there bumps on the side of the ice? Why did the freshwater ice crack? Does it matter when thawing if you have different sized containers--will they thaw at the same rate? Does it matter the material the container is made of? If you had a glass of fresh and salt water at the same temperature, and you put an ice cube in each, would the salt water melt the ice cube faster? Does it matter what temperature the water is when you put it in the freezer? Does the temperature the room is at when you are trying to thaw them make a difference? |
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