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> Ocean Water and Fresh Water
Amy_Clapp
post Jun 5 2005, 07:00 PM
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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.
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Jesse
post Jun 8 2005, 11:09 PM
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I think that the cup with salt water in it will freeze slower because it has salt in it. The salt slowes down the rate of freezing. This is kind of like in Montreal as the salt water flows into the river which is fresh water the salt water sinks to the bottom. wink.gif
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Bailey and friends
post Jun 9 2005, 02:18 PM
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I think the salt water will freeze faster than the fresh water because it has more stuff in it.

We observed the salt water didn't fully freeze. There were air bubbles on the bottom. There was a little water moving around in the salt water glass after it froze. I saw bits of salt in the salt water glass. When I first checked it the top and bottom were frozen. The fresh water glass cracked, the salt water one didn't.
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Jesse
post Jun 9 2005, 09:29 PM
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biggrin.gif During the lab I noticed that the bottom of the ocean water cup didn't freeze like the rest of the cup. I also noticed that the fresh water had already completely frozen at 7:00 this morning and the ocean water haden't at the bottom. The ocean water hasn't canged at all since I last checked it. The bottom of the ocean water cup has quite a few bubbles stuck in the bottom of it. I am going to see if anything changes from now till tomorrow morning.
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Class
post Jun 10 2005, 12:32 PM
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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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Justin
post Jun 10 2005, 01:30 PM
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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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Guest
post Nov 8 2005, 11:44 PM
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Im doing this for my science fair project.

Do i have to get sea water?, Or could I just pour salt into a cup of water.

Thx

asain pride
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Guest
post Nov 8 2005, 11:49 PM
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I forgot to add, the salt will freeze slower because salt "depresses" the freezing point.
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Guest
post Nov 8 2005, 11:50 PM
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I forgot to add, the salt will freeze slower because salt "depresses" the freezing point.

Asain pride

P.S. If i had a post before this, delete it.
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aj
post Jan 7 2006, 02:36 AM
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im a lair!

Asain pride

P.S. If i had a post before this, delete it.
*

[/quote]
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Guest
post Jan 11 2006, 02:35 AM
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does salt water freeze
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Guest
post Feb 5 2006, 11:12 PM
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QUOTE(Justin @ Jun 10 2005, 01:30 PM)
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?
*


cool.gif dry.gif
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Simone
post Feb 19 2006, 06:56 PM
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Im doing my science project on why salt water freezes slower than fresh water. I need to do a research paper explaining why. Can someone please explain to me what to write in my paper?
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Amy_Clapp
post Feb 19 2006, 10:23 PM
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HI Simone,
Hopefully this experiment will help out with your project a bit. I will give you a hint about your paper--you should research what salt does to the water molecules. This might help you figure out why the salt water didn't freeze as quickly. Let me know how it goes!

Amy
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Simone
post Feb 21 2006, 09:35 PM
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is it that salt lowers the freezing point of water?
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Amanda
post Apr 5 2006, 04:05 PM
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does anyone know how to make salt water into fresh water
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Amanda
post Apr 5 2006, 04:07 PM
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im doing a class project and i have no idea what to do is there even anyone on here right now
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Guest
post May 4 2006, 09:46 PM
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QUOTE(Simone @ Feb 21 2006, 09:35 PM) *

is it that salt lowers the freezing point of water?
i have the same question
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Laura
post Aug 23 2006, 08:05 AM
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QUOTE(Amanda @ Apr 5 2006, 04:05 PM) *

does anyone know how to make salt water into fresh water

yes u boil it and catch the steam let the steam cool witch will then turn into vapour, after that you have fresh water didi u noe that 70% of the worlds fresh water is in Antarctica
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Guest
post Sep 1 2006, 03:12 PM
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QUOTE(Laura @ Aug 23 2006, 08:05 AM) *

yes u boil it and catch the steam let the steam cool witch will then turn into vapour, after that you have fresh water didi u noe that 70% of the worlds fresh water is in Antarctica

i dont know do you
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