# Cooling rate of water

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Hey guys,

I have a physics design lab on factors that affect the cooling rate of water. I picked the concentration of salts in the water as my factor. I'm unable to find much on this, but my teacher reassured me its a proper factor.

So how would purity affect a substance's rate of cooling?

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The addition of salts generally causes only a small reduction in the specific heat capacity compared with that of pure water. So to observe the difference in the cooling rate, especially at low concentrations, you will have to make the measurements of mass, temperature and time very accurately, and control the environment carefully.

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Thanks a lot. So when you say there is a reduction in the specific heat capacity, you mean it will cool faster right? Sorry, this is my weakest link in physics :|

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Well, it does not affect the cooling rate of water per se, but the cooling rate of ice...

It lowers down the melting point of ice which takes ENERGY from the surroundings to transform into water which is causing the surroundings to become cool.

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Thanks a lot. So when you say there is a reduction in the specific heat capacity, you mean it will cool faster right? Sorry, this is my weakest link in physics :|

Yes, because of its reduced specific heat capacity, a given mass of salt solution will cool a little more rapidly than the same mass of pure water under identical conditions.

But then the idea is to investigate this by experiment, right?

Well, it does not affect the cooling rate of water per se, but the cooling rate of ice...

It lowers down the melting point of ice which takes ENERGY from the surroundings to transform into water which is causing the surroundings to become cool.

The addition of salt does of course lower the melting point of ice, but that is not the phenomenon that ananya.agrawal95 has been asked to investigate.

Edited by HiggsHunter
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I saw that later on. But I still stand behind the page I posted him to go onto. I think it has sth about what he asked though.

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Thanks a lot guys, my physics grade is safe

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