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by fsckboy 1369 days ago
it's not just the coldness of the ice, salt dissolving in water actually decreases the temperature, it's an endothermic reaction.

the salt dissolving into the water brings the water down to 0... omg time for Farenheit to shine... brings the water down to 0F without freezing it (because of the lower equilibrium temp), which is -17.8C

(Farenheit uses this endothermic salted water temp as its definition of 0, I think because it was the coldest thing Dr. Farenheit knew how to produce in the lab)

2 comments

I understand Fahrenheit now.
I thought I did, but just thinking about what temperature is, i.e. the degree of hotness or coldness something is, so it relates to heat, which is the energy transferred from something hot to something cold, so it relates to energy, the more energy something has the hotter it is, the less energy the colder. So I am utterly confused now why wind cools or even can be cold, and wind chill should be a contradiction, and still stuffy air should be cold. Wind has more energy than still air, so wind should be hotter and still air cooler. Wind turbines deployed on a global scale should solve Global Warming even if no energy is generated, because they should slow down the energetic and hot wind, cooling the atmosphere and the planet with it.
The air around you is (usually) colder than your body. That means your body is transferring energy to the air. When the wind blows, convection causes you to transfer more energy to the air than you do when the wind doesn't blow. That increased transfer of heat away from you makes the wind seem colder/creates wind chill.
Unfortunately for this theory, brine freezes around -6f
You need something colder than brine to freeze brine. Fahrenheit didn't have that so the theory/story is still plausible.
That's why I said it was "part of the issue" - but once the salt has dissolved the system is kept at -5 for a period of time because inside of the ice cubes are < 5C
yes but as long as there is more undissolved salt (and when making ice cream you use a lot of salt), the melting ice will continue adding pure water to be chilled/saturated with salt.