You mean adding salt?
8:59am by
Jennyhirsch
Yes I meant adding salt.
9:37am by
vickiwaffles
Breaking out my ancient thermodynamics college course learnings, adding salt allows the water to freeze at a lower temperature in the first place. When it comes to adding salt to a bag of already frozen ice, I assume the subsequent melting will...
9:54am by
JJT (staff)
..lowers the melting & freezing points of the ice and effectively absorbs more heat from its surroundings(?)
9:57am by
JJT (staff)
Ummmm does that mean yes @JJT add salt?
11:37am by
popupcamper
@pop I have the same question :)
11:49am by
VikeQueen
Yes. Add salt to ice to keep it from melting as fast.
11:55am by
evamarie320
Ohhhhhh that's why we added rock salt to the crank ice cream maker when I was growing up. But wait why do they salt the roads and sidewalks when we get a freeze?
12:44pm by
popupcamper
Salt is used on icy roads to lower the freezing point of water, preventing ice from forming or causing existing ice to melt
12:56pm by
Elaine5715
Yes to everything above.
1:17pm by
Jennyhirsch
Okay so ELI5. How can it help ice melt on roads, but keep ice frozen in a beverage cooler? Aren't those opposite outcomes?
4:01pm by
popupcamper
Just went down a YouTube rabbit hole. Adding salt does melt the ice. On the road and in a baggie. But it also makes it colder. So while the baggie of salted ice will melt faster, it'll also be colder. Same thing with the roads.
4:15pm by
popupcamper
So if the goal is to keep ice solid, don't add salt. If the goal is to keep something colder, add ice to the salt. If the goal is to keep water from icing in the first place, add salt.
4:17pm by
popupcamper
I should add I'll begin adding salt to my coolers at the beach. I had no idea!
4:18pm by
popupcamper
Okay wait. If it gets colder, but it's melted. Will it stay cold as long? I need to do an experiment. Hold the phone.
4:28pm by
popupcamper
So, what does salt do when it's on the rim of my margarita glass? Oh, yes -- makes me drink it faster and order another one. Who said science is dead?
4:30pm by
gmcc
@popupcamper said it much clearer than I did. I went too much into the #nerdzone. :D
5:21pm by
JJT (staff)
@gmcc I think you need several rounds of physical trials to prove your hypothesis.
5:22pm by
JJT (staff)
An hour into the experiment: method - 74 g ice in four identical highball glasses. I added 5 g Redmond natural salt into 2 glasses and stirred. Put 2 glasses - 1 salt 1 none in a 43 F fridge. Left 2 glasses - 1 salt 1 none on the counter in a 77 F kitchen
6:08pm by
popupcamper
After 5 min: counter ice salted is 7.4 F colder; fridge salted is 12.2 F colder (22.8 versus 35.0)
After 20 min: counter ice salted is 6.5 F colder; fridge salted is 13 F colder (19.6 vs 32.72)
6:10pm by
popupcamper
After an hour: counter ice salted is HOTTER by 4.9 F (both are almost completely liquid, but non salted appears to have a bit more ice); fridge salted is 11.34 F colder (21.7 vs 33.)
6:13pm by
popupcamper
I'll do my next measurements before bed tonight. Then one more time in the am.
6:13pm by
popupcamper
This isn't the best experiment as I'm not measuring the temp of the fridge with ice versus salted ice which is what we're trying to test but since I don't own a beverage cooler hopefully this is the next best thing.
6:16pm by
popupcamper
Next experiment: if you add more salt do you get colder glasses.
6:25pm by
popupcamper
I'm very invested in this experiment now :) also , I want a margarita
6:43pm by
VikeQueen
Ha ha. Nerds!
6:47pm by
JackOfAll
The phase change also takes energy. So if you start out with ice, it 'uses' energy to get to melting point, then additional energy to melt.
6:47pm by
moondance07
So @moon, is it making the fridge hotter to make the ice colder? DS has a dorm fridge. I bet I can get him to do ths experiment. He has two weeks before school starts.
6:56pm by
popupcamper
Alright DS is on board. He's asking if anyone knows what temps the beverage coolers get to so he can best replicate. Anyone know?
7:21pm by
popupcamper
Not an official time as I'm not writing it down but 2.5 hours in the salted ice in the fridge is still significantly colder. Salted ice on the counter is warmer. Both counter glasses are totally water now. Fridge salted ice is probably have melted...
7:39pm by
popupcamper
Non salted ice is mostly still ice. Very little water, my guess is a teaspoon versus 2-3 tbsp.
7:40pm by
popupcamper
In my experiment, I just woke up after being passed out for a couple of hours.
8:09pm by
gmcc