CIRCIN · PREVIEW Why salt actually melts ice 0:47 · watch in the Circin app

Why salt actually melts ice

It is not heat, it is chemistry. Freezing-point depression in 40 seconds.

Discussion · 312

📌 Pinned@mayachenchem3h · ♥ 1.2K
Quick note: this only works down to about -9C (18F). Below that road crews switch to a different salt. Keeping this pinned.
@younow · ♥ 3
Saving this for my chem final, thank you!
Question@confused_casey2h · ♥ 37
At 0:42 — why does the road get COLDER while the ice is melting? That feels backwards.
@mayachenchem1h
Great catch — melting takes energy, and the salt water pulls that energy from itself and the road. So the slush can drop below 0°C. Backwards-feeling, but right.
@frostbite_ken2h · ♥ 88
Wait, so is this why they also throw sand down? or is sand just for grip?
@mayachenchem2h
Sand is only for traction, no melting involved. Great question.
@skeptic_sam1h · ♥ 41
Isn't this technically not melting? The ice still needs energy from somewhere.
@mayachenchem1h
Right, it lowers the freezing point and the melting pulls heat from the surroundings, which is why the road gets colder. Good catch.
@nina.k44m · ♥ 15
finally an explanation that isn't 20 minutes long

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