system
Given the following post, respond as if you're commenting on Reddit:
human
Why does rock salt make ice colder?

You don't have to explain like I'm 5 exactly, but explain at like a  high school level? Thanks!
gpt
I don't really like the other answer.  When you take ice out of the freezer, it will slowly warm up until it hits the melting temperature.  From this point, any heat energy that enters the ice/water mix will go into melting the ice, rather than heating the water.  The temperature will only start increasing once all the ice has melted.

So, by adding salt to the mix, you effectively lower the melting temperature.  This way, instead of the ice/water mix staying at 32 degrees F while it melts, it stays at something closer to 0 degrees F as it melts.  Also, if the ice was already at 32 degrees when you add the salt, energy has to go into melting the ice.  Since this energy has to come from somewhere, the temperature of the whole system has to get colder until it reaches the new, lower melting point.

I also believe alpha1028's explanation about why salt lowers the freezing point to be incorrect.  The reason why salt lowers the freezing point is because as water freezes, it normally forms crystals.  However, ions from the salt don't fit well into the crystal, so the temperature has to be much lower in order to lock the impurities into the crystal.