Question

how does salt affect the way water freezes

Answer 1

Salt DECREASES the freezing point of water, meaning it melts a lot easier. In fact almost any other substance that you put into water will decrease the freezing/melting point since it disrupts the intermolecular forces (mostly hyrdogen bonds) that keep the water in solid state. Adding Na Cl or any common salt is a cheap way to make these intermolecular forces weaker and so requires a lower temperature to melt. Water freezes (and melts) at zero degrees, so know it will melt at a LOWER temperature, just like salting the road in the winter.