The freezing point of a liquid depends on the water content of the liquid, so milk freezes faster than liquids with lower water content. Milk is available with varying amounts of water contents which are identified by whole milk, 2 percent milk, 1 percent milk and skim milk.
The freezing point of any liquid depends upon the molecules present in the liquid. The molecules are constantly moving but, as the temperature drops, the molecules have a harder time moving around, so they freeze. Water freezes at about 32 degrees Fahrenheit, but the other molecules will affect the freezing rate. A 1 percent milk sample will freeze faster than a whole milk sample because of the increased water content.