How does de-icer work?

De-icers work by lowering the freezing point of water, which
causes it to turn back from ice into liquid water. Usually
this is due to the addition of a chemical compound such
as sodium chloride (often called
rock salt) or calcium chloride. Most
de-icers that you can buy off the shop
shelf aren’t designed to melt every
piece of ice they come into contact
with – they simply break the bond
between the ice and the surface
allowing for easier manual removal
of the ice.