Why does steam create pressure, yet ice expands to create water spikes?

Question

This always confuses me, is it cold that expands and heat contracts?

or the other way around, cold contracts & heat expands?

or as steam & ice spikes suggest, both steam & ice spikes expand? (free energy?)

In: Chemistry

Answer 1

In general, heat expands and cold contracts. Water is unusual in that, as it forms into solid ice crystals, that crystalline structure results in it expanding rather then contracting. But this is the only point at which water is an exception. Starting with temperatures just a little bit above freezing and hotter, liquid and gaseous water expand in heat and contract in cold. The density of ice also continues to contract as it grows colder.