AT what temperature does water have its smallest volume, and thus its greatest density?
A substance exists in its smallest and most dense form when it is in a solid state.
A substance exists in its smallest and most dense form when it is in a solid state, as its molecules are as closely packed together as possible. Ignoring the influence of pressure on a state, then the temperature at which water becomes solid (freezing point) is the temperature at which water assumes its most dense shape. With water however, solid form is NOT the smallest volume possible. Water assumes a larger volume when solid than in liquid form, this is due to the lowest energy arrangement of molecules and bonding. It’s a bit of a trick question really!