Answer. Water exists in three distinct phases at something called the triple point. ... Molecules in the liquid phase can loose a bit of energy and solidify whilst solid water (ice) can gain some energy and melt. ... At a certain energy molecules will have enough energy to evaporate, even if the water temperature is 0 degrees C. read more
For water at 0 degrees Celsius, the vapour pressure is about 613.283 N/m [math]^2[/math] or 0.613283 bar. So if you lower the pressure below this value, the liquid water at 0 degrees will turn to vapuor state. So water at 0 degrees C can exist as solid, liquid or gas, depending on the conditions. Edit - Here is a graph to visualise it. read more
Water exists in three distinct phases at something called the triple point. Zero degrees celsius is defined by the triple point of water which is 273.16K at 611.2 Pa. At this temperature water is in the process of changing from a solid state into the liquid phase or visa versa. read more