However, even with this definition it is not clear whether "freezing" refers to the point at which water forms a visible surface layer of ice; the point at which the entire volume of water becomes a solid block of ice; or when the water reaches 0 °C (32 °F).
Tačiau net ir su šio apibrėžimu neaišku, ar "užšala" reiškia momentą, kuomet ant vandens paviršiaus formuojasi matomas ledo sluoksnis; momentą, kuomet visas vandens tūris tampa kietu ledo luitu; arba kuomet vanduo pasiekia 0 °C (32 °F).