If you add other substances to water, such as sugar or salt, the temperature drops below 32 degrees before ice begins to form. The new freezing point depends on the added substance and how much you mix with water, and this is why cities put salt on the roads in some states to remove ice and snow in the winter.
At What Temperature Does Water Freeze? The answer is far more complicated than it first appears—water doesn’t always turn to ice at 32 degrees Fahrenheit.
Thus slow-freezing ice rejects impurities including air, minerals, and salts, and pushes them out of the way. This is why the last part of the ice to freeze is where any trapped air and impurities are. Most ice cubes are cloudy in the middle because the water is freezing on all four sides of the container; outside-in.
The time it takes for water to freeze varies from several hours to a month, depending on the volume of water, its temperature and the temperature of the surrounding air. Water freezes when it reaches 32 degrees Fahrenheit, but the time it takes for liquid particles to reach that point differs.
Point out that when water freezes, the water molecules have slowed down enough that their attractions arrange them into fixed positions. Water molecules freeze in a hexagonal pattern and the molecules are further apart than they were in liquid water. Note: The molecules in ice would be vibrating. The vibrations are not shown here but are shown ...
Water expands as it freezes, so if you use a mug or Nalgene bottle to freeze water in, then it is possible that it will crack the container. A metal cup, ice cube tray, or a plastic disposable water bottle are all good options. If you boil water before freezing it, the ice will come out crystal clear instead of cloudy.
The freezing point describes the liquid to solid transition while the melting point is the temperature at which water goes from a solid (ice) to liquid water. In theory, the two temperatures would be the same, but liquids can be supercooled beyond their freezing points so that they don't solidify until well below freezing point.
When water freezes, the molecules slow down and assume a fixed position, although not quite in the way that one might think. Water is made of molecules with two hydrogen atoms and an oxygen atom, but those molecules don't just stop moving as units.
This occurs in completely pure water and usually in a very smooth container. So water turning into ice is not as straight forward as just getting cold. Other things also affect water freezing, including dissolved solids, water density, pressure and movement (such as currents).