Ik that water’s volume decreases from 4°C to freezing, but what about ice? What happens if it’s decreased from 0°C? Does the volume increase or decrease?
In: Chemistry
Doesn’t waters Volume increase when frozen?
> What happens if it’s decreased from 0°C?
It contracts. Like almost every other solid out there
> Does the volume increase or decrease?
Decrease.
Ice has a positive thermal expansion coefficient, so it expands when heated and contracts when cooled – like most materials.
It contracts during the liquid phase change which is unusual, but otherwise is a pretty standard material.
It is not the ice that behaves weirdly. It’s cold water (between 4C & 0C) that has a strange behaviour.
Above 4C: water will behave as a “normal” liquid. This is, expanding when heated and contracting when cooled. This is because heat is equal to energy. By introducing energy into the system molecules will move faster, thus need to be further away from each other. Removing the energy will allow to keep molecules close together.
Below 0C (ice): will keep contracting as you cool it down (remove energy). But volume change is not that significative in comparison to liquid or gaseous water.
Between 0C & 4C: water will behave in a “abnormal” way. This is contracting when cooled and expanding when heated. Why? Water molecules are held together by hydrogen bonds. You can imagine this like molecules hugging each other. When there is enough energy (above 4C ) molecules are always interchanging hugs with each other and can be randomly arranged. As you cool it down, molecules will start to be fixed to each other. There will less and less random arrangement, thus grouped molecules will occupy more space.
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