• Question: what happens when water gets really hot then gets really cold

    Asked by anon-185151 to William, Rebecca, Martyna, Callum, Alice, Adam on 8 Nov 2018.
    • Photo: Adam Berlie

      Adam Berlie answered on 8 Nov 2018:

      I’m not quite sure what you mean… If you heat water up then you may lose some water as steam, but then if you cool it down quickly it looses a lot of energy and the molecules stop whizzing around and everything become cold. Or do you mean if you freeze it to ice very quickly? If you heat the water up then the whole system has lots of energy, everything is moving very quickly so the molecules are whizzing about. If you cool it very quickly into ice, then this is a process known as quenching. People within these chats have spoken a lot about making crystals where everything is very nicely arranged – all the molecules fit together properly and everyone is happy. If you cool liquid water down very quickly or quench it, you may still form a solid, but rather then all the molecules being very nicely sat together, they will all be in a bit of a jumble. So everything, although solid, is a mess on the molecular level, the term for this is amorphous. You form an amorphous solid.

    • Photo: Rebecca Roddan

      Rebecca Roddan answered on 8 Nov 2018:

      As with Adam, I’m not sure what you mean but I’ll try and answer what I think you mean!

      When water gets really hot, above the boiling point of 100 degrees celcius, this amount of heat energy is capable of breaking the bonds between different water molecules (called hydrogen bonds). This results in it turning from a liquid to a gas.

      When water gets cold, the water molecules vibrate less and eventually when the temperature gets below zero degrees celcius, water turns to a solid (ice). When this happens, the molecules arrange themselves in a specific way that means that ice is actually less dense than water (this is why ice cubes float in water).

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