45. Condensation, particles and heat transfer

Flashcard No.9-

Condensation, particles and heat transfer

If you make yourself a cold drink, put some ice cubes in it, you'll often find that the surface of your glass becomes wet with small droplets of water forming on the outside. So what's happening here?

This is all about condensation. Water vapour molecules in the air collide with the cool surface of the glass and lose their kinetic energy. Because they no longer have enough energy to escape again as a gas, they form liquid bonds - and that's why the outside of the glass becomes wet.

You're effectively extracting water from the air (from it's gaseous form), making it become a liquid by taking away its kinetic energy. This process means that heat energy is transferred from the liquified water vapour to the glass, which warms up slightly. It's the opposite of evaporation.

GCSE Physics Keywords: Condense, Condensation, Gas, Liquid, Kinetic energy, Liquid bonds, Heat transfer

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