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Lesson 5 of 10

Warming them up

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6 min

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An ice cube on a warm plate turns to water. Boil the water and it turns to steam. Steam is water vapour, water as a gas.

Cold ice: particles are packed and vibrate a little.
Step 1 of 4
  1. Cold ice: particles are packed and vibrate a little.
  2. Warmer: they vibrate harder. At last they leave their places.
  3. Liquid water: particles slide past each other.
  4. Hotter: particles break away and fly off as vapour.

New words

  • Melting point — the temperature at which a solid becomes a liquid.
  • Boiling point — the temperature at which a liquid becomes a gas.

The rule

Warm a solid and its particles vibrate more. At the , they leave their places. The solid becomes a liquid. At the , they move far apart. The liquid becomes a gas.

Melting points
SolidMelts at
Ice0 °C
Tin232 °C
Copper1085 °C

Water boils at 100 °C. That is its .

Water also turns to vapour slowly below its . That is evaporation.

Slide the temperature. Watch the particles.

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