The Water Cycle

  1. Evaporation: The sun causes the water on the surface to evaporate.
  2. Condensation: As the water rises it cools and condenses to form clouds of water vapour.
  3. Precipitation: Rain and snow fall from the clouds.
  4. Run off: Water runs off the surface of the land. Water also sinks into the soil, where it is absorbed by plants and once again released into the air

What is evaporation?

Evaporation is the changing of a liquid to a vapour.

What is condensation?

Condensation is the process of changing a vapour to a liquid.

Experiment:

To show the presence of water vapour in the air.

Method:

  1. Fill a dry test tube with ice.
  2. Place the test tube in a stand, and leave it in the air for a few minutes.

Result:

Drops of liquid collect on the test tube. This liquid changes blue cobalt chloride paper to pink.

Conclusion:

This liquid is water, and condensed from the water vapour in the air.

Note: The amount of water vapour in the air is called humidity

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