We don't like fog when we're outside, but it's fun to make your
own!
What you need:
- Large bottle
- Hot water
- Sieve
- Ice cubes
How to:
- Fill the bottle with hot water.
- Pour out the water, leaving around two centimetres in the
bottom.
- Place the sieve over the mouth of the bottle and put around
four ice cubes in the sieve.
What did you notice? You should see a fog start to form. To make
it easier to see the fog, put the bottle against a dark
background.
What's happening?
Cold air from the ice cubes causes the water vapour in the warm,
moist air to condense into water droplets. Just like clouds, fog
forms when water vapour condenses into tiny water droplets in the
air. The difference is that in fog, the water vapour normally comes
from water on the ground such as the sea or lakes. This is why fog
forms close to the ground. In clouds, water vapour is present high
in the Earth's atmosphere.
Try making a cloud in a
bottle. For more exciting weather experiments, visit Weather Labs.
Did you know?
The foggiest place in the world is Grand Banks, Newfoundland,
Canada. It has over 200 foggy days per year!
Main image (c) j.o.h.n.
walker