WORKSHEET 15

Activity - A PET Cloud

Equipment

• large clear plastic PET bottle with cap. The label should be removed
• water
  
• matches

Procedure

1. Pour a little cold water into the bottle.
2. Screw on the cap and shake the bottle.
3. Squeeze and release the bottle a few times. (Does anything happen inside the bottle?)
4. Open the bottle and drop a lit match into it. (The match will go out when it hits the water.)
5. Screw on the cap and shake the bottle.
6. Squeeze and release again

Questions

Answer the following questions in the spaces provided.

1. Why does shaking the bottle help the experiment?
   
   
   
   
   
   
   
   
   
   
2. Why do you think the smoke from the match helps the cloud form?

Explanation

When water condenses, the droplets may form clouds. Particles of dust help droplets to form. Without tiny particles in the air, clouds would not form.

Droplets in clouds are small enough to be supported by the air. When they join together to form larger droplets they can no longer be supported and rain falls. It takes about 1 million cloud droplets to make and average size rain drop.

Extension Activity

Fact File

Cloud particles consist of tiny droplets of liquid water or ice. The size of these particles ranges from approximately 5 to 75 microns (0.005 to 0.075mm).

This activity is courtesy of
the Cooperative Research Centre for Southern Hemisphere Meteorology