Controlling the weather in your hands is a magical experience. This little experiment lets you create a cloud inside a bottle by controlling the essential THREE conditions:
1) Particles in the air
2) High humidity
3) Temperature change
After this little gem, why not see it done on a grander scale using Liquid Nitrogen!
Materials
2L soft drink PET bottle
Matches
Water
Adult
Remember
Matches and fire should be done by an adult.
Pour some water into the bottle and screw on the lid
Squeeze the bottle and see if you can create a cloud.
Remove the lid and light a match. Let it burn half way down the match stick and then extinguish it. Place the smoking match into the bottle and quickly tighten the lid.
Now there is some smoke particles in the bottle, squeeze it again. When you let go, a cloud should form this time.
Keep squeezing and letting go to see the cloud appear and disappear.
Check out the ‘Wacky Science’ video of this experiment and ‘What’s Going On’ series link. They are currently ‘In Production’, so check back soon…..
Clouds form when water vapour (invisible water as a gas) condenses into water droplets (fog or cloud). To condense from a gas back into a liquid a temperature decrease needs to occur.
To begin with we added water and shook the bottle. (picture A) This puts lots of water vapour into the air inside the bottle (makes it more humid). Squeezing the bottle increases the pressure inside the bottle (and also increases the air temp slightly). BUT, no cloud forms. (picture B)
As we added some smoke (picture C), the water droplets in the air have a place to turn back into water droplets. (nucleation sites…… similar to seeding clouds).
When the bottle is squeezed this time, temperature increases as before BUT as we release the bottle (the air temperature decreases), there are sites for water droplets to form and we now see a cloud form. Â (picture D)
Squeeze bottle again: temperature increases and the water vapour vapourises into a gas (cloud disappears)
Release bottle: temperature decreases and water condenses back again top for a cloud.
Controlling weather in your hands. Check out how The Crazy Scientist does this on a BIG scale in the best liquid nitrogen show around. (Nitro-Tastic)
If you would like
– more details,
– pictures of the second half of the experiment
– information on how to investigate this further
– links to everyday examples
– management hints & teaching pointers (5P Teacher develpoment program)
 ….. then why not subscribe to one of the following
(1) Crazy science Club
(2) 5P Teacher Training course called ‘Looney Lab  Classroom Creations‘
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Or you can purchase the ‘Bright Sparkes Guide’ of this demonstration only ($2.50) which has:
- HD pictures of experiment steps
- Detailed explanation of science
- Mini-challenge section (another experiment)
- Making it a ‘Scientific Method’ experience
- Graphing opportunities
- REAL links and descriptions to everyday examples of concept.
Clouds: @ Weather Wiz Kids:Â Website looking at the many types of clouds with animations. Easy to understand
Cloud Types: @ Windows 2 the Universe: Great pictures of the different cloud types
Condensation: The change of state when gaseous water changes its state to liquid water. This occurs in cloud formation due to changes in pressure and temperature.
Nucleation site: This is a small location (usually on a crack in glass, or dust particle) on which reactions can occur. In this case, the dust particles are the sites at which gaseous water can collect and form larger droplets of liquid water (forming fog and therefore a cloud).