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Cloud Formation in a Bottle

Introduction
Demonstrate cloud formation as air pressure drops.
Useful information
Kit List: 

Lemonade Bottle
Matches

Frequency of use: 
2
Explanation
Explanation: 

A smoking (recently blown-out) match is dropped into a lemonade bottle containing a little water. The bottle is closed and then squeezed, held for a few moments, and released. This step may need to be repeated a few times. When you release the bottle clouds should nucleate on the nuclei provided by the smoke particles.

By squeezing the bottle you increase the pressure inside it and also the temperature. This causes the liquid inside to evaporate and form water vapor. Then, when the bottle is released, the pressure decreases again and the temperature drops. This fall in temperature allows the water molecules in the bottle to condense around the smoke particles, forming a cloud.

Risk Assessment
Date risk assesment last checked: 
Thu, 13/12/2018
Risk assesment checked by: 
Grace Exley
Date risk assesment double checked: 
Wed, 12/12/2018
Risk assesment double-checked by: 
Mattlem
Risk Assessment: 

Strike a match, extinguish it and drop it into a bottle containing a little water:

Hazard Risk Likelihood Severity Overall Mitigation Likelihood Severity Overall
Matches Possibility of burns from lit matches. 4 3 12 Ensure that matchbox is not available to be grabbed by children.
Demonstrator to strike matches away from self but also to take care not to strike immediately towards visitors.
Ensure match is no longer lit when dropped into bottle.
Have a cup (or similar) of water to hand to take matches which might be lit and not used.
Run burns under cold water for at least 10 minutes.
Contact a first aider.
2 2 4
Lit matches (dropping) If lit match is dropped on something flammable there is a small risk of fire. 3 5 15 Keep flammable materials away from matches. Have a fire extinguisher available.
Fight fire if safe to do so.
If fire gets out of control evacuate area and call 999.
1 4 4
Water Slip hazard in the event of spillages. 4 3 12 Have paper towels handy and dry any spills immediately.
Contact a first aider in the event of an accident.
2 2 4
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Images
Experiment photos: