Balloon In A Bottle

A demo that really sucks!

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Purpose -

A wizard that shows the effects of air pressure against a vacuum, and the difference in volume between gases and liquids. 

Nature - 

Demonstration

Materials - 

A balloon, water, a 1 litre boiling flask, a Bunsen burner tripod and gauze mat, a container of ice water 

Method - 

Put about 150 ml of water into the boiling flask and put on to heat.

When the water has just started boiling and steam is coming out of the top of the flask, turn the heat off.

Stretch the mouth of the balloon over the mouth of the flask.

Place the flask into the ice water and watch the balloon suck into the bottle and inflate inside.

Safety -

Care with flames, hot liquids and hot apparatus.

Explanation -

The steam fills the flask, forcing the air out.  Once the heat is off and the balloon in place, the steam starts to cool and condense taking up less space.  This happens very quickly once the flask is in the ice water.  The resulting vacuum sucks the balloon down into the flask and inflates it there.

Notes -

This wizard shows the same concepts as the Can Crush Demo, but in a cheaper and very different way.  

To remove the balloon carefully lift one corner of the balloon mouth away from the edge of the flask so that air is able to flow into the bottle.