Inflate a balloon with vinegar

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An exciting end to a night of experiments! Beavers love watching the balloon fill with gas from the vinegar and bicarb mix.


small plastic bottles (500ml)- 1 per group.
tub of baicarbonate of soda per group.
bottle of vinegar per group.
1 round balloon per group.
1 teaspoon per group.


This works best in small groups (depending on the number of leaders you have) so that each Beaver gets the opportunity to join in. You could have a race to see whose balloon inflates quickest or biggest. WARNING - THIS COULD GET MESSY IF THE BALLOON BURSTS!!
About a third fill the plastic bottle with vinegar.
The Leader stretches the mouth of the balloon to make it easier to add the bicarb.
Leader holds open the neck of the balloon whilst the Beavers take it in turn to add teaspoons of bicarb - about 12 in total should be enough.
Carefully place the mouth of the balloon on to the neck of the bottle, making sure the bicarb stays securely in the bottom of the balloon.
Make sure the balloon is securely pushed onto the bottle.
Make sure the Beavers stand back and don't put their faces too near to the balloon for the next bit.
Ask the Beavers what they think will happen when you tip up the balloon.
Lift the balloon so that the bicarb tips into the bottle.
Ask the beavers if they can explain what happened and why.


  • balloon
  • bicarbonate of soda
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  • vinegar

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