Exploding film pot

This is a very simple experiment.

You will need

A weak acid (e.g. vinegar), Sodium bicarbonate (bicarbonate of soda) or similar, a film pot or other light container with a lid that can pop off.
Eye protection and an area which does not mind getting messy.

Method

  1. Put some of the acid in the bottom of the pot
  2. Put some sodium bicarbonate on the lid
  3. Read this whole step before carrying it out (and do this quickly)
    1. close the lid
    2. make sure it is closed properly all the way round
    3. Shake it once and place it lid down in the middle of your area that doesn't mind getting messy (I used a wash basin outside)
    4. Wait for it to explode, don't touch it if you do you could get covered in bubbles.

Explination

Obviously some sort of gas is produced, what gas do you think it is?
Why is it important to make sure the lid is fully sealed?
How does the amount of acid and sodium bicarbonate used affect how big an explosion there is? (do it again to find out)

Acid + carbonate goes to ....

Our Experiences

The first time we did this experiment we used some tartaric acid we had left over from two days before. There was a nice impressive pop the pot flew into the air and bubbles were thrown around. However J made the mistake of shaking it to try and speed up the reaction as it took a few seconds to start, consequently she got bubbles on her clothes, don't do that. Subsequent experiments using vinegar were similarly effective. The pot can fly a long way, so make sure there is nothing really delicate that it can hit. e.g. priceless glassware on the edge of a bench.
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