Speedy Experiment – Lemon Volcano

I can’t say I’m a big fan of lemons. They’re just like oranges, but a more boring colour and with a horrible taste. But, like them or hate them, with a few simple ingredients, you can turn them into a lemon volcano! You don’t need time or a laboratory for this one; like the tremendous teabag rocket, the test takes less than ten minutes. Furthermore, it uses entirely household materials, so won’t harm the environment!

You will need:

  • A lemon – mine was quite an old one, which was good as it stopped me from wasting food.
  • A spoon
  • A knife (get a grown-up’s help for this one!)
  • Bicarbonate of Soda
  • A spare container; the second ramekin (little dish) in my photograph has a dash of washing-up liquid under the recommendation of another experimenter; however, I found that I didn’t need this.

The method:

1) Cut the two ends off of the lemon with the knife.

2) Use the spoon to core out some of the middle.

This should make a “bowl” shape like the image above.

3) Squeeze out the lemon juice from the lemon-ends into the spare container.

4) Add some bicarbonate of soda to your lemon-bowl.

The lemon juice will react with the soda and create an eruption. If your reaction is underwhelming, add a little of your spare lemon juice…

If you like, try testing the lemon volcano method with other citrus fruit. Does it work with lime? Orange? Grapefruit?

The science:

Bicarbonate of soda contains carbon – it’s in the name (bicarbonate) . When the citric acid in lemon juice reacts with the soda, those carbon dixoide atoms gain two oxygen atom companions each, and become carbon dioxide. Carbon dioxide is a gas, so that creates bubbles in the juice-and-soda – and because quite a lot of it is being produced, the lemon seems to erupt!