Halloween science: Spooky spin on a classic experiment

October 29, 2018

Spooky season is well and truly underway, and what better way to honour Halloween than with a clever display of scientific trickery?

Over half term, you can get your little ones excited about more than their costumes by making your very own erupting Pump-cano (see what we did there?)

This Halloween, we thought that we would show you how to create your very own Pump-cano. You can start by carving your pumpkin as you usually would, making a competition out of who can carve the scariest faces, followed by a spooky twist on the classic volcano experiment using basic household products.

What you will need

  • A Pumpkin
  • A large tray or bowl
  • Carving knife
  • Baking powder
  • Vinegar
  • A bowl or cup that fits inside the pumpkin
  • Food colouring (optional but added fun!)
  • Washing up liquid
  • Water

The Experiment

  1. Cut open the top of the pumpkin and hollow it out.
  2. Carve a face into the pumpkin — the scarier, the better.
  3. Place the pumpkin on a large tray (unless you like a gooey orange mess!)
  4. Fill the bowl or cup with warm water until it is ¾ full. At this point that you can add a couple of drops of food colouring if you choose — we recommend red to fit the Halloween theme!
  5. Add 4–5 drops of washing up liquid into the water and stir.
  6. Put a couple of table spoons of baking powder into the mixture.
  7. Place the bowl inside the pumpkin.
  8. Pour ¼ of a cup of vinegar inside the pumpkin and watch the reaction!

The science behind it

This experiment is a classic example of an acid base reaction. The baking soda is a base and vinegar is an acid. When they are mixed together it causes a chemical reaction where carbon dioxide is released and fizzes out of the pumpkin. The washing up liquid and food colouring are additional components that change the look of the ‘lava.’

If you feel like taking the little ones out of the house for Halloween why not check out what we have on during half term? It’s going to be a scream.

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  •   What is Techniquest?

    Techniquest is an educational charity, with a science centre in Cardiff Bay. Our mission is to embed science in Welsh culture through interactive engagement. We provide a range of services to schools and teachers to complement formal education provision in Wales and work extensively with public audiences.

  •   Where can I park?

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    The Q-Park operates the Cardiff Bay car park in Pierhead Street which is around 8 minutes walk from Techniquest.

    We have agreed a special discount rate for our customers of 15% off all pre-bookings.
    Pre-book and guarantee your space here using the code TECHNI15.

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    We regret that there is no parking on-site at Techniquest.

  •   Who is it for?

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