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Experiment

The Fizzy Volcano Lab

Build a small clay volcano and set off a foaming, fizzing eruption with baking soda and vinegar.

Ages 5–920–40 min1–3 kids

Shape a small volcano cone from play dough or clay around a cup, then load the cup with baking soda, a squirt of dish soap, and food colouring before pouring in vinegar to trigger a foaming, fizzing eruption. Rebuild and re-erupt with different vinegar amounts to compare eruption size.

What you need

  • play dough or clay
  • a small cup
  • baking soda
  • vinegar
  • dish soap
  • food colouring (optional)
  • a tray to contain the mess

How to do it

  1. 1Build a cone shape from play dough or clay around a small cup on a tray.
  2. 2Spoon baking soda, a squirt of dish soap, and a few drops of food colouring into the cup.
  3. 3"Ready for eruption?" Pour vinegar in and watch the foam rise and spill over.
  4. 4Rinse and reload, testing whether more baking soda or more vinegar makes a bigger eruption.

Variations

  • If clay isn't available: skip the volcano shape and run the reaction straight in a cup or bottle for the same fizzy payoff.
  • How it ends: comparing which combination made the biggest eruption gives the session a clear, satisfying result.

💡 Parent tip

Do this one on a tray outside or in the bath if mess is a concern -- the eruption is more fun when nobody's worried about the mess.

What your child develops

  • Basic chemistry — a genuine acid-base reaction, safe and visible enough to understand at this age
  • Controlled experimentation — changing one variable (vinegar amount) at a time to compare results
  • Sensory engagement — the foam's texture, sound and smell add a full sensory layer to the science

Safety notes

  • Avoid contact with eyes; wipe up spilled vinegar promptly as it can be slippery on hard floors.

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