Fizzy Trays

These fizzy explosions of colour will provide hours of fun!

You will need

  • A tray (a baking tray works well)
  • Bicarbonate of soda/ baking powder
  • Clear vinegar
  • Small pots x 2
  • Food colouring
  • Teaspoon or medicine syringe


  1. Sprinkle some bicarbonate of soda onto your tray evenly.
  2. Into your small pots pour some clear vinegar and add some food colouring (different food colouring into each pot).
  3. Using a syringe or teaspoon transfer the vinegar, a little at a time, onto your tray and watch the bicarbonate of soda fizz as it reacts with the vinegar.
  4. Using both the colours, make some patterns and craters over your tray while you enjoy the fizzy eruptions.


  • What if you try adding a small squirt of liquid soap to the vinegar. Does that make the reaction even more bubbly?
  • If you have access to a variety of colours try making different colourful trays. Which colour combinations work the best?
  • Does it also work if you use lemon juice instead of vinegar?


There’s lots of fizzing going on in this experiment, but what is causing it? Vinegar is an acid, and bicarbonate of soda is a base (alkali). When these two ingredients come into contact with each other they react and produce a gas called carbon dioxide. This gas production causes all the fizzing we see on the tray! As you may have also seen if you tried the investigation, it also works with lemon juice! This is because lemon juice is also an acid. We add food colouring to make this experiment look even more awesome!

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