What children will learn
- Observe a chemical reaction producing a gas (carbon dioxide)
- Make a prediction and test it
- Describe changes using science words
You'll need
- Bicarbonate of soda (2 tablespoons)
- White vinegar (½ cup)
- A small cup or bottle
- A baking tray
- Food colouring and a squirt of dishwashing liquid (optional)
Safety first
- Adult supervision required.
- Keep vinegar away from eyes; rinse with water if it splashes. Wearing sunglasses or swimming goggles is a good idea.
- Don't put the lid on a bottle — the gas needs to escape.
- Don't drink the mixture.
How to do it
- Set up outside or in the sink. Stand the cup on the baking tray.
- Put 2 tablespoons of bicarb soda in the cup. Add a few drops of food colouring and dishwashing liquid for extra foam.
- Ask: ‘What do you think will happen when we add vinegar?’ Write or draw the prediction.
- Pour in the vinegar and step back to watch the eruption.
- Talk about it: the bubbles are a gas called carbon dioxide, made when the two ingredients react.
- Experiment: does more vinegar make a bigger eruption? Does warm vinegar work faster?
Make it easier
Just enjoy the fizz and talk about ‘bubbles’ and ‘gas’.
Make it harder
Measure the foam height with a ruler for different amounts and record results in a table.
Parent tip: The prediction and the ‘what if we change…’ experiments are where the real science happens.
Fantastic work! Every little step helps you grow.