For the experiment you need:
- bicarbonate of soda
- food vinegar
- a teaspoon
- for measuring liquids: a syringe or decilitre measure
- a transparent jar or drinking glass
- an empty balloon
- an empty bottle (0.5 l)
- a funnel (you can also make a funnel out of baking paper, for example)
- First, observe the reaction of the bicarbonate mixed with the vinegar.
Put two teaspoons of bicarbonate in the jar. Then measure out 10 ml of vinegar into the syringe. Squirt the vinegar over the bicarbonate and observe: what do you see? What do you hear? How would you describe your observations?
- For the following, measure out 30 ml of vinegar into the bottle. Then put five teaspoons of bicarbonate into the balloon. Then thread the opening of the balloon over the opening of the bottle. Hold the balloon up so that the bicarbonate flows into the bottle. What observations can you make?
- Think together about why the balloon is growing. How could the balloon be made even bigger?
- Photograph and film the different stages of the experiment with the child. Think about which parts of the experiment are important to present. How should they be presented so that the reader gets as clear a picture as possible of what has been done?
To support the adult:
- Encourage the child to describe their observations at each stage. Observations can be documented, for example, by drawing, recording comments, photographing and filming.
The balloon grows because the bicarbonate and the vinegar create a reaction that forms gas. The gas formed is carbon dioxide.