As with all experiments, please check with one of your adults that they are happy for you to try this. Tell them what’s involved, what you need, and where you plan to conduct it. (Having tested this one myself, I recommend you do it in an area where spillage won’t be an issue – like outside.)

Hypothesis

Have a look at the equipment list and method below, then write down what you think will happen. This will be the idea you will test – your ‘hypothesis’.

Here are some ideas to get you thinking:

1. It’s possible to blow up a balloon using kitchen ingredients.

2. It’s not possible to blow up a balloon using kitchen ingredients.

3. The size of the bottle you use makes a difference to how big your balloon gets when you use kitchen ingredients to inflate it.

4. Balloons explode when you inflate them with kitchen ingredients.

5. Some other idea you’ve thought of yourself!

Equipment

You will need:

1. An empty soft-drink bottle (You could try a variety of sizes.)

2. Food colouring (You could try any colour.)

3. White vinegar

4. A new, un-blown balloon (Note from Kesta: It is very important that your balloon is new and has no holes in it. Believe me. I’ve tested it! The results were startling . . . and messy!)

5. Bicarbonate of soda (This is often called ‘bicarb’ for short, and in America it is called ‘baking soda’. It’s used in the kitchen to make cakes rise when they’re cooking, but it needs to be activated by something acidic like yoghurt, buttermilk, lemon juice or chocolate.)

6. A funnel

Method

1. Put a few drops of food colouring in the bottom of the empty soft-drink bottle.

2. Half fill the bottle with vinegar using the funnel so you don’t spill any.

3. Rinse and dry the funnel thoroughly.

4. Use the funnel to put a teaspoon of bicarb into the balloon through the opening where you’d normally blow it up.

5. Carefully place the neck of the balloon over the top of the bottle, covering the lip of the bottle completely and making sure the bicarb-filled head of the balloon hangs downwards so none of the bicarb gets into the bottle.

6. Now all the preparation is done, lift the head of the balloon up so that the bicarb drops out of the balloon and into the bottle.

7. Watch what happens!

Results and Conclusion

When you’ve done the experiment and found out if your hypothesis was correct or not, feel free to share your results – what happened – and your conclusions – what you found out – by telling us what happened in the comment box below.

Contributing Scientist: Kim R

Variations (Yes! More things to test)

You might like to try the experiment again but testing a different hypothesis.

I’d like to know if it’s possible to inflate the balloon completely. I wonder how much vinegar you’d need? Or how much bicarb . . . (If you go down this track, make sure you check with the chief cook in your family to make sure they have enough vinegar and bicarb in stock for you to keep experimenting.)

Perhaps you’d need a smaller bottle. Or a bigger one.

And what if you don’t use food colouring? Does the balloon still inflate? Is the food colouring important? If it is, why? (If you look at the step by step pictures I took when testing Kim’s experiment, you’ll see I forgot the food colouring. Given my balloon had holes in it, I was really glad I forgot! Can you guess what happened?)

There are so many things to test!

Have fun!

Kesta