Blue bottle

Bouncing sultanas

Sultanas and raisins bob up and down in any fizzy drink

Ingredients and equipment that you will need

A few sultanas or raisins. Old, dry ones tend to work best
A glass of lemonade or other fizzy drink

If you drop a few sultanas or raisins into a fizzy drink, they bounce up and down.

What is happening is that the wrinkles on the sultana trap gas bubbles from the drink. The bubbles work like water wings, making the sultana lighter, so it rises. At the top, the gas bubbles are released making it heavy again, so it drops back to the bottom.

It will carry on bobbing up and down until all the gas comes out of the drink.