Watch your favourite school snack dance in soda water!
- 10 x Sultanas
- 1 x Litre of Soda Water
- 1 x Transparent Contrainer
- Pour the soda water into the container.
- Gently add the sultanas one at a time to the soda water.
- Watch them float to the surface and then sink down to the bottom.
- How long will this dancing go on, and why?
Why is it so?
But they won't float on the surface for ever! Once the sultanas reach the surface, the bubbles supporting them pop! Causing them to sink again. But they will rise again as new bubbles lift them up! Will this rising and sinking motion go on forever?
No it won't. The rising and sinking motion will stop once all the carbon dioxide has escaped (soda goes flat). You will also notice that with time the dried sultanas will have absorbed some water and become too heavy to rise. You will also notice that the sultana will expand and cause its skin to become smooth, leaving no crevices for the bubbles to wedge between.
Instead of using soda water you could create a bubbly liquid by mixing vinegar and baking soda, or experiment with other objects that can dance too!