Dancing Raisins

What you need

• Clear cups, 2 clear glasses
• Water, enough to fill 1 glass
• Plate or tray, 1 tray to stand the glasses on (optional)
• Raisins, 8 to 10
• Fizzy water, 1 cold bottle
• Jug, 1, or a bottle
• Towel, 1
• Bowl, 1 small dish

How to do it

Grown-up prep: Set out two clear glasses on a tray, a fresh bottle of fizzy water, plain water and a handful of raisins. Raisins are a choking hazard for children under 4, so you hold and drop them for little ones. Glass can break, so keep the glasses on the tray and stay close. Use clear plastic cups if you prefer.

1. Stand both glasses on the tray, then pour fizzy water into one. Ask for help if you need it
2. Fill the second glass with plain water to the same height. Ask for help if you need it
3. Drop 4 or 5 raisins into the fizzy glass. Ask for help if you need it
   Ask: Do you think the raisins will sink or float?
4. Watch closely! The raisins sink, then float up, then sink again.
5. Spot the bubbles on a top raisin, then watch them pop.
6. Now drop 4 or 5 raisins into the plain water. Ask for help if you need it
   Ask: Do you think these raisins will dance too?
7. Compare the two glasses side by side.
8. A grown-up tips out the raisins and puts the glasses away. A grown-up does this
9. Now show your friends! Which tiny swimmer will dance longest next time?
   Ask: Who else could you show the dancing raisins to?

Play it again

• Raisin race: pick one raisin and time how long one trip up and down takes.
• Mystery swimmers: with a grown-up, try a grain of rice or a bit of pasta and guess which will dance.
• Going flat: watch the glass for a few minutes and see if the dancing slows as the water goes flat.