Simple but beautiful experiment to observe and learn about volume and density. And its also calming to look at the dancing raisins!
- Clear Glass
- Clear soda (club soda or sprite or seven up)
Fill the glass with the clear soda. It contains carbon dioxide (CO2), a gas. That's what is seen as bubbles in soda. Now drop few raisins one by one. The raisins sink to the bottom at first. This is because the density of the raisin is more than the water, or the raisin is heavier than the water it displaces.
Density is nothing but the mass of the object divided by its volume.
Density = Mass / Volume
Once the raisin is at the bottom, the CO2 molecules fill the gaps or pores in the raisin, thereby increasing its volume. This in turn reduces the density of the raisin and it raises up to the surface.
The CO2 gas escapes when it reaches the surface making the raisin denser again. So the raisin sinks.
This process continues in a cycle until the raisins are short of gas. Hence we get to see a spectacular show of dancing raisins.
The boys watched the raisin as the bubbles were sticking onto it, the raisin rising to the surface and then loosing the bubbles and sinking.
Questions to ponder:
1. What changes during the experiment?
- The volume and density of the raisins and the amount of water displaced by each raisin.
- The soda will eventually loose the carbon dioxide.
2. What remained constant?
- The mass of the raisin.
3. Use of the experiment:
- Learn some Science
- Loads of fun
- Know that Science is there is day to day life.
- Learn to observe the world
Science is Fun!