Here’s some pictures of an experiment I did with strawberries and dry ice (solid carbon dioxide). Dry ice is frozen carbon dioxide which holds a temperature of -78 °C. What is fascinating is that dry ice does not melt – it sublimes, which means that it turns directly into carbon dioxide gas.
The idea was to create a carbonated fruit which gives a sparkling sensation in the mouth. I have used strawberries, but any juicy fruit with a moist surface could be used. Water melons would be perfect!
The chemistry explained in simple terms:
A schematic drawing of the container:
To prevent the plate from touching the dry ice (which would cause the strawberries to freeze), I put in a wooden triangle first.
Put the plate with strawberry halves on top of the wooden triangle. Cover with a kitchen towel (do NOT cover with a tight fitting cover – remember that as CO2 sublimes, it expands, and this would create a huge pressure ultimately resulting in an explosion), and leave for 30 minutes.
Eat and enjoy!
Update: Carbonated fruit the iSi way!