Fill your glass with the carbonated liquid until it is about 3/4 full.
If you have them, drop two or three grapes into the glass. What happens?
Now, drop a few raisins into the liquid and observe. Do the raisins act differently from the grapes? Why do you think this is?
If you have them, try dropping in a few other types of berries. What happens?
Hmm... it seems nobody's added a conclusion for this experiment yet. You can suggest one here.