A fun, interesting experiment for kids of all ages is turning an ordinary egg into one that has been rubberized. Rubberized eggs can bounce somewhat like a rubber ball and feel spongy and smooth in the hand. Using vinegar dissolves the shell, leaving behind the smooth membrane, which is now rubbery. Even though the new rubberized egg will bounce, dropping it from a great height may cause it to break open.
Fill the saucepan 3/4 full with water and bring to a boil. Place the egg in the boiling water and leave for 20 minutes. Drain the water and set the egg aside to cool.
Place the hard-boiled egg in a jar. Glass canning jars work well for this experiment. However, any long jar or cup will do as long as their is enough space in the jar for the egg to be covered by vinegar.
Fill the jar 3/4 full with vinegar. If the egg is not completely submerged in vinegar, fill the entire jar full. Set aside for 24 hours.
Pour the vinegar out, refilling the jar once more. Set the jar aside for five days. The temperature of the room in which the jar is stored does not matter.
Discard the vinegar and rinse the egg with water. The hard-boiled egg shell will now be gone leaving a rubberized egg. Try bouncing the egg on the ground or counter.