The basic experiment suggested placing a hard boiled egg in cola to see what happens since the shell of an egg is very similar to the enamel on our teeth. We went farther. We wanted to see specifically what in the soda might be hurting the enamel, the sugar, the carbonation or the carmel coloring.
We put one egg each in regular Coke, Diet coke, and seltzer. We watched them and tested them every few days over the course of two weeks.