What does Coca Cola Diet Coke and Coke Zero do to Calcium Carbonate in a 5-day period?

I'm not exactly sure. im doing a science project right now to find out this question as well. maybe this can help. (sorry, only an 8th grader here:) calcium carbonate is a main ingredient in egg shells. (similar to teeth) so, i soaked an empty egg in coke, and one in Diet Coke. im only on my 2nd day, but what ive found is really surprising. the egg in the coke just turned a brownish color, but the egg in diet coke was this disgustig dark dark brown and was speckled all over. it had cracked alot! and there was also a thin membrane on the egg. yuck! im not sure why, like i said, only an 8th grader, but i hope to find out! hope this helped!

mamsur73