This is a raw egg without the shell that is held together by its membrane and actually bounces like a bouncy ball. Brianna really wanted to try this experiment so we put the egg in a cup of vinegar and left it there for a couple days. After the first day we changed out the vinegar and by the morning of the 3rd day the shell came off. It was super cool, but kind of gross too ;) . . . it smelled awful . . . just sayin'