The Naked Egg

    Kids, do you want to try to remove the shell from a raw egg, without breaking it?

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

    First, place a raw egg in a 1-pint glass jar with a lid (mason jar, for example). Do NOT crack the egg! Then pour in enough clear, white vinegar (preferably from a newly opened bottle) to cover the egg. Close the lid and check it every once in a while over the next 24 hours. What happens? Bubbles start to form on the egg shell immediately, which increase in number as time goes on.

    After 24 hours the shell will be gone (some pieces may be floating). But the egg remains intact because of a thin membrane, though which the yolk can be seen. Why? The chemical in vinegar is acetic acid (a weak acid). Egg shells are made of calcium carbonate, another chemical compound. When these two substances react, carbon dioxide bubbles form from the carbonate and the egg shell disappears.  


    Kathleen Carrado Gregar, PhD, Argonne National Labs 
    [email protected]
    January 1992