Ask A Scientist© Biology Archive

Author:      cdahncke
Text:        I need to know why an egg that has been "rubberize" by soaking it 
in a vinegar solution will gain in weight and size when soaked in water, and 
shrink when soaked in corn syrup.

Response #:  1 of 1
Author:      Jim Murray
Text:        This has to do with osmotic pressure and the concentration of 
solutes in a solution.  When you rubberize an egg, you allow it to change size 
when it gains or loses water.  Soaking it in water, which has fewer solutes 
(salts usually) than the egg does, will cause water to rush into the egg to 
surround the solutes in the egg.  This is because a system has a tendency to 
reach an equilibrium.  The concentration of solutes in the egg will decrease 
as water goes into it, and the concentration of solutes in the water will 
increase as the solutes in the egg are leached out.  Similarly, corn syrup has 
a very high concentration of solutes (sugars).  The corn syrup is a solution 
that will pull water out of the egg, causing it to shrink.