24 



LABOEATOEY MANUAL 



the large end of the egg will extend about % of an 

 inch below the cardboard. On the small end of the egg 

 break away the shell to form an opening large enough 

 to insert the glass tube, which 

 should be about 6 inches long. 

 Carefully seal the tube in the egg 

 with the end projecting about half 

 an inch below the shell. Fill the 

 tumbler with hydrochloric acid. 

 Place the cardboard and the egg- 

 over it with the large end of the 

 egg projecting into the acid. The 

 acid gradually dis- 

 solves the shell, ex- 

 posing the thin mem- 

 brane underneath it. 

 When the shell has 

 been removed from 

 the end of the egg, 

 empty the acid and 

 fill the beaker with 

 water. Rinse the 

 acid off the egg and 

 replace the card- 

 board and egg over the tumbler. The water in the 

 tumbler and the contents of the egg are now separated 

 by the egg membrane. Allow the experiment to stand 

 for 24 hours. What change do you note in the tube? 

 How do you account for this change? 



Fig. 7. 



