A YEAR IN SCIENCE 



23 



Apparatus 



Animal membrane 



Thistle tube 



Water 



Molasses 



Twine 



Glass jar 



Ring stand and clamp 



Rubber tubing 



Clamp 

 Card board 



Egg 



Glass tubing 

 Sealing wax 

 Hydrochloric acid 

 Glass tumbler 

 Bunsen burner 



Directions: A. Over the stem end of the thistle 

 tube fit a small piece of rubber tubing. Close this 

 tightly with a clamp. Fill the bulb of the tube with 

 dilute molasses. Over the 

 end of the bulb securely tie 

 an animal membrane, being- 

 careful to exclude all air 

 bubbles. From the ring- 

 stand suspend the tube with 

 the bulb in a jar of Avater. 

 Mark the level of the 

 molasses in the tube. Note 

 the color of the water in the 

 jar. At the end of one hour 

 repeat the same observations. 

 Observe again at the end of 

 twenty-four hours,. 



Fig. 6. 



What changes have taken place! 

 Has-any molasses passed into the water? How do you 

 know ? Has any water passed into the molasses ? In 

 which direction has diffusion taken place more rapidly ? 

 How do you know? 



B. In the cardboard cut a hole large enough so that 



