290 



EXPERIMENTAL GENERAL SCIENCE 



17. Have a classmate touch the back of your hand, cheek, finger tips, 

 etc., with the points of a pair of compasses. Where can you distinguish 

 the two points when closest together? 



18. Draw a thin piece of ice slowly across the back of the hand and 

 mark with a pencil the points where cold is felt. Make the same experi- 

 ment with a wire dipped in hot water. Does the same point perceive 

 both heat and cold? 



19. Why is it difficult to detect the flavor of hot food? 



