72 



JUNIOR GRADE SCIENCE 



the other block and having the straw pointer fixed to it. Heat the bar with 

 a flame and notice that the pointer moves on account of the expansion o* 1 

 the iron. 



FIG. 57. A flat bar of metal having one end kept from moving by a heavy mass is 

 heated and the other end moves the pointer, because the bar gets longer. 



ii. Expansion of liquids. (a) Procure a 4-oz. flask and fit it with a cork. 

 Bore a hole through the cork and pass through it a long glass tube which 

 fits tightly. Fitt the flask with water coloured with red ink. Push the 



FIG. 58. The expaasion of 

 a liquid. 



FIG. 59. Experiments to show the 

 expansion of air by heat. 



cork into the neck of the flask and so cause the coloured water to rise up 

 the tube. See that there is no air between the cork and the water. Now 

 dip the flask in warm water, and notice that the liquid soon gets larger and 



