NON-LIVING THINGS 205 



the water rises in the tube a few inches. Mark the height 

 of the water in the tube by tying a string around it at the 

 point to which the water rises. Heat the flask slowly over 

 a gas or alcohol flame, and note the rising of the water in 

 the tube. Why does it rise? Does it expand as much as 

 air? Which is more elastic, air or water? Water which 

 has been expanded to a gaseous form (steam) is very 

 elastic. 



The expansion of water by freezing may be taken up 

 here or in connection with dynamic geography. Experi- 

 ments along this line are very interesting to pupils. Fill 

 a heavy glass bottle, a small necked one is best, and stop 

 with a tight-fitting cork. Place in a freezing mixture of 

 broken ice and salt. In a few minutes the bottle is broken 

 in pieces by the expansion of the freezing water. The ex- 

 periment is more striking if a short piece of heavy iron pipe 

 is used instead of the bottle. The pipe should be capped 

 at the ends with the regulation caps or plugs used by 

 plumbers. 



For the purpose of showing the expansive action of heat 

 upon metals, secure a piece of brass or iron tubing about 

 an inch in diameter and six inches long and a solid brass 

 or iron ball which will just pass through the bore of the 

 tube when both are cold. If the tube is difficult to get, 

 an iron ring will answer the purpose. Heat the ball a few 

 minutes, and it will be found too large to go through the 

 tube. Set the tube upright in a shallow vessel with the ball 

 resting in the opening at the top. Pour cold water upon 

 the ball, which, upon cooling, passes easily through the tube 

 as before. Another method of showing the same effect is 



