94 ELEMENTARY GENERAL SCIENCE CHAP. 



(Fig. 42). Notice the length of rod immersed and how many 

 cubic centimetres or grams of water are displaced by the rod. 

 Repeat the experiment with turpentine, brine, and methy- 

 lated spirit, in each case running off the liquid displaced and 

 weighing it. Record your observations as below : 



Length of immersed portion of rod cm. 



Length of whole rod cm. 



Weight of rod gin. 



Weight of liquid displaced gm. 



A comparison of the results thus obtained will show that the 

 weight of the whole rod is equal to the weight of the liquid 

 displaced by the portion of the rod immersed. 



EXPT. 82. Procure a wooden cube or rectangular block. 

 Slightly oil the block and place it in a glass of water. Mark 

 upon it with a pencil where the surface of the water touches 

 it. Then take out the block and determine the volume of the 

 immersed portion in cubic centimetres. You will then know 

 the volume, and therefore the weight, of the water displaced. 

 Record as below : 



Weight of block gin. 



Volume of immersed portion of block ... c.c. 

 Therefore weight of water equal to 



the immersed portion of block gm. 



In this case, again, it will be found that the weight of the 

 whole block is equal to the weight of the volume of water dis- 

 placed by the portion immersed. 



EXPT. 83. Procure a large wooden pill-box, and float it, 

 by adding shot, without the cover, in water, up to a mark 

 which you have made beforehand upon the curved surface. 

 Show, as before, that the weight of the volume of water dis- 

 placed is equal to the weight of the whole box and the shot. 

 Repeat the experiment by putting more shot in the box, and 

 so making it sink deeper in the water. 



EXPT. 84. Fill the graduated jar with water up to a certain 

 mark, and then float a test-tube in it. Put sufficient shot into 

 the test-tube to make it float upright ; and, when it does so, 

 notice the volume of water above the initial level of the water 

 in the jar. The weight of this water in grams will be equal 



