Stores 3ner0g in Water* 183 



as before stated, is a movement of the atoms 

 of matter, and temperature, as it affects the 

 thermometer, is a measure of the intensity of 

 motion exhibited by these atoms. 



In the experiment of the block of ice that in 

 the beginning is 10 degrees below the freezing 

 point, as shown by the thermometer, the mole- 

 cules have a definite intensity of motion. The 

 intensity of this motion increases when heat 

 is applied until it reaches 32 degrees, when it 

 remains stationary until all of the ice is 

 melted. At this point there is a rearrange- 

 ment of the molecules of water as it assumes 

 the liquid state. To perform this rearrange- 

 ment requires a certain amount of work done, 

 which is analogous to the winding up of a 

 weight to a certain distance. There has been 

 energy used in winding up the weight, but 

 that energy now is not destroyed, nor still in 

 the form of heat, but is in the potential state 

 ready to do some other kind of work. So, the 

 heat that has been applied to the melting ice 

 has been utilized during the process of its 

 liquefaction in rearranging the water 

 molecules and putting them in a state of 

 strain, so to speak, like the weight that is 

 wound up to a certain height. There is a cer- 

 tain amount of potential energy that is stored 

 in the molecules of water that will be given up 

 and become active energy in the form of heat, 

 if the water is again frozen. To melt a cubic 



