EXERCISE 6 



Whenever a change takes place, there is not only a rearrangement of matter, but there is also a 

 change in what we call " energy." For example, when two solids (matter) are moved against each other, 

 their motion (energy) is changed into heat (energy) ; when two solids (matter) are struck 

 against each other, their motion (energy) is changed into sound waves (energy). 

 Problem. Can heat be changed to motion ? 



What to use. A flask of colored water, closed with a one-holed rubber stopper; 

 a long piece of glass tubing connected as shown in diagram ; a source of heat. 

 What to do. Apply heat and note its effect upon the water. 

 Record. Describe changes that take place : 



WHAT WAS DONE 



How MATTER CHANGED 



ENERGY CHANGES 



Questions. 1. Is there really more liquid or less liquid than there was before heating? 

 2. What do you suppose happened to the liquid to make it seem of a different quantity ? 

 Home exercise. Make a list of six ordinary events or actions and tell what change or changes took 

 place in the matter and what changes took place in the energy. 



[6] 



