240 ILLINOIS STATE ACADEMY OF SCIENCE 



On account of these two physical laws the hot water would 

 cool much more rapidly than the cold water and conse- 

 quently freeze sooner. ' ' 



Another student went to her home near a thrifty, small 

 city in central Illinois on Friday evening, January 27. 

 On Saturday her father called an intelligent and exper- 

 ienced plumber to do some repair work on the farmhouse 

 plumbing. The student put the question to the plumber, 

 whether hot water or cold water exposed to zero tempera- 

 ture would freeze the quicker. The plumber quickly an- 

 swered that the hot water would. He was certain be- 

 cause in his experience it was invariably the hot water 

 pipes of the hot Avater heating systems which freeze and 

 bnr>=>t and not the cold water pipes of the water system. 

 Accepting this plumber's observations as being correct, 

 some of us may be inclined to ^eek knowledge relative to 

 the location of the hot-water pipes and cold-water pipes, 

 especially in reference to the outside walls of the house. 



It is my experience that in a physics class where the 

 practice is encouraged, hundreds of practical questions 

 pertaining to the environment of the class and the com- 

 munity in which they live will be asked. Few, if any, of 

 these questions are to be found in our ordinary textbooks 

 or suggested in our manuals. In my judgment, in the 

 course of the development of each unit of instruction 

 students should be led to see and to study the relations of 

 the principles involved as they are found in commonplace, 

 everyday environment. From a class which has grasped 

 this conception of the function of science study, practi- 

 cal questions will be forthcoming by the hundreds, and it 

 is the most important function of the recitation or the 

 laboratory period in a science course to answer such 

 questions. 



Illustrative of the type of questions I have in mind, per- 

 mit me to state a few of them : 



1. Where electric service is available, electric light- 

 ing has very generally displaced gas lighting. Generally, 

 we also use the electric flatiron in preference to the gas or 

 coal-heated flatiron. Why have not, likewise, electric 

 stoves and electric heaters displaced gas stoves and coal 



