wooi.Hi-LLJ PHYSICAL XATURE-srCDY 9 



apartment houses. When the public demand comes upon us 

 with full force, it will make our present teaching of physics and 

 chemistry in schools and colleges seem foolish. The study of 

 machines will not then begin and end with a few formulas con- 

 cerning the so-called "mechanical powers". 



Of course, physical science deals with much besides ma- 

 chines. It furnishes answers to nine tenths of the questions 

 which the children ask, and even biology itself is three quarters 

 physical science. It is the first subject which the child volun- 

 tarily studies before he begins school and it is the only study 

 which he persists in, during all his school days, with the help 

 of his teachers and elders if he can get it, otherwise in spite of 

 them. Xo year of school should be without it. I am not par- 

 ticular what we call it. "Nature-Study" is good enough, with- 

 out any other limiting adjective. What is wanted throughout 

 the whole elementary school is not the teaching of the prin- 

 ciples of science, as a catalogue, but the cultivation of instincts, 

 and the accumulating, comparing, and interpreting of exper- 

 iences. The person who learns to ride a bicycle, swim, walk 

 on stilts, fly kites, play marbles, ride horse back, sail a boat, play 

 billiards or tennis, or golf, is acquiring experiences which raise 

 a multitude of questions and prepare the way for understand- 

 ing their answers. The finding of these answers constitutes the 

 study of physics. Laws of motion are simple enough if learned 

 by experience and without quantitative treatment. 



i. You ride standing in a street car holding on to a strap; 

 when the car starts suddenly you pull hard upon the strap to get 

 your body in motion because "a body at rest tends to continue 

 at rest", and when the car stops abruptly you pull hard to make 

 your body stop moving because " a body in motion tends to 

 continue moving", and when the car rapidly turns a corner 

 you pull hard to bring your body around the corner because 

 "a body in motion tends to continue moving in a straight 

 line". So much for the first law. 



2. Now suppose you jump out of an upper winow and 

 jump away from the building so as not to land on a picket 

 fence. You depend upon gravity to bring you down, regardless 

 of the fact that you have projected yourself horizontally to es- 

 cape the fence. If the window is 16 feet from the ground and 

 you jump horizontally at the rate of 10 feet per second you will 

 reach the ground in one second and land ten feet from the 



