MECHANICS OF IMPLEMENTS AND TOOLS. 177 



Mechanics of Implements and Tools.— The Ontario 



Course suggests the study of the applications of mechanical 

 principles in the construction of farm and household imple- 

 ments and tools. Some pupils are very strongly attracted to 

 this kind of investigation. ' *I reformed him," said the teacher 

 of a rather incorrigible boy, "by the accident of asking 

 him to show to the class and explain a telephone he had made." 

 Making tops, kites, pumps (p. 23), motors, etc., and studying 

 the principles of their action is excellent education. Important 

 facts in physical science are taught very effectively if these 

 home-made or purchased toys are subjected to discussion and 

 explanation in the class-room. Keep eye and ear open for 

 opportunities to introduce such lessons. 



All the tools and machinery used on the farm and in the 

 household and shop can be analyzed into six simple forms — 

 the lever, the wheel and axle, the pulley, the inclined plane, 

 the wedge and the screw. By the Nature Study method the 

 teacher would not start out by describing the lever, denning 

 weight and fulcrum and then seeking applications, but would 

 begin with the last and lead to the discovery of the principle 

 and recognition and definition of the parts. How is power 

 applied with a spade, with a pick, with a crowbar? When 

 enough examples have been compared to discover the principle 

 it may be sought in less explicit cases — in scissors, pincers, 

 steelyards, balances, pump-handle, claw-hammer, etc. Another 

 type of lever is used in nut-crakers, lemon-squeezers, wheel- 

 barrow, boat-oar, turnip-cutter, and a third type — the power 

 between the fulcrum and the weight — in ladder-raising, 

 shutting a door by pushing near the hinge, pitching hay, 

 lifting a weight in the hand, holding a foot off the ground. 

 A type lesson on the lever is given in " Public School Nature 

 Study," pp. 191-194. 



The wheel and axle is seen in many of the farm machines, 

 usually in combined wheelwork, as in a fanning-mill or reaper, 



