PAPERS ON PHYSICS 289 



Recently our students obtained some wire of high re- 

 sistance and worked out a number of interesting projects. 

 One was an electric heater, capable of heating a small room. 

 A piece of sheet aluminum was cut and shaped into a reflec- 

 tor, and the heating wire, wound around an asbestos 

 covered porcelain tube, was mounted in front of the re- 

 flector. Some more of the same wire, mounted in six sepa- 

 rate coils in the bottom of an asbestos lined shallow box 

 with metal top, made a serviceable heater that could be 

 used as a foot-warmer, or moderately hot stove or toaster. 

 One student wished to make an electric flat iron. He did 

 so by using some of this resisting heating wire inclosed 

 between suitably insulated pieces of lead for weight. He 

 covered it all with sheet copper, and fastened on a wooden 

 handle. When connected to a 110 volt circuit it worked 

 well. Surely college and high school students are interested 

 and benefited in doing such practical work. 



A little more ingenuity is required for making a Tesla 

 Transformer which will give a 6 to 8 inch spark, but our 

 students have done it after having had an introductory 

 course in electricity. 



When other projects are scarce a little time may be 

 spent profitably in making blue print paper and then tak- 

 ing permanent pictures of magnetic fields about magnets 

 and about current bearing wires. Also simple detecting 

 galvanoscopes, electroscopes and electrophorouses may be 

 made by students and experiments performed by using 

 them in preference to elaborate and expensive apparatus. 



I will mention in closing one other example of project 

 work, and that is in the field of repair work. When some 

 apparatus is out of order, if it is not too delicate and 

 complicated, we give it to capable students to repair. They 

 enjoy such work and often get much out of it, since they 

 must learn how the apparatus is constructed and the prin- 

 ciples by which it works. To mention a concrete case — we 

 have an electric washing machine in our laboratory' for 

 demonstrating one use of the motor, and some time ago it 

 failed to work properly. Some students took the motor otf 

 the machine, dissected it and found that a loose screw had 

 caused a short circuit and partly burned out the armature. 



