288 ILLINOIS STATE ACADEMY OF SCIENCE 



graph sets and sending messages to each other, either in the 

 laboratory or by installing the sets in their homes. 



The making of induction coils, spark coils and other 

 parts of wireless outfits are good projects. Not only do 

 students of physics make most of their wireless apparatus, 

 but boys who never have had physics are doing it. I feel 

 sure that anyone present can relate instances of keen in- 

 terest shown by students when allowed to make, or assist 

 in installing, a wireless in the school, or when making their 

 own outfit at home. 



To mention briefly a few other practical projects in this 

 branch of physics, I will suggest that the electroplating 

 project, such as copper plating and nickel plating, be given. 

 Let the students assemble the apparatus and actually plate 

 things. Electrolytes and ionization are taught much more 

 easily after a first-hand acquaintance with electroplating. 

 Different solutions made with distilled water, using in turn 

 salt, acid, sugar and glycerine, may be tested for conduct- 

 ing power, thus showing ionizing and non-ionizing sub- 

 stances. 



Why not begin the study of the storage battery by hav- 

 ing the students construct simple ones with pieces of lead, 

 a pint fruit jar and dilute sulphuric acid? After charging 

 and testing this storage cell by ringing bells, the construc- 

 tion and workings of the regular battery will be understood 

 more easily. 



Interest and profit are gained by having students make 

 Geissler tubes out of old electric light bulbs. The glowing, 

 rarefied gas in such bulbs stimulates interest in another 

 line, and may well lead to the mysteries of X-Ray produc- 

 tion. 



Making arc lights, using home-made electromagnets to 

 draw the carbon sticks apart when the current is turned on, 

 teaches the principles involved in street lights and lights 

 used in stereopticon lanterns. 



Continuing from this the electric furnace may be con- 

 structed, using electric light carbons enclosed in hollowed 

 out fire brick, or in a box lined with some refractory 

 material. 



