CHAPTER XXIII 



HOW ELECTRICITY IS CONTROLLED IN OUR 

 HOMES 



Problems. i. To determine how electricity is produced 

 and controlled. 



2. To find out what effect different lengths and sizes of 

 wire have on the electric pressure and current. 



3. To find out how the house is protected from excessive 

 currents. 



4. To learn how to read the electric meter. 



Experiment. i. Make a wet cell and show presence of an elec- 

 tric current. 



Project I. To INSTALL A NIGHT LIGHT IN MY BEDROOM. 



1. Purpose of the light? 



2. How will you arrange wiring? Locate battery, switch, and 

 lamp. Make plans of connections. 



3. What materials are needed? Cost? 



4. Install the light system and make a report on it. 



Suggested Projects. 



1. THE TRANSFORMER VS. DRY CELLS TO OPERATE A DOORBELL. 



Find the cost of a doorbell transformer for use on electric light cir- 

 cuit, and cost of operating it. Find cost of operating doorbells on 

 dry cells. Considering cost and convenience of uninterrupted serv- 

 ice, which system would you recommend ? 



2. FIND THE COST OF OPERATING VARIOUS ELECTRIC DEVICES PER 



HOUR. Learn how to measure small amounts of electric power by 

 timing the revolutions of the dial in the wattmeter. 



359 



