262 



ELECTRICITY 



REFERENCES FOR FURTHER STUDY 

 Texts 



Caldwell and Curtis, Science for Today, Chap. 22 

 Clement, Collister, and Thurston, Our Surroundings, Chap. IS 



Hunter and Whitman, Science in Our World of Progress, 

 Unit 7 ; Science in Our Social Life, Unit 7 



Lake, Harley, and Welton, Exploring the World of Science, 

 Chap. 23 



Pieper and Beauchamp, Everyday Problems in Science, Unit 

 14 



Powers, Neuner, and Bruner, Man's Control of His Environ- 

 ment, Unit 5 



Skilling, Tours through the World of Science, Tour 10 



Van Buskirk and Smith, The Science of Everyday Life, Chap. 

 17 



Watkins and Bedell, General Science for Today, Chap. 25 



Webb and Beauchamp, Science by Observation and Experi- 

 ment, Unit 5 (part) 



Wood and Carpenter, Our Environment: How We Use and 

 Control It, Topic 9 



Special references 



Collins, The Book of Electricity 

 Darrow, Masters of Science and Invention 

 Lunt, Everyday Electricity 

 Meister, Magnetism and Electricity 

 Morgan, The Boy Electrician 



WHAT YOU SHOULD AIM TO ACQUIRE FROM 

 THIS STUDY 



1. A knowledge of the units of measurement used for 

 electrical currents. 



2. How to do simple problems in Ohm's Law. 



3. How to read an electric meter. 



4. How to calculate the amount of energy used by an 

 electrical device. 



5. How to calculate an electric bill. 



TEST OF MASTERY OF THE TOPIC 



In your notebook complete the statements, answer the 

 questions, and comply with the instructions. 



1. The unit of electrical pressure is the 



2. In a water system, current flow is measured in , 



but in an electrical system it is measured in 



3. The device shown in Figure 423 measures the of 



an electric current. 



4. A switch in an electric circuit corresponds to a . in 



a water circuit. 



5. Water pressure the farther away from the source 



one gets. 



6. A faucet in a water system 

 corresponds to a in an elec- 

 trical system. 



7. The reading of the electric 

 meter dials shown in Figure 424 

 is kilowatt hours. 



8. Ordinary house electrical 

 circuits operate on of elec- 

 trical pressure. 



9. To measure the current 

 flow in an electric circuit an 



is used. Central Scientific Company 



10. Electrical power is meas- Frc . 423 

 ured in , 



11. The consumption of electrical energy is measured in 



12. The unit of electrical resistance is 



10.000 



1.000 



100 



FIG. 424 



13. The resistance of an electric lamp is 220 ohms. If 

 it is used on 110 volts the current needed is 



14. A certain electric heater 

 uses five amperes of current 

 when connected to the 110-volt 

 line. The resistance of the heater 

 is 



15. The resistance of a coil of 

 wire is sixty ohms. What volt- 

 age is needed to run ten amperes 

 of current through it? 



16. The device shown in Fig- 

 ure 425 is used to measure the 

 of an electric current. 



17. Assume that the meter 

 reading in Figure 424 was taken 

 in a certain home at the begin- 

 ning of a month and the reading of the meter shown in 

 Figure 416 at the end of the month. Find the number of 

 kilowatt hours of electrical energy consumed during the 

 month and the monthly bill at the rate of ten cents per 

 kilowatt hour. 



Central Scientific Company 



FIG. 425 



SUPPLEMENTARY MATERIALS 



Reading suggestions 



Darrow, Masters of Science and Invention (Har- 



court) 

 Darrow, Boys' Own Book of Great Inventions (Mac- 



millan) 

 Darrow, Boys' Own Book of Science (Macmillan) 



Gibson, Romance of Modern Electricity (Lippincott) 

 Morgan, The Boy Electrician (Lothrop) 

 Seaver, The American Boy's Book of Electricity (Me- 



Kay) 

 Jones, The Life Story of Thomas Alva Edison (Gros- 



set) 



