214 Our Surroundings 



9. What is meant by an electric current? What must be considered in 

 measuring its effect? 



10. Why do lightning rods extend into the ground? Why should the 

 ground be moist? 



11. Describe a storage cell. 



12. Would you use a cell if you needed a great amount of electricity? 



13. Name several common uses of electric cells or batteries. 



14. What kind of cell may be used for a doorbell? For an automobile? 



15. For what are each of the following used: Ohm, volt, ampere, watt? 



16. Is it true or false that a modern steel building does not need lightning 

 rods? 



PROJECTS 



1. Make an electroscope and test it. 



2. Make a simple electric cell. 



3. Secure an old automobile battery, take it apart and examine its con- 

 struction. Make labeled sketches showing the construction. 



OUTDOOR OBSERVATION 



1. Record your observations of lightning during a night thunderstorm. 

 Study the effects of a lightning stroke on a tree, if possible. 



2. During a walk about town observe and record different uses of elec- 

 tricity. 



REFERENCES 



Practical Electricity for Beginners Willoughby 



Romance of Modern Electricity Gibson 



