Water Power 77 



SUMMARY 



Water exerts pressure in all directions and this pressure can 

 be measured. 



Water, fuel and wind provide most of the energy used by 

 man in carrying on the activities of modern life. 



There exists in the United States a vast amount of un- 

 developed water power. 



The principal kinds of water wheels are the over-shot, the 

 breast, the under-shot, the turbine and the Pelton. 



The turbine wheel is well adapted for use under a great 

 variety of conditions. 



The Pelton wheel is well adapted for use where there is a 

 limited amount of water having a high fall. 



A foot pound is the amount of work required to lift one 

 pound a distance of one foot. 



Energy is measured in terms of foot pounds of work. 



Power is the rate of doing work. 



A horsepower is a unit of measure of power and is equivalent 

 to 33,000 foot pounds of work per minute. 



Dams of great size are constructed for the conservation of 

 water, for power, for irrigation and for other uses. 



FACT AND THOUGHT QUESTIONS 



1. How can water pressure be measured? 



2. What forces provide most of the energy used by man? 



3. Under what conditions will a small stream provide considerable power? 



4. Will a stream supply more power by dropping to a fixed lower level 

 in one fall, or by gaining that level in a series of rapids? 



5. What is a dam ? Describe one you have seen. For what purpose was 

 it built? 



6. Why are dams thicker at the base than at the top? 



7. How may the opening of a water faucet downstairs affect the water 

 flow from an upstairs faucet? Why? 



8. Describe the effect of (a) drought and (b) freezing on water power. 



9. Mention various kinds of wheels that utilize the energy of falling 

 water. 



10. Describe the turbine. To what conditions is it well adapted? 



11. Describe the Pelton wheel. How is water applied to it? 



12. Define: (a) foot pound; (b) horsepower. 



