FACTS ABOUT WATER 267 



Experiment to Show Water Pressure. Heat a piece of glass 

 tubing until it is soft. Draw it out to a small jet. Attach one end 

 of the jet to a rubber hose, and place the other end in a dish of 

 water. Fill the tubing with water 

 by sucking the air out. Hold the 

 jet upright, allowing the dish of 

 water to be very much higher than 

 the jet. Raise and lower the dish 

 of water which represents a lake or FlG 169 



other source of water supply. 



What is th6 relation between the height of the source of water 

 supply and the jet? 



What is necessary that we may be supplied with water from 

 our faucets? 



QUESTIONS 



1. Why is it possible for a person to float in water? 



2. How much would you weigh in water if you were not trying to 

 float? 



.3. How much do a boat, engine, people, and material on a boat 

 weigh if the boat displaces 10,000 cubic feet of water? 



4. When you get into a rowboat how much more water must the 

 rowboat displace? Why is it easier to swim in salt water? 



5. Why will a life preserver which is guaranteed to hold up 

 20 pounds in water hold up a man weighing 240 pounds? 



6. Would a body a cubic foot in size weighing 125 pounds float 

 in water? 



7. Why is water more likely to enter the ear during a deep dive 

 than during a shallow dive? 



8. What is the weight of a granite monument which has a base 

 10 feet square, a top 2 feet square, and is 25 feet in height? 



9. What would be the pressure on your body per square inch, 

 per square foot, on the entire number of square feet on the body, if 

 you were 10 feet under water? Refer to page 47. 



10. What would be the pressure on a body the size of your body 

 which went down with the steamship Titanic 4 miles below the 

 surface of the ocean? 



