THE OCEAN OF AIR 



FIG. 14 



In your notebook 1 record the 

 notes of this experiment and 

 complete the statements below. 



On the up stroke the piston 



valve is (open, closed) 



and the foot valve is . 



The pressure on the surface of 

 the water in the jar or well is 



per square inch. As the 



piston rises, the pressure in the 



cylinder is , thus allowing 



the on the water in the jar 



or well to , 



Copy the drawing shown in 

 Figure 15 and place the valves 

 as they would appear on the 

 down-stroke of the piston. 



Experiment 6. What causes 

 a siphon to work? 



Connect two pieces of glass 

 tubing about ten inches in 

 length with a twelve-inch sec- 

 tion of rubber tubing to form a 

 siphon. Fill the siphon with 

 water and pinch the rubber at 

 the top while you insert each 

 glass tube in a bottle of water 

 as shown in Figure 16. Grasp 

 one bottle in each hand and by shifting the levels of the 

 bottles study the action of the siphon. 



Record the notes of this experiment in your notebook 2 

 and write the completions of the statements 

 given below. 

 The siphon does not flow when the bottles 



are The water always flows from the 



level to the level. The pressure of the 



air on the water in each bottle is pounds 



per square inch. The water in the arm of 



the siphon weighs the more. This causes the 



water always to flow the short arm and 



j the long arm. The liquid in the siphon may 



be made to run faster by 



Experiment 7. How is a bicycle pump 

 constructed ? 



Secure a bicycle or automobile tire pump and 

 take it apart. Study the construction of the 

 piston carefully. 



In your notebook 3 make a cross section draw- 

 ing showing the construction of the pump, 

 record the notes of the experiment, and com- 

 plete the statements below. 



Tjie air gets into the pump through 



The piston is made airtight by means of a 



which presses tightly against the walls of the cylinder on 



the of the piston but allows the air to on the 



stroke. 



Experiment's. jHow does air get into the lungs? 



Close the top end of a lantern globe tightly with a stop- 

 per cut from beaver board. Through the stopper drill a 

 small hole for a piece of glass tubing about six inches 



1 See accompanying workbook, p. 5. 



2 See accompanying workbook, p. S. 

 'See accompanying workbook, p. 6. 



FIG. 15 



in length. To one end of the glass tube attach a toy balloon 

 by winding the neck with many turns of thread. This 

 connection should be airtight. Place the glass tube through 

 the hole in the stopper in such a way that the balloon will 

 hang inside the lantern globe. Now stretch a piece of toy 

 balloon or old auto tire inner tube tightly over the bottom 

 of the globe and secure it with string. The lantern globe 

 represents the upper chest cav- 

 ity, the balloon a lung, and the 

 rubber across the bottom the 

 diaphragm. Push the diaphragm 

 up into the chest cavity. Pull the 

 rubber diaphragm down. 



In your notebook, record the 

 notes of this experiment and 

 complete the statements given 

 below. 



When the diaphragm is ex- 

 panded the in the lower 



chest cavity is reduced and . . 



is forced into the . Exhal- 

 ing is accomplished by the 



diaphragm when air is forced 

 of the 



FIG. 16 



OTHER INVESTIGATIONS WHICH YOU CAN MAKE 



1. In your notebook list as many uses of the vacuum as 

 you can and explain how each is applied. 



2. Make an investigation of the construction and opera- 

 tion of a vacuum cleaner and record the notes in your 

 notebook. 



READINGS WHICH WILL HELP ANSWER THE 

 PROBLEM QUESTIONS 



How long have pumps been known? Mention of 

 them is found in the writings of the ancient Greeks, 

 several hundred years before the birth of Christ. The 

 force pump was probably invented by Ctesibius, a 

 Greek, who lived in the city of Alexandria in Egypt. 

 This pump was used in quenching fires ; modern fire 

 fighting apparatus has a history. During the Middle 

 Ages pumps were in common use for raising water 

 from wells and from rivers for purposes of irrigation 

 and general use. In fact, it was by observing a pump 

 that Galileo, an Italian scientist, was led to the dis- 

 covery of the barometer. He noticed that a lift pump 

 could not be used if the 

 well was much more than 

 thirty feet deep. 



What are pumps used 

 for in modern life? They 

 are used on the farm and 

 in small towns for secur- 

 ing water from wells. In 

 many cities the provision 

 of an adequate supply of , 

 water would be impos- 

 sible if pumps were not 

 used. Industries use them 

 for pumping water or 

 other liquids such as 

 the brine in refrigerating 



FIG. 17, LIFT PUMP 



