THE ATMOSPHERE 



57 



Fill a bottle full of water, and with a rubber stopper 

 carrying a long glass tube close the bottle air-tight, with 

 water in the tube above the stopper. Attempt to suck water 

 out of the bottle through the tube, and explain the results. 

 Repeat the experiment, but with the bottle only partly 

 filled with water, i.e., with some air in the bottle. Why are 

 the results so different? 



4. Follow very closely the teacher's explanation of the 

 action of both lift pumps and force pumps as these are 

 illustrated by use of glass models, or by drawings at the 

 blackboard. Then by the use of draw- 



z> 



ings on your papers write brief descrip- 

 tions of both kinds of pumps. 



5. From explanations of the action 

 of air pumps by the teacher, based on 

 the operation of an air pump or on 

 drawings at the board, write a descrip- 

 tion of your OWTL of their construction 

 and operation. (Use any drawings that 

 may aid in making your description 

 brief and clear.) 



6. Fill with water a glass tube bent 

 for use as a siphon (si'fon), one arm of 

 which is only a little longer than the 

 other. Holding a finger over one end 

 so that the water will not run out of 

 the tube, put the short arm of the 

 siphon down into a tumbler filled with 

 water, and then remove the finger. Infer (a) what causes 

 the water to rise in the tube above the tumbler top; 



FIG. 22. 

 The 



arms of the siphon 

 are from the surfaces 

 of the liquids at A 

 and at D to the high- 

 est part of the siphon 



