EXERCISE 50 



HOW DOES A SIPHON WORK? 



Materials. Rubber tube about 18 inches long; two jars or pans, one of which will hold 1 or 

 2 gallons of water. 



Directions. Two students should work together. Submerge the rubber tube in a jar of water 

 so that the tube will be filled completely. Close one end by pinching and withdraw that end from 

 the water, placing it in an empty jar with the end of the tube on the bottom of the empty jar. 

 Release the tube, observe, and explain what happens. Allow the tube to remain until the water 

 stops running. Compare the depth of the water in the two jars. What caused the water to run? 

 What caused the water to stop running? Write complete notes on what you did and observed, 

 and an explanation of the working of a siphon. 



Additional problems. Why will a siphon fail to work if any part of the siphon tube is over 33 feet 

 higher than the level of the water which is being siphoned ? 



How can you remove the stale water from a goldfish jar and introduce fresh water without in any way 

 disturbing the jar ? 



A jar of clear liquid has a scum on its top. How can you remove almost all of the liquid with the least 

 disturbance to the scum ? How can you start the siphon without submerging the entire tube in the liquid ? 



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