Question

Figure 9 shows a setup used by a student to investigate how a siphon works.

1. State what would be observed when the student sucks the tube at point A and releases it. 
2. Explain the observation above.

Answer 1

1. Upon sucking, the liquid flows in the delivery tube but stops on releasing because the sucking force is withdrawn/ Liquid flows because of the pressure difference
    
2. The liquid fails to flow on release because there is no pressure difference to push the liquid up the tube without sucking/ the level of the container is above the liquid level.