Explaining Questions - PRESSURE

1.  Explain why divers must breathe out as they rise to the surface?
   
   ANSWER
   As the diver ascends from the bottom to the surface, the pressure exerted by water decreases. This decrease in pressure causes the volume of any gas in the diver’s lungs to increase if the diver does not compensate.
2. Describe carefully how you would use a siphon to remove the major part of the water contained in a large fixed tank, open at the top. Draw a diagram and use it to explain the action of the siphon.
   ANSWER
   
   
   EXPLANATION
   Water rises in the tube because it is pushed by atmospheric pressure. The force of gravity draws water through the long arm, and this maintains the low pressure that is established at the short arm. Once start, the siphon does not require addition energy to maintain water flowing out of the tank. The siphon will pull out large part of the water in a large, fixed tank.
3.  Use a diagram to describe how manometer can be used to measure the pressure of a gas at a gas-tap. .  CONTINUE READING