Hi Terry,

Question; If you were to fill a bucket with water and then place a rubber pipe in it and suck the water through the pipe using your mouth, how much effort would you need to put in ?

Then place a pair of mole grips on the pipe and swish the pipe. Now try again to suck the water through the pipe, What happens?

Lastly, drill or cut a small hole in the rubber pipe near the end you are sucking from and then repeat the test once more.

Mark