The government right now is siphoning off huge amounts of job creating capital from the private sector into government coffers to fund an unbalanced budget. The government is a black hole. I therefore vote with the professor and go with gravity.
For those who must siphon a liquid using a hose, if you don’t want the fluid about to be siphoned getting in your mouth, fill the hose with water, first, then make a crimp near the end about to be placed in the target liquid and empty that short section of the hose, plug the other end so the water remains in the hose from the crimp to the plug; push the short length into the target liquid then release the plug ... gravity will pull the water out, creating a suction of the target liquid which will flow through the vacated hose where a suction vacuum has been created.
Oh, I don't know. The government sucks, does it not? Thus pressure might be the driving force in that case.
Sucks, don’t it.