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.
Pass the hose to your friend and let him do it....because he’s just been standing there telling YOU how to do it....
Or you can get an ingeneous device called a jiggle siphon. Basically, the end you put in the higher tank has a wide spot that has a ball inside it that acts like a check valve. If you jiggle the hose a few times, it will let liquid into the tube, but not let it back out. After a few jiggles, there will be enough liquid in the tube to go over the U, start falling, and thus pulling vaccuum.
Walla, easiest way on the planet to drain a 5 gallon gas tank.
So would siphons work in a vacuum?
I knew a chick who could siphon a golf ball through a garden hose. Not sure if she was a physicist.
I nice trick I learned is to place two tubes into the tank to be siphoned and wrapping a cloth in a figure eight around the tubes. Below the cloth one tube should be long enough to reach as much liquid in the tank as needs siphoned while the other should be just long enough to enter the tank. Then push the rag into the tank opening trying to get the best seal that you can. Then blow into the “short” tube. I was amazed how well it worked.