One of my co-workers went to a conference in Greece, and came back with a present, of something which is very old, from 400 years B.C. or even earlier, but I'd never seen before. It's called the Pythagoras Cup and it has this strange bit sticking up in the middle. And the story is that this cup was invented by Pythagoras. The one that worked on right-angled triangles. He invented it so when he gave his students wine, that they all got the same amount and if somebody was greedy, that student got his comeuppance It behaves normally, until you get to this gold ring here, the one I am running my finger around, not the one one up here. And if you fill it above that, that's somewhere between these two, suddenly, all the liquid in the glass drains out and through a hole in the bottom. Of course, you can't see what's happening here, so I rushed off and bought a glass one so you can see what's happening. I asked Neil to demonstrate it You pour in the water, imagine it's wine, but if it was wine you couldn't see inside. And, as the level of wine rises, suddenly, if you were too greedy, it all dribbles out. "sound of water draining" And, it siphons out through the little tube in the centre. The way it works is that inside here there is a u-tube which has a small opening at the bottom. And as the liquid rises, the u-tube fills up and when it gets to the top, it siphons 'round and sucks the water out. I was really excited about this, and then when I was driving home, I wondered, what would happen if you filled it with mercury. Mercury is a very dense liquid. So I persuaded Neil to fill it with Mercury, and it works just as well with Mercury. And, what is interesting is that when you do it with water, the water on our glass Pythagoras Cup dribbles out at a sort of angle because water so-called 'wets' glass; it sticks to the glass. But with mercury, because it is denser, and it doesn't wet glass, it goes straight down. And makes quite a sort of spectacular pattern in the bottom of the dish. I then had a slightly strange idea: I wondered what would have happened if you put just a little mercury in and then filled the rest with water. And I predicted, because water is much less dense than mercury, that, in fact, you could fill the cup right to the top. So Neil obligingly tried it even though he was meant to be going on holiday and it works. You can fill the Pythagorus Cup right to the top if you put a bit of mercury at the bottom So what it happening is that the weight of the water is just not enough to force the mercury up inside the siphon. If you fill it completely with mercury, you have enough weight pushing down to make the siphon work. So the upshot is that if Pythagoras' students had been clever, they could've put some mercury in the bottom of the cup and filled it right to the top. The downside of course, is that they would have poisoned themselves. There were quite nice crystals that you could see formed in the surface of the metal. And there was this great lump of mercury at the bottom, solid. But Neil had quite a lot of difficulty getting it out at the end and it began to melt and so on. But that wasn't part of the experiment.
That's real genius right here.
"The downside is that they would have poisoned themselves"
Not if Pythagoras' students drank at the right angle
Pythagoras might have considered giving his students smaller cups.
It's like a toilet
That crazy hair and calm demeanor are just a little unsettling.
The cup has a YouTube in it! Brilliant!
When I tilt the cup (for drinking) to the wrong side, will the liquid also drain out? If so, was there a "drink from this side" mark on the cup.
I don't think that it was pythagoras purpose to punish greed. I rather think that he invented a wine bong.
I've got one of these! https://m.imgur.com/zY78fSO
......or... they could have plugged the hole in the bottom