The Greedy Cup Has Become Even More Devious

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[DumbleSnore]

If anyone else was curious why the tube in the devious cup has to go all the way around the edge before it goes back down, it's to help prevent a moderately filled cup from draining when tilted.

[thesparklingsalt]

I've made Pythagoras coffee mug few years ago on 3d printer. The hole was hidden under the groove near the bottom.
Colleagues were pissed

[WhIteNErd]

I love how this guy always finds a way to involve his vacuum box in almost every video he made.

[HeeminGaminStation]

I have had a syphon explained to me like 12 times by friends, parents and teachers and it only sticks for like 3 seconds... but after watching this video with helpful visuals and thoughtful explanations I can comfortably say and I'm pretty sure it's devil magic.

[greatPretender]

If someone ever handed me a 3D printed cup, I would immediately think "this is devious"

Thanks everyone, I could not have imagined this

[R.J._Lewis]

My favorite part of the greedy cup is that it can be defeated by just putting a finger over the hole. If you start out with your finger over the hole before filling it, the air pressure keeps the wine out. If you realize too late and fill your cup too full, you just plug it. I've spilled enough wine on myself over the years that this wouldn't even phase me.

[jaypaymemonay]

The new cup is pretty good but it could be a lot better. hide the hole at the bottom by instead spreading it out as a thin ring at the base of the cup, with a slight overhang to hide it from view when viewed from above, and make the glass a little taller and more narrow so that you limit the angle that you can look down into the cup with. then you really are unlikely to notice it has a hole in it

[SomeoneCommenting]

You can easily make it with normal pottery and ceramic if you embed a small piece of copper or steel tube inside, bent in the right way. Disguise the hole inside at the bottom of the container as much as possible, maybe with the glaze coloring or some fancy shape, and people will never guess.

[nameismyname]

Glad to know that Pythagoras never thought of just smaller cups

[OC]

Perhaps Pythagoras could make it like the Devious cup but put the center piece as a warning of "don't go past this point".

[ninakircher]

Please remember that 3D printed objects are not foodsafe

[AverytheCubanAmerican]

I always kind of figured siphons worked by way of gravity and the fact that water wants to run downhill. Since the outlet of the hose, tube or whatever has to be lower than the level of the body of water you are siphoning from, that made the most sense to me. Give water a path to go downhill and that's where it will go. As far as how it can go up and over the edge of a container, I would say that has to do with momentum. In order for a siphon to work, the outlet has to be lower than the level of the water which gives it the momentum to make it up over the edge.

This is neat! Having played with siphons since I was a kid, it is interesting to see the scientific explanations. Making the walls thin and putting the siphon in the handle of a mug would be even more elegant for this. Actually usable. Also to make it really devious, make the hole at the bottom such that it can't be plugged with a finger.

[rcketplumber]

Easily done with a wax form for the channel, then mold clay around that. Dry it, bake out the wax, then fire as normal- all feasible with 500BC technology.

[OceanBagel]

This cup is still manufacturable through traditional subtractive manufacturing, although probably not as one solid piece. You would need to make three separate pieces and then assemble them together, but with good enough machining, you can still make it look like it's one solid piece once it's assembled.

[SupremeLeaderKimJong-un]

It starts with gravity pulling the liquid down from the top of the bend of the siphon. Once that starts the movement, the moving liquid has a lower pressure than the stationary liquid (Bernoulli's Principle) and the higher pressure/stationary liquid moves into the lower pressure/moving liquid area. It then keeps moving and falls out the other end of the siphon. More liquid moving through the siphon keeps Bernoulli's Principle going until you run out of liquid in the cup. I'm pretty sure people made much more complex things in the past without 3D printers. What they didn't have, was a 3D printer sponsor. Thank you, comrade Action Lab, very cool. I will prank US and South officials with these

[garviere]

What wasn't mentioned clearly is one of the most important contributing factors to how a syphon works which is vacuum. Gravity starts it off by pulling down on the liquid in the exit pipe but it is vacuum which draws the liquid up the entry side of the pipe. This is why to start a syphon off you have to suck on the exit end of the pipe to draw enough liquid for the gravity to get a purchase on it and start it moving.

So the way the Pye' cup works is the overflowing liquid fills up the space between the top of the down tube and the walls of the outer tube thus sealing the out chamber, as it goes down the exit tube pulled by gravity, it starts of the syphon by creating a vacuum in the exit tube and the now connected by seal entry tube.
Because the main bowl is higher than the end of the exit tube there is sufficient weight in the liquid going out to out weigh the smaller amount of liquid being pulled up by the vacuum enabling the cup to be fully emptied.

If the end of exit tube was higher than the bottom of the recepticle then there would not be enough weight in the exiting liquid to overcome the gravity of the entering liquid so one would cancel the other and liquid would just sit in both tubes going nowhere.

You can test this with two containers and flexible a tube. Fill one with liquid and place one end of the tube it (I know, basic syphoning, but just in case there are some people who have never done this) then suck on the other end of the tube (only use a drinkable liquid for this as you will probably ingest some) as soon as the liquid starts to run into your mouth hold the end of the tube lower than the glass, say off the edge of a table, into the other container, it will run freely, but as soon as you lift the end of the exit tube to near the height of the upper glass or container, the flow will slow and as you lift higher and eventually stop.

If there is still enough liquid in the exit side of the pipe and you lower it back to the other container it will self start, if there is not enough liquid in the exit side to out weigh the liquid in the entry side it will not self start.

Added to these factors though (gravity and vacuum) as mentioned in the video, you also have surface tension and friction which could effect how readily the syphoning process will self start depending on the size of the tube, type of liquid such as viscocity and strength of surface tension.

Hope this helps a little.

[westonding]

Let’s acknowledge James’s ability to Macguyver anything in a vacuum chamber! Genius explanations of the siphon effect! I did not realize it was a combination of effects!

[eve_squared]

You could easily have made that cup with clay and a tin wire, simply wait for the cup to dry and fire it and all the tin will melt out. It might even be easier than making the original. They probably would have used lead for it's abundancy.

[vdrhussar]

"Hey, look, a cup with A HOLE IN THE MIDDLE, not even a little bit suspicious hmm"

[robotnoir]

At the risk of stating the obvious... if you simply whack a handle on the cup, it's the perfect shape to hide the plumbing inside... which means you no longer need to have "suspiciously thick" walls on your cup. I've got a 3D printer and I've made this. Pity I cant post photos in the comments, coz you might like it. Anyway, I call it the "Pythagorean Mug".

(While we're on the topic... that single hole in the bottom is a design-flaw, coz people quickly look under the cup, understand what is happening, and put their finger over it. What you really want is, inside the base of the cup, you split the flow into six different pipes, and have them split up and drain out from around the edges of the base, instead of one hole in the middle. This results in your victims hilariously trying to plug the leak with their fingers, but quickly running out of fingers, with the liquid spilling up their sleeves for maximum annoyment.)