Can we settle this: how many holes does a straw have?
At work we somehow landed on the topic of how many holes a human has, which then evolved into a heated discussion on the classic question of how many holes does a straw have.
I think it's two, but some people are convinced that it's one, which I just don't understand. What are your thoughts?
How many holes does a donut have?
Now make the donut higher. A lot higher. Now you have a donut-tunnel. Now make the walls thinner. Now shrink it. Now you have a straw.
One hole.
Take a sealed tin can. Punch a hole in it. Punch another hole in it. You now have one hole.
Now take that straw and tie a knot in the middle of it.
That doesn't change the topology though. Or at least you can't without it no longer being a straw.
A straw is the product of a circle and an interval. Either the knot doesn't fully seal the interval, meaning it's topology is maintained, or you completely seal the straw, changing it from 1 long interval to 2 separate intervals, changing the object entirely.
In this situation, the straw would not be completely sealed. It is clearly inefficient, but technically there exists a path for which there is a level of force that could applied that would make the straw function.
This seems overly reductionist to the point where I could just as easily describe my mouth and my anus as the same hole.
that is actually the case. there is an unimpeded path from your mouth to your anus
Yeah, that's a concept that gets covered extensively in anatomy, immunology, and microbiology. It's called "the donut model". This is not a joke. It clearly shows how your digestive system is exposed to the outside world, similar to skin. You can obviously see why this is important immunologically, since germs can just get into the mouth/butthole in a way that they can't penetrate skin.
It's one long hole.
Because they are the same hole. Welcome to topology
It's perfectly reductionist. You have defined our biology in exactly the same way medical texts do.
Now you're getting it!
Yes. It's called the gastrointestinal tract.
They did the math!
I understand geometrically they have the same number of holes but in my head straws still have two holes because they have an "inside" so both entrances to the inside have to be a hole.
That's because a straw has two more holes than a sphere.
Mathematically It's one. Think of a disk, like a CD, does it have one hole or two? One, right? Now imagine you can make it thicker, I.e. increase the height, and then reduce the outer radius... Making it progressively more straw-like. At what point does it stop having 1 hole and begin to have 2?
Topologically they're the same shape.
I'm sure Matt Parker has a video on this topic in YouTube. Here
The specific field is topology fyi
If I dig a hole, how many holes is it?
Holes in the hole? 0
Holes in the top layer of the ground? 1
Zero unless you reach Australia
Classic topology question. Absolutely one hole; it goes all the way through.
Of course, connotatively, two is a fine assessment, but not in topology.
How many holes does a donut have? Now just try to image the real difference between a straw and a donut. Is there one, aside from deliciousness?
Deliciousness here is only limited by bravery.
Taste. Edibility is relevant to bravery, not enjoyability.
That's nice but topology is quite removed from everyday language. A hole in the ground is a hole.
how many holes does a donut have? one. a straw is just a tall plastic donut.
two holes... smdh... kids these days
What if you tie a knot in the straw? Still one?
Just copying my response to another comment asking the same:
That doesn't change the topology though. Or at least you can't without it no longer being a straw.
A straw is the product of a circle and an interval. Either the knot doesn't fully seal the interval, meaning it's topology is maintained, or you completely seal the straw, changing it from 1 long interval to 2 separate intervals, changing the object entirely.
In this situation, the straw would not be completely sealed. It is clearly inefficient, but technically there exists a path for which there is a level of force that could applied that would make the straw function.
if it doesn't go all the way through anymore, is it even a hole? zero.
A straw is geometrically the same as a circular piece of paper with a z depth of zero and a hole in the middle. Because the z depth is zero there is only one hole. As you add thickness the one hole remains. Therefore, a straw has one hole.
It has two exits, one hole.
If you drill a hole in a block of wood you create one hole not two, note that whether or not the drill exits the opposite side, only one hole has been created despite differing numbers of exits.
What if you drill through a book?
You'll be banned from the bookstore
Is the book closed before and then being opened after? The state of the book matters (and possibly the pages!)
It's just one long hole.
yup, answer is 1
I believe the confusion lies in the word "holes" when you are thinking about openings or exits. Just my 2 cents.
Yes, I agree. "Hole" is poorly defined. This isn't a technical question about straws but a technical question about language.
That's the gist of practically all philosophical thought experiments.
When is a heap of sand no longer a heap? I dunno, define "heap" and there's your answer. It's not going to be a useful answer though because the rest of the world doesn't define the word with enough precision for the question to be meaningful in the first place. There is no authority on Earth that can do that. You can define the problem in precise mathematical terms but then it will NOT be the same thing as a plain-English "heap" and you'd be pulling a fast one if you acted like it was.
It's one, big long hole. If you drilled a hole through a board, do you say it's two holes?
Or it's 0 holes, as it's not cut out of something, but rather just formed that way meaning by strict dictionary definition, there are no "holes."
Yeah but if you used a board as a straw you’d look like an idiot.
1 'hole' if you can call it that. Imagine if the straw started life as a solid cylinder and you had to bore out the inside to turn it into a straw: if that were the case, you would drill 1 hole all the way through it.
Another analogy is a donut. Would you agree that a donut has just 1 hole? I would say yes. Now stretch that donut vertically untill you have a giant cylinder with a hole in the middle. That's basically now just a straw. The fact you stretched it doesn't increase the number of holes it has.
Imagine if the straw started life as a solid cylinder and you had to bore out the inside to turn it into a straw
This would mean a straw has a hole, yes. It would be like a donut indeed - donuts are first whole, then have the hole punched out of them. This meets a dictionary definition of a hole (a perforation). A subtractive process has removed an area, leaving a hole.
But straws aren't manufactured this way, their solid bits are additively formed around the empty area. I personally don't think this meets the definition.
Your topological argument is strong though - both a donut and straw share the same topological feature, but when we use these math abstractions, things can be a bit weird. For instance, a hollow torus (imagine a creme-filled donut that has not yet had its shell penetrated to fill it) has two holes. One might not expect this since it looks like it still only obviously has one, but the "inner torus" consisting of negative space (that represents the hollow) is itself a valid topological hole as well.
“This meets a dictionary definition of a hole.
But straws aren't manufactured this way, their solid bits are additively formed around the empty area. I personally don't think this meets the definition.”
By this logic, how I make a doughnut changes whether it has a hole.
If I make a long string of dough and then connect the ends together and cook it (a forming process) it doesn’t have a hole.
If I cut a hole in a dough disc and then cook (a perforation) it has a hole. Even though the final result is identical?
So as you begin to bore, that is one hole. But when you go through the other side, you have in fact made two holes. I think a donut can actually be thought of either as one hole or two holes, or more correctly; two holes that are the same hole.
Back to the straw; if you make another hole in the side of the straw half way up, would it still have one hole? Or two holes? Or three holes?
A bit like thinking of the human digestive tract, most of us would agree that your mouth is a different hole to your anus, but we agree that they are in two ends of the same system
But here's the thing. Take that doughnut and stretch it until it's a cube with two square cutouts in it. Stretch in some of the inner walls. Now you have a house, with a door and a window. Now: does the house have two holes - a door and a window - or does it have one hole?
Locally has two extrinsic holes, that is holes relative to things outside and inside the house, globally has one intrinsic hole. We say that the door is a hole respect to the wall no to the house itself. So both the door and the window are holes locally. But we never say the house has holes, we talk about walls and ceilings so globally that house has 1 hole. Another way of thinking it is that if the house can be deformed into a filled doughnut then it can be compressed to a circle and that's the definition of a 1-hole.
Topologically, still one
You just blew my mind. Thanks.
What if you bored from both ends of the cylinder until they meet in the middle?
There would be two holes until, at the moment of contact, it becomes one?
Does the method with which the straw shaft is created influence the number of holes it has?
One of course, what a weird conversation to have.
If you make the straw less long, it’s a donut. And a donut obviously has 1 hole. So a long donut only has one hole. Q.E.D
I didn’t expect all the other comments to also use donuts to explain this
one hole is going through the straw
No it's two holes
I’m more interested in humans. Is the mouth and anus two holes or one?
on average, seven. vsauce has a video on this
Poop. Beans. Here come the holes.
How many holes does a rubber band have? A donut?
Topologically a rubber band, a donut, and a straw have the same number of holes. The hole at either end of the straw is just a continuation of the same one hole.
None of them have holes, usually. A hole goes from the outside of a volume to the inside. Those are all intact tori.
Take that cylinder and stretch it until it's a cube with two square cutouts in it. Stretch in some of the inner walls. Now you have a house, with a door and a window. Now: does the house have two holes - a door and a window - or does it have one hole?
I disagree. A rubber band and a donut do not have an 'in' and 'out'.
Stick your finger through a donut, does it go in one side and out the other?
A straw's "in" and "out" are completely arbitrary. You can flip a straw either way and it'd still work.
Anything with a hole through it that isn't perfectly 2D could have a "in" and "out" side. Your rubber band your doughnut only don't have one because nobody ever thought to define one.
How far are you zooming in? I'd say there are basically infinite holes if you look at it at an atomic scale
as vsauce said "At small enough scales, 'How many holes does [an object] have?' becomes a meaningless question. Ultimately, [the object] isn't a solid thing that could even have holes. It's just a loose constellation of atoms and molecules."
That’s what she said
One
Its one
To settle this argument could you clarify if we're supposed to be considering the straw as a solid 3D object with a thickness, or as a curved 2D surface? The answer kind of depends on which you pick.
Found the CAD user
One long hole that goes all the way through the straw
It contains one hole. While it appears to have two holes, if both are closed, you get a hollow sphere, which has -1 hole.
A hole is an opening on (something), and a TUNNEL is an end that leads to a hole that leads to another hole and to another end. Therefore, it has zero holes, but one (very small) tunnel.
A tunnel is also just a hole. A long tunnel is clearly a tunnel (through a mountain, for instance).
How short does the tunnel need to be, to no longer be called a tunnel?
20 meters is a tunnel.
5 meters is a passage.
1 meter is an arch.
5 centimeters is more like a doorframe?
5 millimeters is definitely a hole.
0.1 millimeter is a hole (like in a paper in a binder).
A tunnel is also just a hole.
That is like saying that the sky is just a bunch of colors. Or that an orange is a football. What you are missing here that most things can be COMPOSED (!) of (various) other things...
...unless you will reply with this with something like "That's right! We are just a ball of flesh!". Then eh.... *shrug
Your definition list was on point tho, I give you that.
A regular straw has zero holes. The central cavity, through which beverages flow, is not part of the straw, and hence it's endpoints are not holes in the straw.
I can't even understand the thinking that produces 2.
What about zero? If you start with a flat sheet of paper, it has zero holes, loop it around on itself, does that creat a hole?
It's just a flat plane with no holes curved around on itself.
By looping it on itself you've created a hole.
Ok how many holes does a Mobius strip have?
I mean, while I agree with the sentiment, I can understand the 2 holes side of the argument.
If you want to break it all down and super simplify it, you could argue that your digestive tract is a straw, so why do you differentiate between the start hole and the end hole?
I will not take that position though, because as I said, it’s over simplified.
I would argue that because a human is more complex than a straw, we need to differentiate between the holes we have.
A straw is simple. One straight hole all the way through. Maybe it has lots of curves but the ends of the straw are the same.
For a human, we have lots of curves to our "straw" but diffrent openings on each end.
I thought one hole intuitively, then I started thinking... what about those y shaped straws or medical hoses that split.... one hole? Two holes? Three?
A Y straw has 2 holes, according to topology.
If you want to learn more about topology, I think Vsauce's video "How many holes does a human have?" explains it pretty well
I came here to link that video
Define a "hole".
One common definition of a hole defines a hole specifically as the opening. If the definition applies only to the opening, this implies that the hole exists on a 2-dimensional plane. Despite the fact that the openings are connected along a tunnel, we don't care about the structure of a hole beyond the 'opening', we can ignore everything else. If we continue on that path, there are 2 visible holes on a straw.
I can't wait for Super AI to help humankind resolve these existential issues once and for all.
A straw has zero holes
Then how does the liquid go through it
Hopefully none, it won't work well if there are holes.
Relevant background music for your pondering. Fitting background music while you ponder
Physically or Metaphysically?
Relevant Vsauce video https://youtu.be/egEraZP9yXQ
Well, depends what you call a hole. Does a glass have a hole? Does a bottle have a hole?
If you said no to both, you mean a topological hole and a straw has one.
If you said yes to one or both of them, you mean a tight opening in which someting can be inserted (yes yes, innuendo). How tight an opening must be to be a hole is arbitrary and subjective, it depends on the person. In this case a straw has two holes.
I think the solution here is to have a way to measure the tightness of a hole (of which something can be inserted)
Maybe a cylinder
By the logic of most of the comments in here, does this mean most people are wrong when they say they are digging a hole???
Judging by what this video by Vsauce about how many holes a human has it should be one in a straw. A straw is basically just a long doughnut and there's one hole in those.
None. Colloquially, we use "hole" in all kinds of weird ways. As others have pointed out, topologically a straw is no different to a torus (donut) that clearly has one "hole"... but I'd like to focus instead on the linguistic definition of "hole", not the colloquial or mathematic definitions.
A hole can either mean:
i think we're not talking about 2. It seems to require some larger uniform structure or set of items in which an item is missing. 1 and 3 seem really similar to me: both seem to require some active removal of matter to qualify. All of these definitions point towards a subtractive process, where something of a larger whole (heh) is removed or absent.
Most straws, I'll venture a guess, are not manufactured solid and then bored out.. so I don't think it applies here. So I don't think a straw matches a fitting definition of "hole". A straw is created additively by assembling the "shell" by some means, not subtractively. Donuts, by comparison, had holes punched in them. A subtractive operation. Rubber bands have not had holes punched in them... they're additive. Not holes.
Similarly (because I see a lot of talk about buttholes and mouths here too), your esophagus and digestive tract (and veins and all kinds of other things) were formed in a similar additive manner, not by forming a mass of meat and boring through the passage, and thus would similarly not qualify as "holes" (in my opinion).
Matt Parker did quite a good video on this exact question: https://www.youtube.com/watch?v=ymF1bp-qrjU
Another video that should have been an article.
this the best answer
I think this depends on the semantic basis one uses for "hole".
1 hole: One might say there is a single hole in a straw. The logic there is that the straw is a cylinder, so the inner surface at the top is a part of the same surface at the bottom. In that sense, a hole itself is a kind of cylinder with a single connected surface. But this could be taken as problematic, since the same argument means that the straw itself is a hole, or at least that it is made up entirely of the exact same things a hole must have, and nothing else.
2 holes: Where that fails is if one instead assumes the more abstract sense of "hole". Consider the straw as a vessel with a volume -- with both ends plugged, it holds a substance. One can unplug either end and argue that it is a hole since the substance within is now open to the outside by way of that hole. In that sense, there are two abstract holes in a straw (abstract because the connection between both holes is ignored -- neither hole is taken to have any depth -- and each hole is an absence of material). Of course, due to physics, unplugging one end of the straw does not release the substance within if the other end is still plugged, but that holds no consequences for the logic of hole-as-absence-of-material.
0 holes: The argument could go further. One could try and solve this by considering other objects and how we think about "hole" in those contexts.
How many holes are in a bucket? If it's a perfectly undamaged bucket, people would likely be arguing between two different values: in one sense, the bucket has a single hole, because there is an opening at the top. However, using the same logic that straws have a single hole, the bucket in fact is made of its hole, and it seems silly to say the bucket itself is a hole.
If one goes with hole-as-absence-of-material, then there's a single hole in an undamaged bucket, but the bucket isn't made up of hole.
Further still, one might argue instead that an undamaged bucket has no holes. Why? Because a liquid in such a bucket will not leak out of anywhere. The bucket is effectively a round piece of material formed into a shape, and that material itself contains no holes in an undamaged bucket.
Using that logic with the straw, an undamaged straw might actually be claimed to have no holes -- but how? We've all likely used a straw that was bent or damaged and is less useful as a straw because pressure escapes from somewhere between the ends. Such a straw could be said to have a hole in it. There, "hole" has some aspect of brokenness being taken as part of its meaning. If the pressure-vessel part of the straw functions correctly, then it has no holes.
In popular culture: Consider the following lyric from Funkadelic: "What is a pipe but a pole with a hole in it? A pole is a pipe with no hole in it."
There, the band has clearly relied on the 1-hole analysis of a pipe (taken to be relevant to the straw discussion since it seems uncontroversial to claim that a straw is a small pipe). Had they said "no holes in it", the suggestion would have been that the band agrees with the abstract hole-as-absence-of-material sense. Similarly, it does not appear that the band thinks there are no holes in a pipe; in fact, that would be directly contradictory to their statement. But no logic is given directly for that choice in the song; one must extrapolate their position by context.
tl;dr A straw could be taken to have 0, 1, or 2 holes in it depending on the semantic sense of "hole" one selects. I need to think about this more like I need a hole in the head, but I also don't know how many of those I have.
What about a tank that has one input and one output hole, technically much like a straw? This is why I call the edges of a straw a hole, so straw has two holes.
Or, what about drinking straws with more than one succy pipe?
A straw with 3 openings would have 2 holes.
The answer depends on the context. Topologically, it's one. I personally like zero. If I say "There's a hole in my straw!" You'll not think all straws have holes. You'll think there's something wrong with it.
If you say "There's a hole in my straw" I think it's always implied you're talking about an unexpected hole. You can also say "There's a hole in my sweater/pasta strainer/etc" and people would get you're talking about a hole that is not supposed to be there. Straws are the same. They have one hole and you'd be unhappy if another appeared.
To be fair, I think shirts already have holes, but if I said "there's a hole in my shirt" you'd think there was an EXTRA hole
By the logic of most of the comments in here, does this mean most people are wrong when they say they are digging a hole???
I'm Diggy Diggy crater