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?
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?
On the matter of the doughnut: If you make them at home, you’re almost always just rolling a cylinder and then making it a circle. I have never actually punched a hole out of a doughnut. That would mess up the toroidal shape.
But also: So you’re saying a straw has 0 holes?
Maybe she’s not, but I am. An intact straw has zero holes. If you stick a pin in the side, it has one. If you stick a pin all the way through, it has two.
A strownut if you will
I would eat that
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?
No, topologically there would be no holes until the moment of contact. This is the same as there being no hole when drilling through from only one side until the surface on the opposing side is broken.
Yes, but topologists can’t tell a doughnut from a coffee cup so they’re clearly insane.
So how does one “dig a hole?” Straight to China? Or whatever is opposite of you?
Topologically, yes. Buy you could also go down a bit, make a lateral tunnel, then pop back up.
So what you are saying is, if I dig a hole that doesn’t go anywhere, then that’s not really a hole?
In topology, yes. It must go through to count.
That’s fascinating. So most of what I would call “holes” are what, in topographical terms, hollows? Depressions?
Not only that, but if you pinch it in the middle until the passage closes, could it still be called just one hole?
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?
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
You just blew my mind. Thanks.
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.
By that argument your mouth is a continuation of your asshole… No offense.
I mean… yeah
Some people haven’t realized almost all animals are just tubes with various fancy shit glued on.
Edit: including humans
Or put biologically, virtually all fauna are just various advanced forms of flatworm.
IIRC humans have 7 holes topologically (assuming both vsauce and my memory are correct). I’m not sure how many a flatworm would have, but I bet you could group animals by number of holes topologically, which might be interesting.
Flatworms have a single opening that leads to a branching cavity (an incomplete digestive system). This means that the single opening is for both ingesting nutrients and expelling waste. While your mouth may be attached to your anus via the alimentary canal, I think it beats the hell out of having one multi-purpose opening, imho.
Right, technically a human only has 1 hole for ingesting nutrients and expelling waste as well though, assuming you are talking about the mouth and anus. Does a flatworm have any other through holes though e.g. nostrils or tear ducts? I have no idea what the biology of a flatworm is haha.
Two ears, mouth/anus/nostrils, urethra, optionally vagina. That’s 5…what else, eye sockets?
I guess we all are talking out of our asses, then…
Indeed, and when you kiss someone you are making one big hole connected by two assholes.
Given the amount of people I know who are always full of shit, I’d buy that
For normal people asshole would be continuation from mouth, but I don’t judge. You do you!
I assume that’s how OP’s debate of how many holes a human had ended up being about straws: someone argued that the mouth and the anus are just one hole
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’.
A straw does? What are you, the straw police?
Stick your finger through a donut, does it go in one side and out the other?
Giggidy.
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.
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.
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
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.
No, I´ll be puzzled for a second and then think you are making a joke.
I was also thinking zero. I picture a straw as a rectangular piece of material that’s been curled to form a cylinder, and in my mind that rectangle has no holes in it. I was confused when I saw that the options were only one or two.
As far as 2D topology is concerned the number of holes increase when you glue the edges of the rectangle together.
Though in that case you’re basically counting how many boundaries the surface has, which for a straw is 2 distinct circles.
A cup is essentially a self-contained hole that we pour stuff in, but if I say there’s a hole in my cup you’d know what I meant
From a topology perspective, a cup does not have a hole. A mug does, but its the hole that the handle makes, not the area containing liquid.
I see a lot of folks referencing topology, but clearly topology is not a particularly good go-to for how to talk about holes.
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From a topological perspective, a hole in the ground isn’t a hole… But you can still fall into it.
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From a topological perspective, a hole in your logic isn’t a hole – but you can still have one.
Clearly we’re talking linguistically, not topologically.
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Does a doughnut have two holes?
Because a straw is just an elongated doughnut.
So is a coffee mug.
Are we considering it 3D then? I thought we’d be thinking of it as a 2D surface (which, for the record, has got 2 holes).
A hollow cylinder has a single hole, with two openings. A hole can be open on one end only (e.g., a well is a hole in the ground), or it can have multiple openings (e.g., a straw has a hole with two openings).
If one cannot immediately tell whether two openings are connected to one another, then one assumes they are not; e.g., if you see a well in Florida you don’t assume it is the opening of a hole that extends to connect to another opening in Australia.
Not a native speaker, but doesn’t “hole” refer to an opening? The structure which connects two openings, but is itself not connected to the outside would be called cave, or tunnel.
It usually does, however, there are cases where a hole can have two openings. For example, there’s a saying/idiom about digging a hole through the earth and ending up in china/australia/etc. It would be confusing to say that you “dug two holes” to China, you would only say that you “dug a hole” to China. “Tunnel” is definitely more precise here, though it would be odd to refer to the openings in a drinking straw as a “tunnel”
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.
Continuing on the innuendo: topologically a vagina is not a hole, but a butthole is.
You could argue that a hole is an entrance to a wider space. A door or window is a hole to a room. If you want to know the number of holes in a room, you would at least have to include all the doors and windows.
In this sense, the straw doesn’t have a hole at all.
Or maybe it is just one hole.
Did not expect to learn that a butthole is topologically a real hole but I am here for it
I think the solution here is to have a way to measure the tightness of a hole (of which something can be inserted)
- A straw is a continuous surface without any holes.
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.
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.
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.
No.
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.
One. Imagine a cube of steel. Now you take a drill and you drill an hole into this cube. Now you saw around that hole so it has a wall thickness of 1mm. Now you have a straw made out of steel and you’ve drilled only one hole.
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
It’s one hole. Imagine a solid cylinder, how many times do you need to go through it to make it a straw? Only once :)
