The mathematically correct answer is 1 hole . A straw is topologically the product of a circle, which has 1 hole, and an interval, which has 0 holes. So the straw has 1 hole. ... Intuitively, we can agree a circle has 1 hole–the simple closed curve contains a 2-dimensional hole inside of it.
How many holes does a donut have?
Topologically, that would be the same as S1 × D, where D is a disc (imagine gluing a disc to each point around a circle). This is actually true since the disc can be deformed to an interval–just squash it to a diameter. The assertion is then that a donut “clearly” has one hole .
Does a donut have one or two holes?
So for any shape that is topologically a sphere, its Euler number is 2; for a donut-like torus, it’s 0; for a flat disk it’s 1; and so on. Each surface has its own Euler number. ... A hollow torus can be cut twice — once around the tube and then along the resulting cylinder — so by this definition, it has two holes .
Does a straw have 1 hole or 2 Reddit?
“ An ideal straw has no holes . It is a pipe. “If it had a hole, it would leak,” mused one commenter. “A straw with a hole is a defect.”
What is considered a hole?
A hole is an opening in or through a particular medium, usually a solid body . ... Depending on the material and the placement, a hole may be an indentation in a surface (such as a hole in the ground), or may pass completely through that surface (such as a hole created by a hole puncher in a piece of paper).
Does a straw have 2 holes or 1 type questions?
“An ideal straw has no holes . It is a pipe. If it had a hole, it would leak.” “‘Technically’ a straw has one hole but ‘technically’ it does not.
How many holes are in pants?
A pair of pants is any surface that is homeomorphic to a sphere with three holes , which formally is the result of removing from the sphere three open disks with pairwise disjoint closures.
Does a paper towel roll have 1 or 2 holes?
One Hole: The argument for the answer “one hole” is that a roll of paper towels (or toilet paper, straw, etc.) is that the object has one opening through the middle of it. ... Two Holes : This explanation makes more sense with things like rolls of paper towels/toilet paper.
Does a cylinder have two holes?
Two openings, one cavity . If you think of it as a cylinder, it’s two holes. If you think of it as thick block with a perimeter marginally larger than the hole it only has one hole.
Is a tunnel a hole?
is that hole is a hollow spot in a surface while tunnel is an underground or underwater passage.
Why is hole called hole?
Love had originally wanted to name the band Sweet Baby Crystal Powered by God, but opted for the name Hole instead. During an interview on Later... with Jools Holland, Love claimed the name for the band was partly inspired by a quote from Euripides’ Medea that read: “ There is a hole that pierces right through me. “
Does a bowl have a hole?
A bowl has no holes (genus 0), a coffee cup has one (through the handle – making it genus 1), a pair of spectacles (without the pieces of glass) has two holes (genus 2), and a pretzel can have three holes (genus 3).
Do straws have 2 holes?
“ An ideal straw has no holes . It is a pipe. If it had a hole, it would leak.” “‘Technically’ a straw has one hole but ‘technically’ it does not.
What shape is a straw?
A straw is the product of a circle and an interval; a topologist would denote this S1 × I, where S1 is usually thought of as the unit circle in the plane and I is the interval [0, L] (here L = the length of the straw).
How many holes does a torus have?
So the torus has two one-dimensional holes .
How many holes are in your brain?
Lobes of the brain
The cerebral hemispheres have distinct fissures, which divide the brain into lobes. Each hemisphere has 4 lobes : frontal, temporal, parietal, and occipital (Fig. 3). Each lobe may be divided, once again, into areas that serve very specific functions.
