What is the Concept of Volume?

  • Context: High School 
  • Thread starter Thread starter batballbat
  • Start date Start date
  • Tags Tags
    Concept Volume
Click For Summary

Discussion Overview

The discussion revolves around the concept of volume, particularly in relation to geometric shapes such as spheres and cylinders. Participants explore the implications of having holes in these shapes and the definitions of bounded solids in geometry.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion about whether a sphere with a hole has the same volume as a solid sphere, suggesting that a sufficiently small hole might not affect the fluid capacity.
  • Another participant questions the terminology used, noting that "sphere" typically refers to the surface and suggesting that the terms "sphere" and "ball" are being used interchangeably.
  • Some participants argue that a cylinder without a lid has the same volume as one with a lid, while others contend that physical objects like a cylindrical can do not have the same volume with and without a lid due to the volume of the lid itself.
  • A later reply points out that in mathematical terms, a solid cylinder's top has zero thickness, implying it has zero volume, which complicates the understanding of volume in idealized shapes.
  • There is a question about whether only bounded solids have volume, with a participant suggesting that the region defined by certain inequalities has the same volume regardless of whether the boundary is included.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definitions and implications of volume, as there are multiple competing views regarding the treatment of holes in shapes and the nature of bounded solids.

Contextual Notes

There are limitations in the discussion regarding the definitions of terms like "sphere" and "volume," as well as the assumptions about idealized shapes versus physical objects. The mathematical treatment of volume in relation to boundaries remains unresolved.

batballbat
Messages
127
Reaction score
0
i am having confusion with the concept of volume. Does a sphere with a hole have the same volume as the volume of a sphere? I think it doesent, but if the hole is sufficiently small, they would hold the same amount of fluid. Also the hollow space of sphere counts as its volume. Then why doesent a curved plane which covers some hollow space count as its volume. please give me a detailed definition of volume
 
Mathematics news on Phys.org
I'm not entirely sure what you're talking about here. What do you mean by "why doesent a curved plane which covers some hollow space count as its volume?"

Part of the problem seems to be that you're using strange terminology. Generally, the term "sphere" refers refers to the surface of a ball, but you seem to be using "sphere" and "ball" interchangeably, and so I have no idea what a "hole in a sphere" is supposed to be. The notion of volume is an intuitive concept; if you want a "detailed" rigorous explanation, you need real analysis.
 
a cylinder without a lid has the same volume as a cylinder with lid. So it is not clear to me. Same for sphere
 
batballbat said:
a cylinder without a lid has the same volume as a cylinder with lid. So it is not clear to me. Same for sphere

And you just said it. A sphere with a "hole" has the same volume as one that doesn't.
 
batballbat said:
a cylinder without a lid has the same volume as a cylinder with lid. So it is not clear to me. Same for sphere
A cylindrical can, for example, does NOT have the same volume with and without the lid because these are actual physical things and both can and lid have volume.

But the mathematical, ideal, solid has boundary with 0 thickness. The "top" of such a cylinder has 0 volume.
 
Last edited by a moderator:
what is the volume of a sphere with a hole? so in geometry only bounded solids have volume, am i correct?
 
batballbat said:
what is the volume of a sphere with a hole? so in geometry only bounded solids have volume, am i correct?

I think you need to be more precise in your descriptions. The region of 3 space defined by:

x2 + y2 + z2 < r2

has the same volume as

x2 + y2 + z2 ≤ r2

even though the first doesn't include the boundary, while the second does.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
5K
  • · Replies 50 ·
2
Replies
50
Views
8K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 29 ·
Replies
29
Views
3K
Replies
0
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 1 ·
Replies
1
Views
886
  • · Replies 23 ·
Replies
23
Views
3K
  • · Replies 36 ·
2
Replies
36
Views
7K