Volume of Sphere Formula Derivation
Volume of sphere formula can be derived using the following methods:
- Using Integration
- Using Archimedes Relationship between Cylinder, Cone and Sphere
Let’s discuss these methods in detail as follows:
Volume of Sphere Using Integration
Using the integration approach, we can simply calculate the volume of a sphere.
Suppose the sphere’s volume is made up of a series of thin circular discs stacked one on top of the other, as drawn in the diagram above. Each thin disc has a radius of r and a thickness of dy that is y distance from the x-axis.
Let the volume of a disc be dV. The value of dV is given by,
dV = (πr2)dy
Thus, dV = π (R2 – y2)dy
The total volume of the sphere will be the sum of volumes of all these small discs. The required value can be obtained by integrating the expression from limit -R to R.
So, the volume of sphere becomes,
V = [Tex]\int_{y=-R}^{y=R} dV [/Tex]
⇒ V = [Tex]\int_{y=-R}^{y=R}π(R^2 – y^2)dy [/Tex]
⇒ V = [Tex]\pi|(R^2y – \frac{y^3}{3})dy|_{y=-R}^{y=R} [/Tex]
⇒ V = [Tex]\pi \left[R^3-\frac{R^3}{3}-(-R^3+\frac{R^3}{3})\right] [/Tex]
⇒ V = [Tex]\pi \left[2R^3-\frac{2R^3}{3}\right] [/Tex]
⇒ V = [Tex]\frac{4}{3}\pi R^3 [/Tex]
Thus, the formula for volume of sphere is derived.
Volume of Sphere Using Archimedes Relations
As Archimedes has already proved, if a cone, a sphere, and a cylinder have the same radius r and the same height, their volumes are in the ratio of 1:2:3.
Therefore we can say:
Volume of Cylinder = Volume of Cone + Volume of Sphere
Thus, Volume of Sphere = Volume of Cylinder – Volume of Cone
As we know, that volume of cylinder = πr2h and volume of cone = (1/3)πr2h
Substituting these values into the equation, we get:
Volume of Sphere = πr2h – (1/3)πr2h = (2/3)πr2h
We assume that the height of the cylinder equals the diameter of the sphere, which is 2r. Thus:
Volume of sphere is (2/3)πr2h = (2/3)πr2(2r) = (4/3)πr3
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Volume of a Sphere
Volume of a Sphere is the amount of liquid a sphere can hold. Volume of Sphere formula is given as 4/3πr3. It is the space occupied by a sphere in 3-dimensional space. It is measured in unit3 i.e. m3, cm3, etc. A sphere is a three-dimensional solid object with a round form in geometry.
The volume of the sphere is the total space occupied by the surface of the sphere and it is proportional to the cube of the radius of the sphere. In this article, we will learn about Volume of Sphere, Volume of Sphere Formula, Volume of Sphere Formula Examples, and others in detail.
Table of Content
- What is Volume of a Sphere?
- Volume of Sphere Formula
- Volume of a Solid Sphere
- Volume of a Hollow Sphere
- Volume of Sphere Formula Derivation
- How to Calculate Volume of Sphere?