Hollow Sphere
A hollow sphere is what is left of a sphere with radius [latex]r_{\scriptsize{2}}[/latex], when a sphere with radius [latex]r_{\scriptsize{1}}[/latex] has been removed from it, the two spheres having the same centre and [latex]r_{\scriptsize{1}}[/latex] < [latex]r_{\scriptsize{2}}[/latex].
Formulas
The volume V of a hollow ball is:[latex]V = \dfrac{4\pi (r_{\scriptsize{2}}^3~ - ~r_{\scriptsize{1}}^3)}{3}[/latex]