 # Spherical shell

In geometry, a spherical shell is a generalization of an annulus to three dimensions. It is the region of a ball between two concentric spheres of differing radii.

## Volume

The volume of a spherical shell is the difference between the enclosed volume of the outer sphere and the enclosed volume of the inner sphere:

$V={\frac {4}{3}}\pi R^{3}-{\frac {4}{3}}\pi r^{3}$ $V={\frac {4}{3}}\pi (R^{3}-r^{3})$ where r is the radius of the inner sphere and R is the radius of the outer sphere.

An approximation for the volume of a thin spherical shell is the surface area of the inner sphere multiplied by the thickness t of the shell:

$V\approx 4\pi r^{2}t,$ when t is very small compared to r ($t\ll r$ ).

## In popular culture

A Dyson sphere encloses a fictitious spherical shell around a star, as first described by author Olaf Stapledon.

## See also

This page was last updated at 2020-06-19 10:11, View original page

All information on this site, including but not limited to text, pictures, etc., are reproduced on Wikipedia (wikipedia.org), following the . Creative Commons Attribution-ShareAlike License

Top

If the math, chemistry, physics and other formulas on this page are not displayed correctly, please useFirefox or Safari