Disks and Washers for solids of revolution

These 3D models illustrate the "disk" and "washer" methods of computing volumes of revolution—typical topics in the calculus sequence.

One model shows the case of the region bounded by x = f(y) = sqrt(3/4 – y) + 1, x = g(y) = 1/4 + y, y = 0, and y = 3/4 revolved about the y-axis. You can download the solid or the approximation with 10 washers.

The other model shows the case of the region bounded by x = f(y) = 1 – y², y = 0, and y = 1 revolved about the y-axis. You can download the solid or the approximation with 10 disks.

I have also included the OpenSCAD file, which is set up so you can modify the functions or parameters to produce your own model.