(B) Use power drill with Styrofoam cut-outs mounted on
dowels. When the styrofoam rotates it traces out
the solid of revolution. Click here for a picture
(C) Do some edible calculus (by Nancy Dirnberger): (USE after SHELL METHOD)
If you core an apple you have a great solid of
revolution with a hole through the solid! An apple
is usually sliced in one of two ways. If you slice
it so that the plane of the slice contains what
would be the axis of revolution, your apple slice
(actually you have two) is a disc of revolution. You
can almost slice it thin enough to have width dx! If
you slice the apple into rings, the resulting slices
are washers that will give you the same volume when
added. With a large, thick slice of a Bermuda onion
you can pull up onion rings as successive
cylindrical shells. Students often have a problem
visualizing these cylindrical shells.