Glycerin. Glycerin is an ingredient that can be found in many beauty products because of its moisture locking properties. It is a form of sugar alcohol that is available naturally in vegetable oils and can also be the byproduct of soap making.
Definition of wheel and axle : a mechanical device consisting of a grooved wheel turned by a cord or chain with a rigidly attached axle (as for winding up a weight) together with the supporting standards
Nor are they always the best simple machine to use. It all depends on the work you want to do. A wheel and axle is a simple machine where two components rotate together to transfer force from one to the other. Think of your car or bike wheels or even a round doorknob, and you'll get the idea of this machine. When you put a rope or cable around a wheel and axle, you get a pulley.