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
Ex: Screw Driver (Handle = wheel & Shaft = axel) A wheel & axel is a simple machine made of 2 circular or cylindrical objects that are fastened together & rotate about a common axel.