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
The wheel and axle are primarily used for moving items and for transportation. It vastly reduces the friction between objects by converting it to a rotational motion. Common non-vehicular axles are seen in roller conveyors (with or without covering belts). A door knob is the reverse version of a wheel and axle. It translates a small force on the turning wheel to operate the axle (cylinder), which turns the door spindle (bolt).