Cullam Hart-Woodcock, of room 4 at Redcliffs School, asks :-
Is a screwdriver a machine?
Reg Dunlop, a mechanical engineer at the University of Canterbury, responded.
A machine involves multiple parts and usually changes energy from one form to another. The machine may be automatic such as a plastic moulding machine, or may need a human to operate it e.g. a hand held power drill. A tool allows a human to "amplify the effort". A screw driver does this by allowing a human hand to increase the amount of torque or twisting action applied to a screw. It also protects the soft hand from being damaged by the forces on the screw.
Another related item is the "machine tool" which allows a machine to do the same tasks as a human caried out with hand tools. Usually the machine tool is able to produce parts more accurately and faster than a human but often needs to be supervised by a human.