Thames-Kosmos-Ignition-Series-Physics-Simple-Machines-Thames-Kosmos-700001-P-Establish-a-foundation-in-physics-by-building-models-of-all-six-simple-machines-levers-pulleys-inclined-planes-screws-wedges-&-wheels-&-axles-P-P-Assemble-&-use-a-spring-scale-to-measure-how-the-machines-change-the-direction-&-magnitude-of-forces-making-work-easier-to-do-P-Thames-Kosmos-700001-Ignition-Series-Physics-Simple-Machines