Number, Measurement and Space, module establishes equivalence of sets by a one-to-one exchange of objects. Eg Upsetting equivalance (destroying conservation of numbers) by adding one object to a set, or taking one away, helps introduce vocabulary for comparing quantity
Free Fall Apparatus Economy, for determination of the gravitational constant ft gft, This kit has a wooden base, 1.1m rod and a movable electro magnet, can be moved anywhere on the rod, when the ball is released the timer is triggered and stopped one the ball his landed on the base