Lever & Fulcrum is a simple demonstration where a metre rule balances at its mid point on a vertical pillar mounted on a base to rest on the table. It shows that when the weight x the distance (the moment) on one side of a pivot point equals the weight x distance on the other side, the system balances because the 2x moments are equal. The kit includes 2x 50g special slotted weight carriers that hook over the edge of a standard metre rule and can be slid to any point. Because schools have many suitable weights, the slotted weights themselves are not supplied. The 1m wooden rule has a knife-edge fitted at the mid point and the support has a vee bearing to take the knife-edge.