99 ISSUE/PROBLEM (society issue, issue that is seen relevant from pupils’ perspective, issue linked to some nature phenomenon or phenomenon from pupils’ everyday life) The painting Kyrö Rapids shows a building, a sawmill, where the power of moving water was transferred to equipment for sawing logs into boards. Leverage was used in the transmission, among other things. Leverage is effective because when the fulcrum of the lever arm is near one end thereof, a small force can produce a large amount of movement. Lifting the load is lighter the closer the load is to the fulcrum and the longer the lever arm is. The long arm of the lever thus facilitates the work, for example, when crocheting a heavy object to another location. A support point placed close to the object to be moved facilitates the work. Try this in practice. INVESTIGATIONAL STAGE DESCRIPTION OF THE ACTIVITY Try moving a heavy object first with a short, then a long lever. Test the effect of a support point placed near or far from an object (such as a stone or a piece of plank under a lever). If you are levering a very heavy object, take care of your safety. The lever arm should be made of durable material, as the force on the lever arm can be so great that the lever arm pops out uncontrollably or breaks violently. TASKS Test the efficiency of the lever arm in practice with tools found at home. GOAL OF TASKS Understand and test the basic concept of forces and levers.