This sub-strand deals with simple machine technology. The structure of an object determines its stability. An object is in stable equilibrium (balanced) when its centre of gravity is above its base. A small machine allows a small force (effort) to overcome a large force (load). This is the principle of the machine. A machine that increases force gives a mechanical advantage. A machine that increases movement gives an advantage called velocity ratio. Complex machines are made up of many simple machines joined together. Machines transfer energy and do work.
8.1.2.1 explain that the transfer of energy does the work in simple machines. Use a lever (e.g. crowbar lifting a rock) 8.1.2.2 list three classes of lever systems and identify the (effort, load, & pivot) positions in each system
8.1.3.1 demonstrate that the turning forces in a lever is the forces applied times distance from the pivot 8.1.3.2 use a See-saw arrangement to demonstrate the turning force effects in levers
8.1.4.1 calculate the mechanical advantage by dividing the load by the effort for different simple machines 8.1.4.2 calculate the velocity of a pulley system by dividing the distance moved by the load by distance moved by the lever
8.1.5.1 perform the following tasks to demonstrate the use of simple machine; i. remove the nail from a timber using a hammer (lever) ii. carry stones in a wheel- barrow (lever) iii. dig potato using sticks iv. open a soft drink bottle 8.1.5.2 identify simple machines Which; i. multiply (increase) force (eg, tap knob, door knob ii. multiply (increase) speed (eg, bicycle gears, fan belt in vehicle)