Vertical flask type demonstration model, on metal base. In a two stroke engine, to perform full cycle of operations (changing the contents of cylinder and effecting combustion) two strokes of piston are required. This type of engine is mostly used in petrol driven scooters.It is an internal combustion engine. The thermal energy which is released when fuel is burned is converted into mechanical energy. Petrol is mixed with air in a device called carburettor to form a combustible mixture which is compressed in a cylinder and finally ignited by an electric spark produced between the electrodes of a sparking plug. The gases which are formed in the cylinder by the combustion of air petrol mixture, expand, and thrust the piston downward. Acting through the connecting rod, the piston imparts a rotary motion the crankshaft. The energy to remove spent gases from the cylinder is provided by the flywheel thus paving the way for injection of fresh air petrol mixture, so that a new cycle can begin