Kinetic Energy to Electrical Energy to Light Energy

JSSS

Energy Conversions OP21, OP60

Kinetic energy to electrical energy to light energy

In this apparatus the kinetic energy of moving air is converted to electrical energy, which is in turn converted to light energy. The kinetic energy may have been converted from chemical energy (food) stored in our bodies and released through respiration, or from electrical to kinetic in a hairdryer.

Using an electric motor

The apparatus consists of a set of blades attached to a generator which can be connected to a 6V bulb or to a light-emitting diode. Blowing on the blades causes them to rotate. When the blades rotate they cause the magnet in the motor to rotate in the coil. This produces an emf (voltage). If it is connected across the LED, there is sufficient electrical energy to light the LED. When connected across the bulb it just produces a faint glow.

Background on electromotive force (emf)

Electrical energy can be generated by moving a magnet relative to a coil of wire that is in a closed loop. It does not matter whether it is the coil or the magnet that moves. This is the basis of all electrical generators. This can be demonstrated by moving a coil of wire into and out of a coil of wire that is attached to a sensitive milli-ammeter.