Hi there. If energy can neither be created or destroyed then how do lightbulbs work? Is it because the electricity in the circuit changes from one form of energy to another? Or will the theory be debunked at sometime? Thanks!
The energy conversion is: 1) electrical energy is dissipated in the filament (i²R) -> into thermal energy, which heats the filament to incandescence, so that 2) some of the thermal energy -> light energy (energy of the photons that make up the light), and then when the light is absorbed by the objects it falls on, 3) light energy -> thermal energy, in those objects.
Lightbulbs take energy from the electric current flowing through them and give it to the light that they emit. The energy is merely "converted" from one form to another. Different kinds of lightbulbs convert the electrical energy into light energy in different ways.