Ratios

Streaming video - 2004

The program introduces electric current and voltage and measures these in series and parallel circuits. An experiment to measure resistance is demonstrated and results are shown graphically. Resistance is introduced and calculated from the gradient of V–I graphs. Ohm’s Law is discussed and the V–I graph for a light bulb is plotted. Resistance is shown to depend on the type of metal, the length of a wire, the thickness of a wire and on the temperature, concluding with a demonstration of a superconductor. Animations of positive ions and free electrons explain the observed behaviour.