Resistance of a wire – material, length and cross-sectional area

Integrated ScienceElectricity & MagnetismAges 14–15

Choose the wire material (silver, copper, aluminium, tungsten, iron, nickeline, nichrome or a custom resistivity) and drag the length and cross-sectional area sliders; the resistance R = ρ·L/S appears at once, and each symbol in the formula grows or shrinks with its value. The wire on the canvas gets longer or shorter, thicker or thinner and changes colour with the material, while the density of dots inside the wire rises with resistivity. Record data in the table and view the graph of R against length to find that R is directly proportional to L and inversely proportional to S. Adapted from the "Resistance in a Wire" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Resistance, Ohm's law