ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Conductivity test. Carbon (grey, below centre) is being used to complete a circuit. Unusually for a non-metallic element, carbon is electrically conductive, so current flows through it. Hence the light bulb is on and there is a reading on the ammeter.
Model release not required. Property release not required.