30.3 MB (2.5 MB compressed)
3979 x 2663 pixels
33.8 x 22.6 cm ⏐ 13.3 x 8.9 in (300dpi)
TREVOR CLIFFORD PHOTOGRAPHY / SCIENCE PHOTO LIBRARY TREVOR CLIFFORD PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Editorial use only.
Lemon clock. Two lemons being used to provide electrical current sufficient to power an digital clock. The lemons are being used as electrolytic cells, the electrolyte being citric acid. Four electrodes - two copper and two zinc - are placed in the lemons and connected together. Zinc atoms on the electrode are oxidised, losing two electrons per atom and dissolving into solution. The electrons pass through the wires to the copper electrode where they combine with hydrogen ions to liberate hydrogen gas. The movement of electrons between electrodes forms the current.
Model release not required. Property release not required.