By David Robinson, updated March 24 2022
Harnessing the natural acidity of a lime to generate electricity is a classic classroom demonstration—and a surprisingly practical experiment for the home. A single citrus fruit can power low‑energy devices such as an LCD clock or LED light for up to a week.
Gently squeeze the lime to rupture the juice‑filled cells while keeping the rind intact. The more surface area you expose, the stronger the chemical reaction.
Strip about an inch of insulation from one end of the copper wire and straighten a paperclip. Clean any rust or residue so the metals are smooth and shiny.
Insert the copper wire into one side of the fruit and the paperclip into the opposite side. Ensure the metals do not touch. When you connect the two electrodes with a low‑voltage wire, a small voltage will flow.
Measure the voltage with a multimeter between the copper wire and paperclip. Avoid leaning over the fruit to prevent splashes.
After use, discard the lime. The acidic juice can corrode the metal probes and leave harmful residues if the fruit is consumed.
