ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Electrolysis. Pencils being used as the electrodes in the electrolysis of potassium iodide solution (in the flask). The wood in the pencils does not conduct electricity, but the graphite in the core of the pencils does. Graphite's structure allows it to conduct electricity, unlike other forms of carbon. The crocodile clips (upper right) connect the graphite to an electrical power pack (left). Potassium iodide is an ionic solution, meaning the flow of its ions completes the electrical circuit. At the electrodes, iodide ions form iodine (yellow stain) and potassium ions form potassium, which reacts with the water to produce hydrogen bubbles.
Model release not required. Property release not required.