MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY
Untreated and amalgamated aluminium foil. Untreated aluminium foil (left) is unreactive in air because it forms a protective oxide layer. Amalgamated aluminium (right) is formed of amalgamated fine particles of aluminium, and, like aluminium powder, is much more reactive because of its greater exposed surface area. Amalgamated aluminium is pyrophoric, and can spontaneously ignite in moist air, which is what has happened here.
Model release not required. Property release not required.