Four Elements

Aristotle, known as the father of biology, believed everything in the Universe to be made up of the 4 Elements-Earth, Air, Water and Fire and that idea held for nearly 2000 years. But, it wasn’t so simple, water was considered anything liquid, so yes water but also milk, wine, blood, acids. While fire could be anything to do with light, so lightning was considered fire, but the smoke from fire would be considered air as was the steam from boiling water.