Matter and Elements

The ancient Greeks thought that all matter in the universe was made of four elements, earth, air, fire and water in different quantities. Thus wood may have comprised earth with water and fire (apparent when the wood was burned).

They also believed that there was a minimum quantity of an element that could exist and still retain the properties of the element. Democritus (460-370BC) called this an 'atom' from the Greek for "uncuttable".

This concept of an atom then remained virtually dormant until John Dalton revived it in 1803. Today we know that there are over 100 elements of which 90 or so occur naturally, the rest being artificially created.

We also know that the Greek concept of the atom was correct though the atom is now known to comprise smaller particles called electrons, protons and neutrons.