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Hello, Aristotle thought there were four elements, Earth, Air, Fire and Water.

He was wrong.

There are 110 so far, 16 of which are produced artificially,

and none of which figure in Aristotle's original fall, but they're all still elements

define the substances which cannot be broken down, the building blocks of all life.

Today we have the key to the understanding of these elements the periodic table of the

elements which is a pattern embedded in nature and was as it were miraculously

discovered in a dream. With me to discuss chemistry's continuing mission to

understand the behavior and

relationship of these irreducible substances. He's Dr Mary Archer visiting

professor of chemistry at Imperial College London. John Meryl, emeritus professor

of chemistry at Sussex University, and Paul Strathon, author of

Mendeliev's dream the quest for the element. Paul Strathon, why did Aristotle choose

earth, fire and water and why did you think that these were the four elements?

He arrived at this. Well he wasn't the first person to think of these four as a combination.

It was Empedocles who did that. He took this the idea on from Empedocles who had the four, the notion of the four.

At one stage a very lovely poetic image, he describes how a stone falls into a pool.

He thought that the four elements, the heaviest ones at the bottom, earth, then you had water, then you had air, and then you had fire.

And he describes his evidence as being when a stone drops into a pool, it drops to the bottom

of the water, and the bubbles adhering to it are then drawn towards

...