Atoms of Fire: Atoms and organic compounds

WOMAN: The Greeks had many ideas about the chemistry of things. But the one who came closest to the truth was Democritus. He said that if you divided matter down and down and down, or cut it up finer and finer, eventually, you would get to something very tiny that couldn't be cut down any further. And this, he said, was the smallest possible thing. And he called it an atom. which means Greek for 'cannot be divided'. Democritus said everything was made of these and you could make new substances by rearranging them. And this is very close to the truth as we know it today. And that's an amazing statement to have come out with 2,500 years ago.

NARRATOR: Democritus saw atoms in all things. He believed that there was a human soul made of atoms of fire, which gave the body movement. This idea that the chemistry of life was somehow a special case would be revived 2,000 years later. Even as late as 200 years ago, chemists separated matter into two major groups based on the test of fire. Wood or hair or flesh would burn up into smoke. Water or stone or metal did not burn. It seemed as if there was a great difference between the material of life and that which came directly from earth or sea or air. It was known as the 'vitalist divide'. The great chemist Jons Berzelius named the materials of life organic and the others inorganic. Only living tissue, he said, could make an organic compound.

WOMAN: Berzelius comes along at the beginning of the 19th century, when the push to understand chemistry really gets under way. It's Berzelius who proposes the system of chemical symbols that we use today. For example, H2O for water. He takes the first letter of the name — H for hydrogen and O for oxygen — and puts them together in the proportions that they combine. Two parts hydrogen to one part oxygen. He knows he can't break hydrogen or oxygen down any further. He knows that they're elements so he accepts that they are different types of atoms. There's a lot of argument about it at this time but, basically, this is the beginning of modern chemistry.