Who Split the Atom?

Who Split the Atom? — page 3 — Nothing exists except atoms and empty space everything else is just opinion Democritus declares his view of reality However that long ago there was no way of really looking at atoms and Leucippus and Democritus had no good evidence for their idea They simply thought it seemed like a sensible explanation It happened to be along the right lines according to what we know today but this was only proved in the last 200 years Ancient ideas The ancient atomists The idea that everything is made up of tiny units has been around since ancient times The name atom comes from an ancient Greek word atomos which means uncuttable or indivisible The word was ﬁrst used by two ancient Greeks Leucippus and his follower Democritus who lived around 2,400 years ago They used it to describe little invisible units that they believed everything was made of They also correctly thought that there were different kinds of atoms of varying sizes which made up every kind of material People who agreed with this theory were known as the atomists Ancient Indian Buddhist thinkers around a thousand years later had similar ideas known as Buddhist atomism Democritus is such an important ﬁgure in Greek history that he was featured on the 100 drachma bank note The drachma currency was replaced by Euros in Greece in 2002 8

Who Split the Atom? — page 4 — According to ancient Greek religion the sun was a god Helios riding his chariot across the sky But Democritus realized the sun was a phenomenon like all the other stars in the sky THAT’S A FACT Atoms weren’t the only thing that Democritus was uncannily right about He studied many subjects and came up with all sorts of ideas He claimed that the earth was round that the Milky Way was made up of stars and that early people didn’t have language but developed it gradually Scientists today have found evidence that proves all these things to be true Greek philosophers Many ancient Greek philosophers spent a lot of time wondering about how the world worked While some suggested everything was made up of atoms others thought everything was essentially made of water or from different types of air While they didn’t always guess correctly this way of asking questions and coming up with ideas was very important It paved the way for modern scientiﬁc thought and methods Breakthrough More than 2,000 years ago the ancient Greek atomists Leucippus and Democritus came up with the ﬁrst theory of atoms and how they make up all substances Their ideas were not widely adopted but they would be revived much later 9

Who Split the Atom? — page 5 — Understanding matter The four elements Despite the atomists theories most ancient philosophers thought that instead of many types of atoms there were just four basic substances or elements earth ﬁre air and water The idea of these four elements carried on for many centuries into medieval and Renaissance times However in the 1600s a new age of detailed scientiﬁc study was born and people began to question the four elements A new approach Scientists did careful experiments mixing combining and breaking down different types of substances to see what they were really made of It became clear that there had to be more than just four ingredients making up the universe Brilliant Boyle One of the most important scientists of the time was Irish experimenter Robert Boyle He argued that matter was made of atoms after all and that there were many different types of basic atoms and elements not just four He wrote a book called The Sceptical Chymist published in 1661 explaining that atoms moved around and joined together in groups to make different substances Robert Boyle Date of birth January 25 1627 Place of birth Lismore Ireland Greatest achievement Boyle revolutionized the science of matter turning it from superstitious alchemy into modern evidence based chemistry Interesting fact Boyle was also interested in anatomy and finding out how the bodies of animals and humans worked but he couldn’t bear to dissect bodies as it made him feel ill Date of death December 31 1691 10

Who Split the Atom? — page 6 — Alchemy Boyle’s work grew out of alchemy an ancient practice of trying to treat or change everyday substances such as lead and stone to create more valuable substances such as gold It didn’t work but it did involve a lot of experimentation and resulted in some useful discoveries Boyle said that scientists should do proper careful experiments to ﬁnd clear evidence of what matter was made of and how it worked This was really the beginning of the modern science of chemistry the study of substances and how they behave join break apart and change Boyle studied many things including how gases behave under pressure and how freezing and burning worked Thanks to Boyle old myths were replaced with proper experiments and evidence and the idea of four elements was swept away The search began for the real elements the many different types of atoms This 19th-century painting by William Fettes Douglas shows an alchemist at work You can see his chemical-mixing equipment and a potion he is concocting Breakthrough Robert Boyle’s book The Sceptical Chymist 1661 and his experiments marked a new direction in the study of the science of matter 11

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