Atom 1. The Clash of Titans (5 of 30)

Atom

The one that made all the difference was a short paper on how tiny grains of pollen danced in water.
Almost 80 years earlier, in 1827, a Scottish botanist called Robert Brown sprinkled pollen grains in some water and examined it through a microscope.
What he found was really strange.
Instead of the pollen grains floating gently in the water, they danced around furiously, almost as though they were alive.
Now, while this so-called "Brownian motion" was strange, scientists soon forgot about it.
They found it mundane, even boring.

Who cared if the pollen jiggled about in the water?
And what had the jiggling to do with atoms anyway?
For nearly 80 years, Brown's discovery remained a little-known scientific anomaly.
Then Einstein changed everything.
In one staggering insight, Einstein saw that Brownian motion was all about atoms.
In fact, he realised that the jiggling of pollen grains in water could settle the raging debate about the reality of atoms for ever.
His argument was simple.
The pollen will only jiggle if they were being jostled by something else.
So Einstein said that the water must be made of tiny atom-like particles which themselves are jiggling and continually buffeting the pollen.
If there were no atoms, then the pollen would stay still.
So Boltzmann and his contemporaries had been rowing furiously about this question for nothing.