Meet Smart Scientist Robert Brown who has been credited with the discovery of Brownian motion.
Robert Brown (21 December 1773 – 10 June 1858) was a Scottish botanist whose place in history was earned by the observations of how starch grains from pollen move across the surface of water, a movement that we now call Brownian motion.
Robert Brown and Brownian motion
Robert Brown in 1855 (http://en.wikipedia.org)
Robert Brown was born in Scotland in 1773. He started his career as a surgeon but decided that he preferred to study plants instead, so became a botanist (a botanist is a scientist who specalises in plants).
Between 1801 and 1805 he spent time in Australia which had recently been discovered by Europeans. This must have been an exciting but dangerous expedition for Brown, with the discovery of lots of plant species never seen by the rest of the world. On his return to Britain, Brown was put in charge of the botanical department in the British Museum.
One day in 1828 he was using a microscope to study tiny particles of starch that were inside pollen grains. He placed some on the surface of some water and noticed that they moved around in a jittery motion. Rather than just accept this, he wondered why this happened – were the starch particles alive?
To test this hypothesis he studied finely ground up charcoal and metals, which were non-living, and observed that they also moved. He wrote down his findings in a scientific journal so that other scientists could read about his discovery, which he called Brownian motion.He could not give a scientific explanation for what he saw but thought that perhaps others could.
In fact, it wasn’t until the early 1900s that his work was rediscovered by a scientist called Albert Einstein (you may have heard of him!). Einstein published a paper that explained in detail how the motion Brown observed was a result of the starch particles being hit by water particles. So, even though Robert Brown couldn’t explain what he saw, his work helped Einstein to prove that atoms existed!
Did you know?
Brown’s Banksia – an Australian plant named after Robert Brown (http://en.wikipedia.org/)
Robert Brown did important work on cells. He gave the nucleus its name. He was quite fond of having things named after him. In Australia there are many plants, a river and even mountains called Brown.
Brown wasn’t the first person to notice this phenomenon. In 1785, a scientist called Jan Ingenhousz described the movement of coal dust on the surface of alcohol.
Further Work:
Your students can find out more about Brown and Einstein’s work by
watching the Free video: Random force and Brownian motion
or reading the Smart facts: Brownian motion.