Thursday, 3 March 2011

How a housewife changed the world!!

This morning I was talking to a colleague of mine about hobby scientists. People at home that buy a microscope, people that find some interesting physical phenomenon and post on youtube using their LCD displayed smartphone, or the many astronomers looking to the sky to find solar bursts. Science can be found everywhere around us like in the night sky, out in our backyard and even in our kitchen sink. What better place to discover science than your kitchen sink?

A German woman and independent scientist, Agnes Pockels, did just that in 1890. Legend has it that doing the dishes in her own kitchen Agnes discovered the influence of impurities on the surface tension of fluids. So she set out to measure these surfactant impurities (different oil from cooking) and started experimenting. To measure the tension she developed the Pockels trough, precursor to the Langmuir scale, and published the first stearine acid. She wrote to Lord Rayleigh a scientist at Cambridge (who discovered Argon which later won him the Nobel Prize) shortly after he published initial suggestions that oil might form a monolayer on water.

In this letter she described an apparatus she had designed to measure the surface tension of monolayers of hydrophobic and amphiphillic substances. Agnes made a simple trough from a tin pan with tin inserts to determine the size of a surface. She had a balance on one side with a 6 mm disk to the measure the force required (e.g. the surface tension) to pull the disk from the surface. With various oils she hand around the house she described the behavior of surface tension. She added to this by calculating the amounts of material required to form a monolayer and commented on the purity and cleanliness required to accurately perform measurements of surface tension. She also reported the thickness of the film of the of various amphiphillic substances on the surface of water. Quite extraordinary for a housewife. The paper was published in Nature!!

Now monolayers and Langmuir-Blodgett troughs (they later modified Agnes Pockels' home built trough) are used to uncover many fascinating discoveries. For example they are used to fabricate nanoscale electronics using materials like graphene, understand how drugs permeate into the blood brain barrier, or fabricate LCD (liquid crystalline display) for your smartphone. So the next time you pick up your smartphone think about Agnes Pockels and try not to drop it in the sink.