When I first heard this I thought it was fake news. But after a little bit of digging and reading I was more than sold.
If you look at the two images above, you can see the before and after of what happens when somebody puts a spoon full of oil into a choppy lake. You can see that in a ring around his boat is calm water in an expansive circle.
So why does this happen?
Basically, when tipped into water, the oil molecules don’t clunk together, but rather spread out to form a layer that is only one molecule thick. These oil molecules all flip over onto their negatively charged heads, and they stand atop the positively charged water particles (like molecular magnets). Because of this the oils spreads out across the lake to form a film over the water’s surface that is just a single molecule thick, meaning that you can calculate how big a single molecule of oil is by doing this.
So, for example, the spoon one used by one tester was about 0.39 inch (1 cm) high and the circle of oil it created on the water was roughly half an acre wide. When you divide this up to fit into the tablespoon used, it would fill the tablespoon roughly five million times, meaning that one molecule would be one five-millionth of a centimeter.
Why does the oil calm the water?
Usually the wind builds up waves by getting traction upon the surface of the water and moving it, but the layer of oil molecules on top of the water acts as a blocker for the wind’s traction, simply moving the layer of oil rather than creating waves.
It’s a pretty interesting trick, and it’s been used historically by all manners of people for different reasons.
Benjamin Franklin, pioneer of electricity, used this bit of know-how to prank people. He would tell people that he could calm a choppy lake with the touch of his cane, keeping a small vial of oil in the bottom of his cane that would come out onto the water’s surface when he tapped it, making him appear like a magician or some sort of choppy-water-calming God.
This trick has also been used in more useful ways than Benjamin Franklin’s practical joking too. Sailors, when bracing the roughest of seas, would dump all their cooking oil into the water to help stop the waves, gaining them and their vessel some reprieve.
Some ships would even carry several casks of oil for this very purpose.
Besides these previous historic applications, the science behind this is put into good use within our modern society. By putting a one-layer thick film of oil or a smaller molecule (like magnesium fluoride) onto glass it creates something known as ‘invisible glass’, which has barely any reflection or glare.
This is because the reflection from the glass and the reflection from the layer on top of the glass essentially cancel each out. This is the type of glass used for phone and tablet screens, laptops and glasses.
So there you have it people; a spoonful of oil can calm a choppy lake, and the applications of this dainty bit of bite-size knowledge range from practical joking to making smartphone screens!