In last week's column, I got into a spin about Frisbees, and astute readers noticed that the aerofoil shape generates a low pressure are above rather than a high pressure one. This is according to the Bernoulli Principle, named after the Swiss mathematician Daniel Bernoulli (1700-1782).
Bernoulli came from a family of mathematicians. His father, Johann was an early developer of calculus, and his nephew Jacob was a pioneer of probability theory. Daniel did not get on with his father, who appears to have resented his successful son. Johann banned Daniel from his house, and then plagiarized ideas from his son's book. To cover his tracks, he backdated his own work.
The Bernoulli Principle simply says that as a fluid (air) moves faster, its pressure lowers. That gives our Frisbee with some lift, although it's probably less important than the fact that it's tilted upwards slightly.
And of course, if you tilt your throw too steeply, the Frisbee loses forward momentum, and slides back towards you. Or more likely, it will veer to one side. If you're really good, it will boomerang back so you can catch it.
The Bernoulli Principle is related to the Venturi effect, named after the Italian physicist, Giovanni Venturi (1746-1822).
We used a venturi to drain water from the bottom of our dinghy. This is a simple device, not much more than an angled vent with a trapdoor lid. Intuitively, a hole like this would let water in, but as long as the boat is moving it's quite effective. The fast moving water under the boat sucks water out with a belchy gurgling sound.
Another extremely simple but useful venturi is used to indicate aircraft speed. A pitot tube is a slender tube with two holes in it. By monitoring pressure, airspeed is calculated.
When an Airbus A330 Flight 447 crashed on 31st May 2009, investigators deduced that the pitot tubes were blocked by ice as the jet flew through a thunderstorm on the way Paris from Rio de Janeiro.
More complicated perhaps, is the venturi inside a carburettor, where fuel is atomised as air passes over the venturi, before being drawn into the engine.