On this day in 1700, the great mathematician and physicist Daniel Bernoulli was born. He is from the amazing Bernoulli family — a group of about a dozen famous people — mostly mathematicians. But trust me, you’ve only ever heard of Daniel. He is what Bernoulli’s principle is named after. It represents about the most basic kind of fluid dynamics. And it is based upon it that I’ve long maintained that instead of electrodynamics being one of the three linchpins of physics, it could be fluid dynamics. They are effectively the same thing and they teach the same concept: flow.

Imagine a pipe that has a cross sectional area of 2 square meters that connects to a pipe of cross sectional area 1 square meter. If water is flowing through that, the total quantity of the water going through each section must be the same. Thus, the water must be flowing at twice the speed through the small pipe as it is through big pipe. That’s all just straight intuition. But because of energy conservation, this means that the pressure in the small pipe must be reduced from what it is in the large pipe.

Fundamentally, Bernoulli was a mathematician. But he was a practical guy, even if he wasn’t out measuring things. But he did important work in statistics and vibration. But you know: this was in the early days when mathematicians were still doing work that I understand. I mean, much of Bernoulli’s work was straight differential equations. I have to admit, though, that it is really nice to actually understand this stuff. Even 50 years later, mathematics becomes far more abstract. I would be very pleased if I could understand math up through 1850 by the time I die. It is highly doubtful.

Happy birthday Daniel Bernoulli!