On this day in physics: 08 February 1700- Happy Birthday to Daniel Bernoulli who was a physicist and made large contributions to the field of fluid dynamics. He is also the Bernoulli of the famous "Bernoulli Principle" or "Bernoulli Equation" (more below).
Word of the Day: Bernoulli Principle- The Bernoulli Principle is something that describes fluids in motion, or flowing. Imagine fluid flowing through a pipe of a certain radius, it will have a certain pressure, and velocity. If this pipe was to narrow, the surface area and radius decrease and the velocity of the fluid will increase, but what about the pressure? The intuitive response is that the pressure increases. However, what Bernoulli tells us is that the pressure at this bottleneck is actually LOWER. What the heck? How can it be? Well, Bernoulli's principle is sort of just another expression of conservation of energy, or Newton's Second Law. Because the velocity increases, and there is no increased energy being injected into the system, as the Grateful Dead say in the song New Speedway Boogie "something's gotta give", and that thing is the pressure.
A phenomenal example of Bernoulli's Principle in action is a perfume atomizer. How does it work? Well, you have this bulb full of air travelling at no speed whatsoever, and then at the top of the perfume bottle there is a small tube or straw which runs down into the perfume. When you squeeze the bulb, what happens? The air (air is a fluid by the way) moves very quickly out of the nozzle, but what happens is that the pressure in this area goes way down. The liquid and bottle, now at a higher pressure, react by pushing the fluid up the tube and into the nozzle. The air also moving quickly pulls the liquid off in little tiny beads, which then make a beautiful perfume vapor in the air for ladies everywhere to enjoy.
Quote of the Day: "Nature always tends to act in the simplest way." - Daniel Bernoulli [Source]
Keywords: Bernoulli, Velocity, Energy, Pressure
