Physics moment

So this is a bit of a nerd moment for me but it is truly fascinating. So I'm learning about "Resonance frequency" in physics. without all the equations, it is basically the one magic frequency that picks up the one special signal we are looking for, whether it's our phone or radio (tuning), it's that one magic frequency that amplifies the signal we are looking for.

For example, like a pendulum. when we were kids we learned to swing on the swing set. We had to find that perfect rhythm of pumping our legs to go the highest.

Another example is of course the sounds waves of a soprano breaking a wine glass.

The video below is what happened to this bridge in Washington in 1940 that went across the Tacoma Narrows strait of Puget Sound. What happened was the wind created a periodic frequency that matched the natural structural frequency of the bridge, and it collapsed!

"Much of the catastrophic collapse was caught on motion picture film thanks to Barney Elliott, the owner of a local camera shop. Examination of the film, the bridge’s remains, and tests with scale models determined that resonance was responsible for Gertie’s demise. Due to the design decision to replace the lattice supports with “I” beams, the wind was unable to pass under the structure as readily as it it passed over it, causing a difference in pressure much like an airplane wing. Once there was sufficient sway to tilt the deck slightly, aerodynamics caused the roadbed to twist to the point that it sprang back, causing a repeating cycle of back-and-forth twisting. During this process, the steadily blowing wind added more and more energy to the vibrations."

"Though no human life was lost when Gertie fell, Tubby the cocker spaniel did not survive." (Sad!)

He was the little puppy in the car that you can see in the film. Apparently the driver got out of his car to run for his life, and left his dog! Sad!

There's your physics lesson for the day!