Why do buildings fall in earthquakes? - Vicki V. May

Earthquakes have always been a terrifying phenomenon, and they’ve become more deadly as our cities have grown — with collapsing buildings posing one of the largest risks. But why do buildings collapse in an earthquake? And how can it be prevented? Vicki V. May explains the physics of why it is not the sturdiest buildings, but the smartest, that will remain standing.

 Lesson by Vicki V. May, animation by Pew36 Animation Studios.

Why Blowing in Bottles Makes Sound and Helmholtz Resonance

An explanation of why blowing in a bottle makes a sound, basically explaining how Helmholtz resonance works and how to bottles are Helmholtz resonators. The same explanation works for what role the speaker plays in moving objects/bottles using sound, the acoustic propulsion in one of my other videos below. This also explains a bit about resonant frequency and compares the sound wave compression and decompression to an oscillating spring, a simple harmonic oscillator.

 

Hewitt-Drew-it! PHYSICS 85. Resonance of Sound

Explores the nature of natural frequency and resonance, with applications.

 

Standing Waves and Resonance

Standing Waves can resonate in a pipe. The resonance occurs in an open-closed pipe when an odd integer number of quarter wavelengths fit exactly in the length of the cavity of the pipe. This animation illustrates what happens when a plunger is used to "scan" the effective length of a pipe driven by a tuning fork. Three different cases are shown for a set of increasing frequencies.
 

MIT 8.02 Electricity and Magnetism Lecture 27

MIT 8.02 Electricity and Magnetism, Spring 2002

Professor Walter Lewin

Resonance; Destructive Resonance; Electromagnetic Waves; Speed of Light; Radio - TV; Distance Determinations using Radar and Lasers

Other lectures from the same course


 

Tuning Forks: Resonance & Beat Frequency

Two identical tuning forks and sounding boxes are placed next to one another. Striking one tuning fork will cause the other to resonate at the same frequency. When a weight is attached to one tuning fork, they are no longer identical. Thus, one will not cause the other to resonate. When two different tuning forks are struck at the same time, the interference of their pitches produces beats.

See other MIT physics demos

Resonance using Audacity

How to show resonance with a tuning for and the software Audacity.


 

Theremin - Sixty Symbols

If ever a musical instrument was designed for physicists, it was this one.

Other Sixty Symbols videos

The Tacoma Narrows Fallacy

The collapse of the Tacoma Narrows bridge wasn't resonance.

Other Minute Physics videos

MIT 8.01 Classical Mechanics Lecture 31

MIT Physics Course

Professor Walter Lewin

8.01 Physics  I: Classical Mechanics, Fall 1999

Forced Oscillations - Normal Modes - Resonance - Natural Frequencies - Musical Instruments

See other videos in this series.

Chladni's Plate - Sixty Symbols

We showed Chladni's plates before, but this video has explanations too...

Other Sixty Symbols videos

Physics of the trumpet 1

Resonance, standing waves in a string with both ends fixed, penny whistle.

With Nick Drozdoff.

Other videos in this series

Synchronization of Metronomes

Five metronomes are set to 176 bpm and placed on a Foam Core board. When empty cans are placed underneath, the board is free to move from side to side and the metronomes are able to influence each other into synchronization. When the cans are removed the metronomes are no longer physically coupled and some of them begin to fall out of step.

Other Harvard demonstrations

Introductory NMR & MRI: Video 01: Precession and Resonance

Paul Callaghan gives an introduction to NMR and MRI. Paul uses a mechanical wheel to illustrate the key concepts of precession, relaxation, and resonance. First in a 10 episode series produced by Magritek Ltd.

Source:  Magritek

Thanks to Stan Sykora (owner of  Stan's Physics Links) for this great suggestion.

View other videos of this series.

MIT Physics Demo -- Resonant RLC Circuit

A variable capacitor (C), large inductor or solenoid (L), and 200W light bulb (R) are connected in series to 120 VAC. The inductance of the inductor can be varied by inserting an iron core, and the capacitance can be varied by a row of switches. By varying the inductance and capacitance, we can achieve the resonance of the circuit, where maximum current flows through the resistor (light bulb)

Source:  MIT TechTV

See other MIT physics demos

Breaking glass with sound

High speed video showing glass being broken by sound.

Standing waves in a large tank

Standing waves in a large tank at the United States Naval Academy.

Chladni Plate (sand vibration patterns)