Why do some buildings fall in earthquakes? Animated video addresses the key points of frequency, period, and resonance. All buildings have a natural, period, or resonance, which is the number of seconds it takes for the building to...

A USGS seismologist demonstrates how to use spaghetti noodles and raisins to model building resonance during earthquake ground shaking. [1:21]

Learn how sound is made with standing waves in open tubes. [14:19]

This activity transforms the vibrating air molecules from your voice into Lissajous patterns, allowing you to visualize harmonic motions and resonant vibration modes. [1:53]

The video lesson from Khan Academy provides instructional content for the AP Chemistry course. This video lesson models how to draw resonance structures and resonance hybrid using the example of nitrate anion.