Strobe Wave

Israel Estrada & Joseph Paiano

Inside the box is a strobe light which illuminates the three strings. When the strings are plucked, they vibrate under the strobe light, and a form of their vibration becomes visible. Depending on where a string is plucked, you may end up seeing different vibrations. Shown below are diagrams of the fundamental vibration as well as some other vibrations known as the harmonics. The points where the vibration amplitude is zero are called nodes and the points where it is at its highest are called anti-nodes.

Fundamental Vibration	First Harmonic	Second Harmonic
	Third Harmonic	Fourth Harmonic

Strobe lights can make moving objects appear to slow down, speed up, or even stop. The diagram below shows the motion of an object (from left to right) under a strobe light. If only the bolded images are lit under the strobe light, then only certain positions, or frames, of the object can be seen. These frames make up part of the object’s actual movement, just not the entire thing.

The next diagram shows the clockwise movement of a knob. Only the bolded images are lit under the strobe light. So, only one of the object’s positions is seen (the 12:00 position), thus making the object appear to be still. This only works if the flash rate and the object’s speed are equal.