Resonance

Introduction: I'm doing a demonstration on resonance and frequency using silica sand. I'm showing

the creation of standing wave patterns by find the natural frequencies of the sand when it vibrates.

Materials:

-Mechanical vibrator

-Sine wave generator

-Silica sand

-Salt shaker

-Black square plate

-Big container

Procedures: First fill the salt shaker with silica sand. Then, put the black square plate onto the mechanical

vibrator. Turn on the sine wave generator and turn the frequency to 70 and turn up the amplitude a little. A

standing wave pattern in the form of an circle will form. Then remove that sand and put more sand. Turn the

frequency to 84, an x-shape will form. Then remove that sand and put more sand. Turn the frequency to 130;

a diamond shape will form. Then remove the sand and put more sand. Turn the frequency to 55, two parallel

lines will form. Four natural frequencies of silica sand were found.

Scientific Principle: All objects have a frequency or set of frequencies with which they naturally resonate (vibrate)

when struck, plucked, or somehow disturbed. Each of these natural frequencies at which an object resonates is

associated with a standing wave pattern. A standing wave pattern is a vibrational pattern that is created within a

medium with the vibrational frequency of an object causes reflected waves from one end of the medium to interfere

with incident waves from the source. These patterns are created by harmonic frequencies which are the specific

frequencies required to make that vibration.

Safety Regulation: Avoid inhalation, eye contact and eating silica sand. Silica sand contains the chemical crystalline

silica which is known to cause cancer or birth defects or other reproductive harm.