Physics Girl: Resonance (10min)

What is an oscillating system?

• A system for catching flightless birds.

• Like supply and demand in economics with price variations.

• A system that goes back and forth.

Resonant (or Natural) frequency is the frequency that it will continue at if you 

• push it over and over

• just let it go.  It naturally wants to have that frequency.

What is the best way of finding the resonant frequency of a wine glass?

• Break the glass, and record the sound of the breaking glass.

• Find the area, and divide it by the mass of the glass.

• Flick the glass with your finger.

A musical note can be described by its ______.

• color (higher notes are blue)

• mass (higher notes are lighter)

• volume (rich notes have more volume)

• frequency (high notes have a high frequency)

When the frequency of the man's pushing matches the swing's natural frequency, the amplitude will increase (the swing gets higher and higher). 

 

If the man randomly pushes the girl with a "too slow" or "too fast" frequency you will not see the girl swing higher and higher.

• true

• false

When the frequency of the sound wave matches the natural frequency of the wine glass, the wine glass will begin to vibrate.  Singing the note loudly and continuously will increase the amplitude of vibration until the amplitude is so great the glass breaks.

• true

• false

Glass is actually very strong.  What causes glass to lose it's strength.

• wine

• water

• very small microscopic cracks