Resonance

Most recent answer: 10/22/2007

Q:
What is Resonance?
- Shea
Sacramento, Ca. USA
A:
Dear Shea,

In technical language, resonance occurs when the force driving an oscillating object varies at the same frequency, conveniently called the "resonant frequency", that the object would naturally oscillate at.

To figure out what this means, think about a pendulum swinging in front of you. Watch it swing for a while, then start giving it little pushes at random times and in random directions. What will happen? Sometimes it will swing, other times you’ll stop it, but it will never get very far. Now, instead of pushing randomly, every time it starts a swing, help it along by pushing it in the same direction. The amplitude of the swings will get large very quickly. That is because the force you are applying to the pendulum is in RESONANCE with its natural swinging frequency.

The exact same thing happens when you swing on a swing. If you pump your legs in time with the swing’s motion, you achieve resonance, and you swing higher.

MG

(published on 10/22/2007)