Idea 6of 6Builds onEverything has a beat
Pushing on time
A small push, repeated. Why does the swing grow?
Today you'll discover
- why a tiny push can build a huge swing
- what timing has to do with it
- why a mistimed push undoes itself
Think firstA hand pushes the string gently, again and again
The push is small. Can the swing grow large?
Decide first, then press Next. Watch whether the envelope grows or stays small.
A string between two posts with a small arrow at the left end for the hand's push, and a faint envelope for the swing. After a prediction, the frames advance with the push in step and the envelope grows wider each time; then the push is mistimed and the envelope stays narrow. The last step asks what shatters a wine glass.
See the whole ideathe big idea and the key word, in one place
The big idea
A push on time compounds: resonance at the natural frequency.
Easy to get wrongResonance is not volume. A loud push at the wrong frequency does nothing lasting. A small push at the right one builds without limit.
Key word
- resonance
- the large build-up of vibration when a periodic push matches an object's natural frequency
About this modelOnly wavelengths that fit the length survive; the rest cancel within a few reflections.
Only wavelengths that fit the length survive; the rest cancel within a few reflections.
Ready to use it?
- Explain a described resonance by naming the natural frequency and the matched push.