Joby drives one end of a stretched cord with slow, steady shakes until one wide loop swings between the ends. Then he shakes faster. The one-loop pattern breaks, and at a higher frequency a clean two-loop pattern appears.
One cord can hold many different patterns. They form a ladder, and the ladder has names.
At the lowest frequency that makes a standing wave, the cord swings as a single loop between its ends.
This lowest pattern is called the fundamental.
Shaking faster, the next clean pattern has two loops and one more node, and it appears at a greater frequency.
Each harmonic up the ladder has more nodes than the pattern below it.
Each harmonic up the ladder also forms at a greater frequency than the pattern below it.
The ladder is the cord's own: each pattern appears only at its own frequency, the way a plucked string always rings at its natural frequency.
On one cord, Ilka sees a three-loop pattern at one frequency and a five-loop pattern at another. Which pattern formed at the greater frequency?
More loops means more nodes, so the five-loop pattern sits higher on the ladder.
Higher patterns form at greater frequencies.
The five-loop pattern.
Which pattern of any cord is its fundamental?
The fundamental is the lowest pattern of the ladder.
The single-loop pattern, formed at the lowest standing-wave frequency.
A cord can hold a one-loop, a two-loop, and a three-loop standing wave. Which one is the fundamental?
Kerstin's cord steps from a two-loop pattern up to a three-loop pattern. How does the new pattern's frequency compare with the old one's?
Lazlo says: 'Every harmonic of a cord forms at a greater frequency than the fundamental.' Is Lazlo correct?
What is a cord's fundamental?
On one wire, which standing-wave pattern forms at the greatest frequency?
Compared with the fundamental, every harmonic of a cord has...