## Frequency Measures Patterned, Periodic Repetitions - A sound is periodic if it contains air pressure fluctuations that steadily repeat in a pattern - If a sound is periodic it has a frequency, which is a measurement for how often the pattern repeats per second - Frequency is measured in Hertz (Hz) - Hertz = amount of repeated patterns per second - ![[21. Nakul/_attachments/image.png|463x386]] The top waveform displays a pattern that repeats itself **more frequently** throughout a one-second timeframe. This repetition occurs slightly more than 11 times every second, indicating that the frequency of the waveform is just above 11 Hz. In contrast, the bottom waveform features a pattern that recurs **less frequently** within the same one-second period. This pattern repeats itself slightly less than two times per second, leading to a conclusion that its frequency is slightly below 2 Hz.