Longitudinal wave: A wave in which particles vibrate parallel to the direction of wave travel, producing compressions and rarefactions.
Compression: A region in a longitudinal wave where particles are pushed together, creating higher pressure.
Rarefaction: A region in a longitudinal wave where particles are spread apart, creating lower pressure.
Ultrasound: Sound waves with a frequency above 20,000 Hz (above the upper limit of human hearing).
Amplitude (sound): The maximum displacement of air molecules from their rest position; greater amplitude = louder sound.
Frequency (sound): The number of compressions passing a point per second; higher frequency = higher pitch.
This definitions covers Key Definitions within Sound Waves for GCSE Physics. Revise Sound Waves in Waves for GCSE Physics with 16 exam-style questions and 15 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 7 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Practice questions for Sound Waves
What type of wave is sound?
Describe how a sound wave is produced and how energy is transferred by a longitudinal wave.