This deep dive covers Sound as a Longitudinal Wave within Sound Waves for GCSE Physics. Revise Sound Waves in Waves for GCSE Physics with 13 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 2 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
🔊 Sound as a Longitudinal Wave
Sound is a longitudinal wave — air molecules vibrate back and forth in the same direction as the wave travels. This creates alternating regions:
- Compressions: regions where air molecules are pushed together (higher pressure)
- Rarefactions: regions where air molecules are spread apart (lower pressure)
Crucially, the air molecules themselves do NOT travel with the sound — they vibrate back and forth around a fixed average position. Only the pattern of pressure differences (the wave) moves forward. This is why your ears detect sound even when you're far from the source — the pattern of compressions travels all the way to you.
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.