Transverse and longitudinal waves — common mistakes

Always remember the core distinction: Transverse waves 'wiggle' perpendicular to energy flow, while longitudinal waves 'push-pull' parallel. This fundamental difference is key to understanding polarisation and predicting wave behaviour in exams.

The main difference lies in the direction of particle oscillation relative to the wave's energy transfer. In transverse waves, particles oscillate perpendicular to energy flow, while in longitudinal waves, they oscillate parallel to it.

Sound waves are longitudinal waves, meaning their particles oscillate back and forth parallel to the direction of wave propagation. Polarisation requires restricting oscillations to a single plane perpendicular to the direction of travel, which isn't possible for a longitudinal wave.

Waves transfer energy through the vibrations or oscillations of particles in a medium, or through oscillating fields in a vacuum (for EM waves). The particles themselves simply move back and forth about a fixed position, passing the energy along, rather than moving with the wave.