Note: Although this video reflects the GCSE curriculum, it includes some old misconceptions that differ from how geographers currently understand wave processes. We thank Prof Gerd Masselink for his guidance in this respect, which we summarise here:

The main problem is the assumption that a certain type of wave (large height and short period) is destructive and vice-verse. In fact, whether a beach erodes or accretes depends primarily on how current wave conditions compare with wave conditions in the preceding weeks/months. A beach generally seeks an equilibrium with the wave conditions and, although it may never quite reach this, is always seeking to do so. For example, at the end of the summer, the beach is closest to equilibrium with the summer wave conditions (whatever they are). Then, when a wave condition occurs that significantly deviates from the preceding conditions, the beach will respond. If the wave condition is more energetic, the beach is likely to erode mainly through the action of undertow in the surf zone.

We are working to update this video, in line with current understanding.

Related videos

Course links: GCSE • IGCSE • A-level • IA-level • IB Geography

Wave types and characteristics.

  • Destructive waves
  • Constructive waves
  • Fetch