Waves approaching at right angles to the coast move material up the beach if the waves are constructive. Constructive waves have a long wavelength but low height. Destructive waves are closer together and higher. As they plunge on the beach they comb down material and flatten the beach gradient.
Waves breaking on a beach at an oblique angle move sand and shingle by the process of longshore drift. The breaking wave (the swash) moves material up the beach at an angle whilst returning water (backwash) moves the material back at right angles to the beach. The net effect is a longshore movement.
Offshore, the build up of water against the coastline creates a current parallel to the shore. Whilst it can only move sand-sized sediments, it is capable of moving tens of thousands of tonnes of sand per year.
A fantastic video to use in class. It is very clear, visually interesting and short - try to use clips like this rather than a 30 minute video - longer videos won't keep student interest.
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