Explain the processes of wave refraction and longshore drift. What happens to sand as a result of these processes?

Question

What will be an ideal response?

Answer 1

ANSWER: The part of each wave in shallower water near shore begins to drag on the bottom first and thus slows down; the part of the wave still in deeper water moves faster, so the crest of the wave curves around toward the shore. This is called wave refraction because waves bend, or refract, toward shore. When wave crests approach a beach at an angle, the breaking wave pushes the sand grains up the beach slope at an angle to the shore. As the wave then drains back into the sea, the water moves directly down the beach slope perpendicular to the water's edge. Thus, grains of sand follow a looping path up the beach and back toward the sea. With each looping motion, each sand grain moves a little farther along the shore. The angled waves thus create a longshore drift that essentially pushes a river of sand along the shore near the beach.?