What is the path followed by a sand grain from a succession of waves impinging obliquely onto a beach?
A) A sawtooth path, driven obliquely up the beach face with the swash then straight down the beach face with the backwash.
B) Perpendicular to the wave front, obliquely up the beach on the swash, then reflected out at an opposite but equal angle with the backwash.
C) A path parallel to the beach, but well offshore as sand is only moved by longshore currents not by breaking waves.
D) A straight path, right at the shoreface, pushed along parallel to the beach by the breaking wave.

Question

Quizplus · Accepted Answer

A sawtooth path is created as the sand grain is driven obliquely up the beach face with the swash (the forward movement of a wave up a beach) and then moves straight down the beach face with the backwash (the water returning to the ocean after a wave has broken). This pattern results from the combination of the wave's oblique approach and the gravitational pull directing the backwash perpendicularly down the slope of the beach.

What Is the Path Followed by a Sand Grain from a Succession