NOTES

When studying waves, it is important to note that while it appears the water is moving forward, only a small amount of water is actually moving. Instead, it is the wave’s energy that is moving and since water is a flexible medium for energy transfer, it looks like the water itself is moving. In the open ocean, the friction moving the waves generates energy within the water. This energy is then passed between water molecules in ripples called waves of transition. When the water molecules receive the energy, they move forward slightly and form a circular pattern.

As the water’s energy moves forward toward the shore and the depth decreases, the diameter of these circular patterns also decreases. When the diameter decreases, the patterns become elliptical and the entire wave’s speed slows. Because waves move in groups, they continue arriving behind the first and all of the waves are forced closer together since they are now moving slower. They then grow in height and steepness. When the waves become too high relative to the water’s depth, the wave’s stability is undermined and the entire wave topples onto the beach forming a breaker.

Breakers come in different types - all of which are determined by the slope of the shoreline. Plunging breakers are caused by a steep bottom; and spilling breakers signify that the shoreline has a gentle, gradual slope.The exchange of energy between water molecules also makes the ocean crisscrossed with waves traveling in all directions. At times, these waves meet and their interaction is called interference, of which there are two types. The first occurs when the crests and troughs between two waves align and they combine. This causes a dramatic increase in wave height. Waves can also cancel each other out though when a crest meets a trough or vice-versa. Eventually, these waves do reach the beach and the differing size of breakers hitting the beach is caused by interference farther out in the ocean.