Erosion by Waves

Erosion By Waves

Waves constantly crash against coastlines, slowly wearing away rock and soil. This process is called wave erosion. Strong waves can break apart cliffs, carve out sea caves, and remove sand from beaches. Over time, wave erosion can create new coastal landforms such as sea arches, sea stacks, and wave-cut cliffs. The power of wave erosion depends on factors like wave strength, wind speed, and the type of rock along the shore. These changes may happen slowly, but over the years and decades, waves can dramatically reshape coastlines.

Science and Engineering Practice (SEP): Constructing Explanations and Designing Solutions

Constructing explanations for wave erosion involves studying coastal features, wave energy, and the materials that make up the shoreline. Scientists collect evidence from field observations, aerial photos, and erosion rate measurements to explain how and why coastal landforms change over time. These explanations are built on reliable evidence and natural laws that describe how water and wind interact with rock. Understanding wave erosion also helps in designing solutions, such as sea walls or vegetation barriers, to protect coastal areas from damage.

Activity Ideas:

• Wave erosion model: Use a tray filled with sand or clay and create waves using your hand or a paddle. Observe how the “shoreline” changes over time with repeated wave action.
• Coastline comparison: Study photos of different coastal areas, some rocky, some sandy, and identify how wave erosion has shaped each. Discuss how rock type and wave energy affect erosion.

Crosscutting Concept (CCC): Scale, Proportion, and Quantity

• Scale: Wave erosion occurs across different scales. While a single wave may move only a few grains of sand, repeated wave action over many years can wear down large rock formations and reshape entire coastlines.
• Proportion: The size and energy of waves, combined with the strength of the wind and the type of rock or soil on the coast, influence how quickly erosion happens. Small increases in wave force can lead to much greater amounts of erosion.
• Quantity: Scientists measure the amount of material removed by wave action and the rate at which coastlines retreat. These quantities help explain how coastal landscapes change and allow predictions about future shoreline movement.