3. Aim: How do waves cause erosion? I. Wave – caused by wind A. The size of a wave is determined by wind speed, the length of time the wind blows in one direction and the distance the wind has blown across the water (fetch). B. Wave characteristics 1.Crest – top of wave 2.Trough – bottom of wave 3.Wavelength – distance from one crest to the next crest 4.Height – vertical distance from the trough to the crest

5. C. Wave motion 1. Water particles rise and fall in circular paths with little forward movement until the wave gets closer to the shore. 2. Surf – foaming water resulting from water breaking on the shore

8. D. Wave erosion 1. Breaking storm waves may strike rock cliffs with a force of thousands of kilograms per square meter a. May remove large boulders and wash away loose sand and clay.] b. Boulders fall and break up other rocks that they hit

9. 2. Results of shoreline erosion a.Sea cliff b.Stack c.Sea cave d.arches

13. 3. Water and sediments on a beach are moved by swash, backwash, longshore currents, and rip currents. a. Swash – motion of water up the beach c. Longshore current – water that moves parallel to the shore beyond the breakers b. Backwash – water that moves back down the beach under the next wave. (strong backwash is called an undertow).

14. d. Rip currents – strong surface currents that flow away from the beach.