Waves

1. Waves Movement of Water in the Oceans

2. What are Ocean Waves? • Ocean Waves are the large scale movement of energy through water molecules. • The wave energy moves forward, the molecules don’t. They just move in a circular motion

3. Think of surfers waiting for a wave, they bob up and down, but don’t travel forward as a wave (and its energy) passes beneath them. • They have to kick, paddle, or be towed into a wave to ride it. http://www.cleanvideosearch.com/media/action/yt/watch?v=7yPTa8qi5X8 Video of circular motion of a water molecule, it appears to just bob up and down.

4. How do ocean waves form? • Most waves develop on the surface of the water by a disturbance such as wind. • Friction between the air and water causes the wind to pull the water upward while gravity works to pull the water back down.

5. Wave height • Wave height is determined by three things • How long the wind has been blowing • How much open water the wind is blowing across (fetch) • The speed of the wind http://www.pbs.org/wnet/savageseas/multimedia/wavemachine.html Making waves interactive simulator

7. Fetch is happening!

8. Breaking waves • Eventually a wave stops growing in size, and it will break.

9. When waves approach shore the water depth decreases and the wave will start feelingthe bottom. • As the wave feels the bottom, the circular loops of water motion change to elliptical shapes, as loops are deformed by the bottom. • Eventually the steep front portion of wave cannot support the water as the rear part moves over, and the wave breaks.

10. Review of the formation of a wave http://video.search.yahoo.com/video/play;_ylt=A2KLqIV2dIZTlxIA5UT7w8QF;_ylu=X3oDMTByNDY3bGRuBHNlYwNzcgRzbGsDdmlkBHZ0aWQDBGdwb3MDNQ--?p=how+does+an+ocean+wave+form&vid=76910b320e5d940b90f90547a11fa9b8&l=2%3A44&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DVN.608055962120294038%26pid%3D15.1&rurl=http%3A%2F%2Fchannel.nationalgeographic.com%2Fchannel%2Fvideos%2Fdevelopment-of-ocean-waves%2F&tit=Development+of+Ocean+Waves&c=4&sigr=12go7cnld&sigt=10qelggjb&pstcat=arts+culture+and+entertainment&age=0&fr=mcafee&tt=b

11. You can use your knowledge of science (weather and wave formation) to find the perfect surf spot!

12. Why are waves usually larger on the west coast? • More fetch • Prevailing westerlies wind pattern • Sudden reduction of water depth

13. Parts of a wave • Crest – High point • Trough – Low point • Wave height – Distance from crest to trough • Wavelength – Distance between crests

14. Parts of an ocean wave

15. Special Waves • Tsunamis: • Giant waves caused by seismic activity • Most damaging waves travel over great distances • Tsunami waves lose very little energy in the open water • When encountering the shoreline, friction quickly slows the bottom of the wave, allowing water to rise quickly • Tsunami waves do not have to be tall to be damaging, the surge of the amount of water is the issue!

16. Tsunamis form when energy from an underwater earthquake moves the water, rather than wind energy at the surface.

17. Tsunamis • The wave will continue until it hits land

18. Some of the wave energy even reached the US.

19. Storm Surge • A high water event associated with significant low pressure weather disturbances (hurricane, topical storms, etc.) • Low Pressure systems allow sea levels to rise (high pressure depresses sea level) • High winds push water inland

20. Storm Surge

22. “Rogue” Waves: • Greater than twice the size of surrounding waves • Unpredictable, may approach from opposite direction of normal waves • Steep sided with deep troughs http://channel.nationalgeographic.com/channel/alien-deep/videos/rogue-waves/?source=searchvideo

23. Rogue wave in the Mediterranean in 2010

24. Surfing waves http://www.youtube.com/watch?v=26KzUnEbTUs Surfing one of the world’s heaviest waves http://www.oceanweather.com/data/ Look up current wave height data in different regions of earth

25. http://www.youtube.com/watch?v=5_HefhiwioE wave formation, slow but good visual explanation 3 min

26. Is the motion of the water caused by waves, currents, or tides? • A review quiz

27. 1. Water levels are higher than normal during a full moon. Wave Current Tide

28. 2. A tsunami Wave Current Tide

29. 3. A constant flow of cold water from Alaska travels all the way to California Wave Current Tide

30. 4. Water moving an iceberg from Greenland to the N. Atlantic Wave Current Tide

31. 5. A ring of moving water in a swimming pool after your friend does a cannonball in the deep end. Wave Current Tide

32. 6. “Rivers” of water that flow in a specific direction. Wave Current Tide

33. 7. Large, movement of water in a circular path called a gyre Wave Current Tide

34. 8. In oceans, the movement of energy through the water Wave Current Tide

35. 9. Water moving due to differences in density (cold and salty will sink) Wave Current Tide

36. 10. These depend on the wind speed, distance wind traveled, and how long the wind was blowing Wave Current Tide

37. 11. Type of water movement that can influence a local climate. Wave Current Tide

38. 12. The large scale movement of water due to wind Wave Current Tide

39. 13. Movement of water due to the moon and sun’s gravitational pull Wave Current Tide

40. 14. Water in the Northern Hemisphere moves in a clockwise direction due to the Coriolis effect. Wave Current Tide

41. 15. The up and down movement of water levels Wave Current Tide

42. 16. Water motion pictured below: Wave Current Tide

43. 17. Water motion pictured below: Wave Current Tide

44. 18. Water motion pictured below: Wave Current Tide