2. Ocean Waves and Tides

3. Waves A Wave is a rhythmic movement that carries energy through matter or space. A Wave is a rhythmic movement that carries energy through matter or space. In oceans, waves move through seawater In oceans, waves move through seawater

5. Waves Caused by: Wind Wind Earthquakes Earthquakes Gravitational force of the Moon and Sun. Gravitational force of the Moon and Sun.

6. Parts of a Wave Crest – highest point of a wave Crest – highest point of a wave Trough – lowest point of a wave Trough – lowest point of a wave Wave Height – vertical distance between the crest and the trough Wave Height – vertical distance between the crest and the trough Wavelength – horizontal distance between two crests or two troughs Wavelength – horizontal distance between two crests or two troughs

7. Wavelength Wave Height Crest Trough Still Water Wave Parts

8. Wave Formations Form when energy is transferred from a source to the ocean water Form when energy is transferred from a source to the ocean water Most common from WIND Most common from WIND

9. Wave Movement When a wave passes through the ocean, individual water molecules move up and down but they do not move forward or backward. When a wave passes through the ocean, individual water molecules move up and down but they do not move forward or backward. Water does NOT travel with waves Water does NOT travel with waves

11. Wave Movement When a wave breaks against the shore, the crest outruns the trough and the crest collapses. When a wave breaks against the shore, the crest outruns the trough and the crest collapses. Called a breaker. Called a breaker. In this case, water does move forward and backward. In this case, water does move forward and backward.

12. Wave energy Wind keeps adding more energy to waves Wind keeps adding more energy to waves WIND SPEED: WIND SPEED: –-Wave period is time between 2 wave crests or 2 wave troughs –-Speed of wave= wave length/wave period

13. Waves reaching Shore Most waves reach shore and transfer energy to beach Most waves reach shore and transfer energy to beach

14. Why Waves Break The ocean floor slows the bottom of the wave, yet the top is moving at original speed The ocean floor slows the bottom of the wave, yet the top is moving at original speed Breaker is when wave’s crest crash on shore Breaker is when wave’s crest crash on shore

16. Waves Caused by Wind When wind blows across a body of water, friction causes the water to move along with the wind. When wind blows across a body of water, friction causes the water to move along with the wind. Wave Height depends on – Wave Height depends on – –Wind speed –Distance over which the wind blows –Length of time the wind blows

20. Tides The rise and fall in sea level is called a tide. The rise and fall in sea level is called a tide. Caused by a giant wave. Caused by a giant wave. One low-tide/high-tide cycle takes about 12 hrs and 25 min. One low-tide/high-tide cycle takes about 12 hrs and 25 min. Tidal range is the difference in ocean level between high-tide and low-tide Tidal range is the difference in ocean level between high-tide and low-tide

21. What is the Tidal Range? HT = 30 ft, LT = 20 ft HT = 30 ft, LT = 20 ft HT = 20 ft, LT = 12 ft HT = 20 ft, LT = 12 ft HT = 50 ft, LT = 20 ft HT = 50 ft, LT = 20 ft

22. Tidal Range The tidal range is the difference between the level of the ocean at high tide and low tide. The tidal range is the difference between the level of the ocean at high tide and low tide.

23. Why Tides Happen Moon’s gravity pulls on every particle of Earth Moon’s gravity pulls on every particle of Earth Moon’s pull decrease with increase in distance Moon’s pull decrease with increase in distance Areas closer to the moon have stronger pull Areas closer to the moon have stronger pull Liquids are pulled more easily by gravity Liquids are pulled more easily by gravity

25. Where Tides Happen Area of ocean that directly faces moon is pulled most Area of ocean that directly faces moon is pulled most Area furthest from moon has little effect from moon’s pull Area furthest from moon has little effect from moon’s pull Ocean water bulges toward moon Ocean water bulges toward moon

26. Gravitational Effect of the Moon Two big bulges of water form on the Earth: Two big bulges of water form on the Earth: –one directly under the moon –another on the exact opposite side As the Earth spins, the bulges follow the moon. As the Earth spins, the bulges follow the moon.

29. High tides and Low tides High tide- bulges that form as a result of moon—Ocean level is higher than normal High tide- bulges that form as a result of moon—Ocean level is higher than normal Low tide- water is pulled toward opposite area where high tide is occurring Low tide- water is pulled toward opposite area where high tide is occurring Each day usually has 2 high tides and 2 low tides Each day usually has 2 high tides and 2 low tides

30. Timing of Tide Moon revolves around earth slower than earth rotates Moon revolves around earth slower than earth rotates Takes 24 hours 50 min to rotate to face the moon again Takes 24 hours 50 min to rotate to face the moon again High tides and low tides happen 50 minutes later each day High tides and low tides happen 50 minutes later each day

31. Tidal Variations Sun has gravitational pull but far, when sun and moon pull together- greater tide Sun has gravitational pull but far, when sun and moon pull together- greater tide Spring Tides Spring Tides –Earth, Moon, and Sun are lined up –High Tides are higher and Low Tides are lower than normal –During new moon and full moon

32. Spring TIDES

34. Neap Tides Neap Tides –Earth, Moon, and Sun form right angles –High Tides are lower and Low Tides are higher than normal –During different phases of moon

35. NEAP Tides Neap tides are especially weak tides. Neap tides are especially weak tides. Moon & Sun are perpendicular to each other. Moon & Sun are perpendicular to each other. Moon & the Sun’s gravity cancel each other out. Moon & the Sun’s gravity cancel each other out.

37. Mont St. Michel A great example of tidal surge is the castle Mont St. Michel in France. A great example of tidal surge is the castle Mont St. Michel in France. The tides surrounding the “Mount” can vary by 14 meters between high and low tides, and move in as rapidly as 1 meter a second. The tides surrounding the “Mount” can vary by 14 meters between high and low tides, and move in as rapidly as 1 meter a second. The “Mount” is connected to the mainland by a thin natural land bridge, which before modernization was covered by the sea at high tide, and revealed during the low tide. The “Mount” is connected to the mainland by a thin natural land bridge, which before modernization was covered by the sea at high tide, and revealed during the low tide.

38. The End