1. Ocean Waves and Tides

2. 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

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

5. 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

6. Wavelength Wave Height Crest Trough Still Water Wave Parts

7. 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.

9. How to find the speed of a specific wave Wave length (m) / wave period (s) = wave speed in m/s

10. Sample problem If a wave has a wavelength of 10 M and takes 5 sec. to move a specific distance what is the wave speed? If a wave has a wavelength of 10 M and takes 5 sec. to move a specific distance what is the wave speed?

11. Tide’s There are 4 tides per day (24 hours) There are 4 tides per day (24 hours) 2 high tides 2 high tides 2 low tides 2 low tides A tide cycle happens approx. every 6 hours A tide cycle happens approx. every 6 hours

12. Sample problem If sandy is at the beach and low tide is coming in at 9:35 AM, when is the next High Tide? Low tide? If sandy is at the beach and low tide is coming in at 9:35 AM, when is the next High Tide? Low tide?

13. 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.

15. 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

19. Tides The rise and fall in sea level is called a tide. The rise and fall in sea level is called a tide. 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

20. 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

21. 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.

23. Gravitational Effect of the Sun Spring Tides Spring Tides –Earth, Moon, and Sun are lined up –High Tides are higher and Low Tides are lower than normal

25. Gravitational Effect of the Sun Neap Tides Neap Tides –Earth, Moon, and Sun form right angles –High Tides are lower and Low Tides are higher than normal

27. HW Page 377. Questions 1-4