Waves and Tides: Transmission of Energy through Matter

1. Chapter 10 Waves and Tides

2. Waves • Transmission of energy through matter • Parts of a wave: • Crest • Trough • Height • Wavelength • Period • Frequency

3. Wave Parts

4. Three Types of Waves • Longitudinal • Occurs when matter moves back and forth in the same direction that the energy travels • Move through all states of matter • Ex. Sound • Transverse • Move through matter • Motion is perpendicular to the direction in which the wave as a whole is moving

5. Three Types of Waves • Orbital waves • Only transmit through fluids • Occur when energy moves the fluid in a circular motion as it passes • Ex. Buoy on the water

6. Causes • Disturbing forces • Restoring forces • Interaction between these two forces give waves their characteristics

7. Disturbing Forces • Wind is the most common • Changes in gravity cause the tides. • Seismic activity create tsunamis.

8. Restoring Forces • Gravity • Main restoring force for large waves and seismic waves • Gravity and the Coriolis effect • Main restoring force for the tides • Surface tension • Restoring force for capillary waves

9. Capillary Waves • Classified as such because the primary force countering them is surface tension • First to form • Small waves

10. Gravity Waves • Gravity= the weight of the wave • Large waves

11. Deep water waves • Occur in water that is deeper than half their wavelength • Water motion decreases rapidly with depth • Not affected by ocean bottom

12. Shallow water waves • Water is shallower than one-fourth the wavelength • The ocean bottom creates drag that affects the orbital motion

14. Wave size • Three factors affect wave size • Wind speed- how fast the wind blows • Wind duration- Length of time the wind blows • Fetch- Surface area over which the wind blows

15. Internal Waves • Waves can move inside the ocean • Occur within different density layers • Can be more than 30 meters tall • Move slowly

16. Breakers • Three types • Plunging • Characterized by a curl as the top of the wave pitches through the air before splashing into the bottom • Occur on moderately steep beaches • Spilling • Occur on gently slope beaches • Top of the wave tumbles and slides down the front of the waves it decelerates slowly.

17. Breakers • Surging • Occur on very steep beaches • Little or no bottom contact

19. Storm Surge • A destructive wave that forms when high winds push water against the shore, where it piles up • The shallower the water offshore, and the further it extends offshore the greater the surge • U.S. Gulf Coast has the greatest storm surge

20. Storm Surge • Only exists in a cyclonic storm • Accounts for about 90% of deaths in a hurricane

21. Tsunamis • Caused by sudden water displacement by • Earthquakes • Volcanic eruptions • Landslides • Icebergs falling into the sea • Also called tidal waves

22. Tsunamis • All shallow water waves • Fast moving waves that can travel thousands of kilometers • Not an issue on the open sea • Becomes larger as it reaches shore • Wave builds as it reaches the shore • Wave energy is pushed up in shallow water

24. Tides • Daily variations in the ocean’s levels • Most noticeable at the shore • Result from the gravitational pull of the moon and the sun • Moon has more influence

25. Types of Tides • Three types • Diurnal • One high and one low tide daily • Occur in the Gulf of Mexico • Semidiurnal • Two high and two low tides daily • East Coast of the U.S. • Mixed • Two unequal high and low tides daily • Pacific coast of the U.S.

26. Influence of the Sun and Moon • Moon has 2x the influence of the sun • Spring tides • Occur when the sun, moon, and Earth are aligned • Happens on new and full moon phases • Causes highest and lowest tides • Neap tides • Sun and moon form right angle to the Earth • Lowers the high tide and raises the low tide • Moon is in quarter phases