Unit 8 Waves

Main Questions

1. What are waves?
2. What causes waves?
3. Where do waves get there energy and where do waves release their energy?
4. What causes tsunamis?

Main Concepts

I.  Waves are moving energy
II. Disturbing forces cause waves
      A.  Wind blowing across water creates most waves in ocean
      B.  Movement of fluids with different densities (within fluid)
      C.  Mass movement into ocean (landslide, calving icebergs)
      D.  Seafloor movement
      E.  Gravitational attraction among Earth, Moon, and Sun
      F.  Human activities
III.  How waves move
      A.  Waves transmit energy through matter. Types:
            1.  Longitudinal (animation by Dan Russell)
            2.  Transverse(animation by Dan Russell )
            3.  Orbital-both longitudinal and transverse (Animation by Dan Russell)
IV.  Wave characteristics
      A.  Idealized sine wave
            1.  Crest, trough, amplitude
            2.  Wavelength
            3.  Wave steepness (H/L)
            4.  Frequency
      B.  Circular orbital motion
            1.  Diameter equal to wave height
            2.  Diameters decrease with depth
            3.  Wave base (1/2 L)
      C.  Deep-water waves
            1.  Water depth is greater than wave base
            2.  Wave speed (celerity) is proportional to wavelength
      D.  Shallow-water waves
            1.  Water depth is less than 1/20 wave base
            2.  Friction with seafloor reduces speed
            3.  Wave speed (celerity) is proportional to depth
            4.  Orbital motion is flattened
      E.  Transitional waves
            1.  Characteristics of deep- and shallow-water waves
            2.  Water depth is 1/2 to 1/20 wave base
            3.  Wave speed depends on both wavelength and depth
V.  Wind-generated waves determined by fetch
      A. Capillary waves
      B. Gravity waves
      C.  Swell
      D. Interference
            1.  Constructive interference (waves in phase)
            2.  Destructive interference (waves out of phase)
            3.  Mixed interference
      E.  Rogue waves
      G.  Surf
      H.  Wave diffraction, reflection, and refraction

VI. Tsunami or seismic sea wave
      A.  Sudden changes in seafloor topography
      B.  Long wavelength, fast speed in open ocean
      C.  Near the shore tsunami causes ocean level to rise (or lower) dramatically
      D.  Tsunami warning system (Historic Tsunamis)

Vocabulary

gravity wave, ripple, capillary wave, crest, trough, wavelength, wave height (amplitude), wave period, orbit, deep-water wave, frequency, progressive wind wave, forced wave, free wave, swell, fetch, wave steepness, shallow-water wave, diffraction, breaker, rip current, tsunami, standing wave, node, antinode, seiche, atmospheric wave, constructive interference, destructive interference, longitudinal wave, rogue wave, splash wave, surf zone, transverse wave

Schedule

• Week 27 Schedule
• Week 28 Schedule

Documents

1. The Biggest Wave Ever Recorded
2. Useable Wave Energy
3. Week 27 Quiz (Answers)
4. Large Waves Batter El Salvador, Mexico
5. Notebook Binder Check 8
6. Unit 8 Test Corrected

PowerPoints

• Waves PowerPoint
• Animation of Wave Motion and Diffraction (PC Only)

Quizzes

Self Check Quizes-Click on understanding the concepts or visualizing oceanography.

Links

1. Graphics
2. Virtual Labs and Simulations
3. Animation of water wave
4. Wind Swells and Rogue Waves (NOAA)
5. Tsunami Overview by Stephen Nelson at Tulane