Don't forget to check the blog for videos that reinforce the concepts in your notes!

1. Waves

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What makes waves?
Ship wakes
Animal movements
Tsunami
Most commonly: Wind

3. Wave Diagram (yes, you need to draw this)

4. Wave vocabulary
• Crest: Highest point of a wave
• Trough: Lowest point of a wave
• Wavelength: horizontal distance between either
two crests or two troughs
• Wave height: vertical distance between one crest
and the next trough (or vice versa)

5. Wave Vocabulary cont.
• Wave period: the time it takes two crests (or
two troughs) to pass a particular point
• Wave frequency: how often a number of
waves pass a given point in a particular
amount of time

6. What determines the size of a wave?
• The strength of the wind
• The duration the wind has been blowing
• The distance over which the wind travels (Fetch)

7. Deep Water Waves
• Do not “Feel” bottom
• Individual water molecules travel in an orbital
motion
• These waves are in water greater than ½ their
wavelength

8. Shallow Water Waves
• Feel bottom
• Move toward land
• These waves are in water shallower than
1/20th their wavelength
• As they reach the shore, friction slows them
down, but they do become bigger

9. Deep Water vs. Shallow Water Waves

10. Deep Water Waves vs.
Shallow Water Waves
The Wave
Breaks

11. Three Types of Shallow Water Waves
• Surging breakers are
considered destructive
to beaches
• Plunging breakers
frequently form
tunnels (surfers love
these)
• Spilling breakers are
gentle and break far
from shore

12. Summer Beach vs. Winter Beach
• Summer
waves more
gentle,
constructive
• Winter
waves more
harsh,
destructive

13. Longshore Currents and Drift
• Caused by waves hitting the beach at an angle
• Carries sand along the shoreline
• http://www.youtube.com/watch?v=U9EhVa4MmEs

14. How humans deal with Longshore Drift
Groins or jetties are
sometimes used to
prevent the loss of
sand to beach homes.
Can you see a problem
for the houses
immediately on the
down current side of
the groin?

15. Rip Currents
–a potentially dangerous
result of Longshore Currents
racing back out to sea
http://www.onr.navy.mil/focus/ocean/motion/cu

16. Tsunami
• Shallow water waves that grow tall as they approach
the shore
• Caused by seismic activity: earthquakes, landslides,
volcanoes
• Largest one recorded was in Lituya Bay, AK (1,720’)

17. Rogue Waves
• Also known as “Freak” Waves
• When two wave crests combine, their height and
power is extremely huge
• Most famous rogue wave occurred to the USS
Ramapo (112’)

18. Storm Surge
• Rise in the ocean that is caused by strong winds
associated with a storm
• Above and beyond the normal high tide water line
• Typically causes flooding in coastal areas