Movement of Water in the Oceans
What are Ocean Waves?
 Ocean Waves are the large scale movement of energy
through water molecules.
 The wave energy moves forward, the molecules don’t.
They just move in a circular motion
 Think of surfers waiting for a wave, they bob up and
down, but don’t travel forward as a wave (and its
energy) passes beneath them.
 They have to kick, paddle, or be towed into a wave to
ride it.
http://www.cleanvideosearch.com/media/action/yt/watch?v=7yPTa8qi5X8
Video of circular motion of a water molecule, it appears to just bob up and down.
How do ocean waves form?
 Most waves develop on the surface of the water by a
disturbance such as wind.
 Friction between the air and water causes the wind to
pull the water upward while gravity works to pull the
water back down.
Wave height
 Wave height is determined by three things
 How long the wind has been blowing
 How much open water the wind is blowing across (fetch)
 The speed of the wind
http://www.pbs.org/wnet/savageseas/multimedia/wavemachine.html
Making waves interactive simulator
 Fetch is happening!
Breaking waves
 Eventually a wave stops growing in size, and it will
break.
 When waves approach shore the water depth decreases
and the wave will start feeling the bottom.
 As the wave feels the bottom, the circular loops of
water motion change to elliptical shapes, as loops are
deformed by the bottom.
 Eventually the steep front portion of wave cannot
support the water as the rear part moves over, and the
wave breaks.
 Review of the formation of a wave
http://video.search.yahoo.com/video/play;_ylt=A2KLqIV2dIZTlxIA5UT7w8QF;_ylu=X3oDMTByNDY3bGRuBHNlYwNzcgRzbGsDdmlkBHZ0aWQDBGdwb3MDNQ-?p=how+does+an+ocean+wave+form&vid=76910b320e5d940b90f90547a11fa9b8&l=2%3A44&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DVN.608
055962120294038%26pid%3D15.1&rurl=http%3A%2F%2Fchannel.nationalgeographic.com%2Fchannel%2Fvideos%2Fdevelopment-of-oceanwaves%2F&tit=Development+of+Ocean+Waves&c=4&sigr=12go7cnld&sigt=10qelggjb&pstcat=arts+culture+and+entertainment&age=0&fr=mcafee&tt=b
You can use your knowledge of science
(weather and wave formation) to find the
perfect surf spot!
Why are waves usually larger on
the west coast?
 More fetch
 Prevailing
westerlies
wind pattern
 Sudden
reduction of
water depth
Parts of a wave
 Crest – High point
 Trough – Low point
 Wave height –
Distance from crest to
trough
 Wavelength –
Distance between
crests
Parts of an ocean wave
Wavelength(λ)
Crest
Amplitude
Trough
Wave Height
Special Waves
 Tsunamis:
 Giant waves caused by seismic activity
 Most damaging waves travel over great distances
 Tsunami waves lose very little energy in the open water
 When encountering the shoreline, friction quickly slows
the bottom of the wave, allowing water to rise quickly
 Tsunami waves do not have to be tall to be damaging,
the surge of the amount of water is the issue!
Tsunamis form when energy from an
underwater earthquake moves the water,
rather than wind energy at the surface.
Tsunamis
 The wave
will
continue
until it hits
land
Some of the wave energy even
reached the US.
 Storm Surge
 A high water event associated with significant low pressure
weather disturbances (hurricane, topical storms, etc.)
 Low Pressure systems allow sea levels to rise (high pressure
depresses sea level)
 High winds push water inland
Storm Surge
 “Rogue” Waves:
 Greater than twice the size of surrounding waves
 Unpredictable, may approach from opposite direction of
normal waves
 Steep sided with deep troughs
http://channel.nation
algeographic.com/cha
nnel/aliendeep/videos/roguewaves/?source=search
video
 Rogue wave in
the
Mediterranean
in 2010
Surfing waves
http://www.youtube.com/watch?v=26KzUnEbTUs
Surfing one of the world’s heaviest waves
http://www.oceanweather.com/data/
Look up current wave height data in different regions of earth
http://www.youtube.com/watch?v=5_HefhiwioE
wave formation, slow but good visual explanation 3 min
Is the motion of the water caused
by waves, currents, or tides?
 A review quiz
1. Water levels are higher than
normal during a full moon.
Wave
Current
Tide
2. A tsunami
Wave
Current
Tide
3. A constant flow of cold water
from Alaska travels all the way to
California
Wave
Current
Tide
4. Water moving an iceberg from
Greenland to the N. Atlantic
Wave
Current
Tide
5. A ring of moving water in a
swimming pool after your friend
does a cannonball in the deep end.
Wave
Current
Tide
6. “Rivers” of water that flow in a
specific direction.
Wave
Current
Tide
7. Large, movement of water in a
circular path called a gyre
Wave
Current
Tide
8. In oceans, the movement of
energy through the water
Wave
Current
Tide
9. Water moving due to differences
in density (cold and salty will sink)
Wave
Current
Tide
10. These depend on the wind
speed, distance wind traveled, and
how long the wind was blowing
Wave
Current
Tide
11. Type of water movement that
can influence a local climate.
Wave
Current
Tide
12. The large scale movement of
water due to wind
Wave
Current
Tide
13. Movement of water due to the
moon and sun’s gravitational pull
Wave
Current
Tide
14. Water in the Northern
Hemisphere moves in a clockwise
direction due to the Coriolis effect.
Wave
Current
Tide
15. The up and down movement of
water levels
Wave
Current
Tide
16. Water motion pictured below:
Wave
Current
Tide
17. Water motion pictured below:
Wave
Current
Tide
18. Water motion pictured below:
Wave
Current
Tide