1. The Hydrosphere

2. The Ocean in Motion
Waves

3. Waves Learning Objectives How are waves created and sustained?
What are the major parts of a wave?
What is actually moving as a wave passes?
How do waves change as they approach the shore?
How are tsunamis different from normal waves?

4. Waves
Waves are created by energy traveling along the interface between ocean and atmosphere (the surface.)
Waves derive their energy and motion from wind.
The major parts of a wave are:
the crest
the trough

5. Wave Measurements
Wave height is the distance between a trough (low point) and a crest (high point.)
Wave period is the time interval for one full wave to pass a fixed position. This is also referred to as the frequency of the wave.
Wavelength is the horizontal distance between successive crests (or troughs.)
Wave amplitude is the height from the centerline (still water level) of a wave to its crest.

6. Waves Wave height, length, and period depend upon: the wind speed
the length of time the wind blows

7. Fetch is the distance that the wind travels.
Waves
Fetch is the distance that the wind travels.

8. The waveform (energy) moves forward.
Waves
As the wave travels, the water passes energy along by moving in a vertical circle
The waveform (energy) moves forward.
At a depth of about one-half the wavelength, the movement of water particles becomes negligible (called the wave base.)

9. Changes That Occur When a Wave Moves Onto Shore
Figure 15.14

10. Tsunamis
Unlike regular waves that draw their energy from air movement, tsunamis are caused by violent undersea earthquakes.
Tsunamis are among the most destructive forces on earth – they can cause hundreds of thousands of deaths and untold property damage.

11. Waves Summary How are waves created and sustained?
… by energy traveling along the interface between ocean and atmosphere (the surface.)
Waves derive their energy, motion, and sustainability from wind.

12. What are the major parts of a wave?
Waves
Summary
What are the major parts of a wave?
the crest, trough, wave height, wave length, wave period, amplitude, wave base

13. Waves What is actually moving as a wave passes?
Summary
What is actually moving as a wave passes?
The water passes energy along by moving in a vertical circle.
The waveform (energy) moves forward.

14. How do waves change as they approach the shore?
Summary
How do waves change as they approach the shore?
When the wave base touches the ocean floor, the base moves more slowly than the crests, causing the wave to topple over forward, or “break.”

15. How are tsunamis different from normal waves?
Summary
How are tsunamis different from normal waves?
Tsunamis draw their energy from violent undersea earthquakes, whereas regular waves draw their energy from air movement (wind.)

16. The Ocean in Motion
Tides

17. Tides Learning Objectives What is a tide?
What are the different types of tidal patterns?
What causes tides?
What are the different types of tides?
Where is the largest tide on Earth found?
What is the Saltstraumen?

18. Tides are important physical forces in our ocean
Gravitational interactions between the sun, moon and earth are the primary causes of tides
Different positions of the sun and moon create two different types of tides: spring tides and neap tides
Tides play an important role in the life cycle of many marine organisms

19. What is a tide?
A tide is the periodic rise and fall of a body of water due to gravitational interactions between the sun, moon and Earth

20. Tidal patterns vary around the world
Some places have one low tide and one high tide per day (diurnal tides)
Other places have two high and low tides per day approximately equal in size (semidiurnal tides)
If the two high and low tides of a semidiurnal tide are unequal in size, they are call mixed semidiurnal tides
The US has examples of semidiurnal tides (East Coast), diurnal tides (some areas of the Gulf of Mexico) and mixed tides (Pacific Coast)
For complete technical accuracy, the type of day referred to in the definitions for diurnal, semidiurnal, and mixed (semidiurnal) tides is a lunar day (also referred to as a tidal day). A lunar day is 24 hours and 50 minutes compared to the typical solar day which is 24 hours. It refers to the time required for a spot on earth to make a full rotation from a specific location under the moon to the same location (under the moon). For a more in depth explanation of a lunar day, see (Accessed, May 2011).

21. Tidal extremes: The Bay of Fundy
The Bay of Fundy in Canada is known for its large tidal range (differences of over 50ft have been recorded!)
Photo: NASA
Photo:
Accessed: November 2010

22. Tidal extremes: The Bay of Fundy
The Bay of Fundy in Canada is known for its large tidal range (differences of over 50ft have been recorded!)
Low tide
High tide
Photo: NASA
Photo:
Accessed: November 2010

23. What causes tides?
The gravitational pull of the sun and the moon causes “bulges” on Earth that move as we rotate
Gravitational pull
“Bulge”
of Earth
Sun
Earth
Moon
Teacher’s Note: The slide labels the gravitational pull and bulge of the Earth as you advance the slide.

24. What causes tides?
The tide rises when coastline enters the bulge and falls when it rotates out
High tide

25. Different types of tide
Sun
Earth
Moon
Spring tides occur when the sun and moon are in a straight line
The tidal range is typically highest during spring tides

26. Different types of tide
Earth
Neap tides occur when the sun and moon form a right angle with Earth
Low tides are typically higher and high tides are lower
Why is the moon’s pull greater than the sun’s?
Teacher’s Note: Even though the sun is larger than the moon, the moon’s pull is always greater because the moon is much closer to the earth.
Sun
Moon

27. Figure 1: Tide predictions for Dauphin Island, 3/1/11
Water Level (ft)
Figure 1: Shows tidal predictions for Dauphin Island, AL 3/1/11 Local Standard Time (LST) – Data comes from station (
Y-axis shows water levels in feet and x-axis shows time in hourly increments over the course of a day
What time does the first low tide occur? (8:00 a.m.)
What time does the first high tide occur? (8:00 p.m.)
How many high tides and low tides occur? (one high tide and one low tide)
What type of tide do you think this is? (Diurnal)
Time

28. Figure 1 shows a diurnal tide: one high and one low tide
First high tide ~8pm
Water Level (ft)
Figure 1: Shows tidal predictions for Dauphin Island, AL 3/1/11 Local Standard Time (LST) – Data comes from station (
Y-axis shows water levels in feet and x-axis shows time in hourly increments over the course of a day
What time does the first low tide occur? (8:00 a.m.)
What time does the first high tide occur? (8:00 p.m.)
How many high tides and low tides occur? (one high tide and one low tide)
What type of tide do you think this is? (Diurnal)
First low tide ~8am
Time

29. Figure 2: Tide predictions for Woods Hole, MA, 8/25/10
Water Level (ft)
Figure 2: Shows tidal predictions for Woods Hole, MA 8/25/10 Local Standard Time (LST) – Data comes from station (
Y-axis shows water levels in feet and x-axis shows time in hourly increments over the course of a day
How many high tides are present? (2)
What times do they occur? (~9:00 a.m. and ~9:00 p.m.)
How many low tides are present? (2)
What times do they occur? (4:00 a.m. and 4:00 p.m.)
What is the tidal range (distance between high and low tide) for first high and low tide (round to nearest foot)? (2 feet)
What is the tidal range for the second high and low tide (round to nearest foot)? (2 feet)
What type of tide is this? (Semidiurnal – 2 high and low tides of about equal heights)
Time

30. Figure 2 shows a semidiurnal tide: two high and low tides of equal heights
First high tide ~9am
Second high tide ~9pm
Tidal range 2ft
Tidal range 2ft
Water Level (ft)
Figure 2: Shows tidal predictions for Woods Hole, MA 8/25/10 Local Standard Time (LST) – Data comes from station (
Y-axis shows water levels in feet and x-axis shows time in hourly increments over the course of a day
How many high tides are present? (2)
What times do they occur? (~9:00 a.m. and ~9:00 p.m.)
How many low tides are present? (2)
What times do they occur? (4:00 a.m. and 4:00 p.m.)
What is the tidal range (distance between high and low tide) for first high and low tide (round to nearest foot)? (2 feet)
What is the tidal range for the second high and low tide (round to nearest foot)? (2 feet)
What type of tide is this? (Semidiurnal – 2 high and low tides of about equal heights)
Second low tide ~4pm
First low tide ~4am
Time

31. Figure 3: Tide predictions for Seattle, WA (Puget Sound), 5/1/11
Water Level (ft)
Figure 3: Shows tidal predictions for Seattle, Washington (Puget Sound) 5/1/11 Local Standard Time (LST) – Data comes from station (
Y-axis shows water levels in feet and x-axis shows time hourly increments over the course of a day
How many high tides are present? (2)
What times do they occur? (~4:00 a.m. and ~6:00 p.m.)
How many low tides are present? (2)
What times do they occur? (11:00 a.m. and 11:00 p.m.)
What is the tidal range (distance between high and low tide) for first high and low tide (round to nearest foot)? (10 feet)
What is the tidal range for the second high and low tide (round to nearest foot)? (4 feet)
What type of tide is this? (Mixed Semidiurnal – 2 high and low tides of unequal heights)
Time

32. Figure 3 shows a mixed semidiurnal tide: two high and low tides of unequal heights
Second high tide ~6pm
First high tide ~4am
Tidal range 4ft
Tidal range 10ft
Second low tide ~11pm
Water Level (ft)
Figure 3: Shows tidal predictions for Seattle, Washington (Puget Sound) 5/1/11 Local Standard Time (LST) – Data comes from station (
Y-axis shows water levels in feet and x-axis shows time hourly increments over the course of a day
How many high tides are present? (2)
What times do they occur? (~4:00 a.m. and ~6:00 p.m.)
How many low tides are present? (2)
What times do they occur? (11:00 a.m. and 11:00 p.m.)
What is the tidal range (distance between high and low tide) for first high and low tide (round to nearest foot)? (10 feet)
What is the tidal range for the second high and low tide (round to nearest foot)? (4 feet)
What type of tide is this? (Mixed Semidiurnal – 2 high and low tides of unequal heights)
First low tide ~11am
Time

33. The Saltstraumen https://www.youtube.com/watch?v=Ci-uwzFIsgE
The Saltstraumen has the strongest tidal current in the world. Up to 520,000,000 cu. yd. of seawater forces its way through a 1.9 mile long and 490 foot wide strait every six hours, with water speeds reaching 25 mph. Vortices known as whirlpools (or maelstroms) up to 33 feet in diameter and 16 feet in depth are formed when the current is at its strongest. The Saltstraumen has existed for about two to three thousand years. Before that, the area was different due to post-glacial rebound. The current is created when the tide tries to fill the Skjerstadfjorden. The height difference between the sea level and the fjord inside can be up to 3 ft 3 in. When the current turns, there is a period when the strait is navigable.

34. A tide is the periodic rise and fall of a body of water.
Tides
Summary
What is a tide?
A tide is the periodic rise and fall of a body of water.

35. What are the different types of tidal patterns?
Tides
Summary
What are the different types of tidal patterns?
diurnal tides - one low tide and one high tide per day
semidiurnal tides - two high and low tides per day approximately equal in size
mixed semidiurnal tides - two high and low tides of unequal size

36. Tides What causes tides?
Summary
What causes tides?
Tides are caused by the gravitational pull of the sun and the moon that cause “bulges” on Earth.
The tide rises when coastline enters the bulge and falls when it rotates out

37. What are the different types of tides?
Summary
What are the different types of tides?
Spring tides occur when the sun and moon are in a straight line
Neap tides occur when the sun and moon form a right angle with Earth

38. Where is the largest tide on Earth found?
Tides
Summary
Where is the largest tide on Earth found?
The Bay of Fundy in Canada is known for its large tidal range (differences of over 50ft have been recorded!)

39. Tides What is the Saltstraumen?
Summary
What is the Saltstraumen?
The Saltstraumen has the strongest tidal current in the world.

40. Exploring the Deep Ocean

41. What do the movies Titanic and Avatar have in common?

42. On March 26, 2012, Cameron reached the bottom of the Mariana Trench, the deepest part of the ocean, in the Deepsea Challenger submersible. He was the first person to do this in a solo descent, and only the third person ever to do so.

43. Cameron dove to a depth of 35 756 feet (6
Cameron dove to a depth of feet (6.77 miles), to the bottom of the Challenger Deep in the Marianas Trench, the deepest spot in the world’s oceans.
It was only the second time in history that man had visited this spot, the first being 53 years ago, in 1960.

44. The Deepsea Challenger

45. The Deepsea Challenger

46. The Deepsea Challenger (Video Snippet)