1. Ocean Currents
Chapter 16.1

2. Ocean Currents
Masses of ocean water that flow from one place to another.

3. Currents
Two types of ocean currents:
Surface currents
Deep currents

4. Surface Currents
Currents that ONLY move horizontally in the UPPER part of the Oceans surface
Develop from friction between the ocean and the wind that blows across the surface.

5. Color your surface current map using the Key on your Surface Current Map! BLUE = Cold Current RED = Warm Current

6. Global Winds Create Currents Draw and Label a Global Winds Diagram according to this diagram.

7. Gyres
Huge circular-moving current systems that are driven by the global winds.
5 main gyres!

8. Locate the 5 main Gyres on your surface current map
Locate the 5 main Gyres on your surface current map. Label the Gyres on your map

9. The Coriolis Effect Video Explanation
The deflection of the currents from their original course because of the Earth’s rotation.
Just like a merry go round!

10. Because the Earth Spins
Currents are deflected:
To the Right in the Northern Hemisphere
To the Left in the Southern Hemisphere

11. Why?
Great Britain and Alaska are at similar latitudes, yet Great Britain is about 25 degrees warmer than Alaska…

12. Ocean Currents and Climate
Gulf Stream is a great example of bringing warmth to a high latitude.
It brings heat from the equator region to areas more North and South

13. Deep Currents VERTICAL (up and down) currents of ocean water
Caused by differences in
water density
Dense water SINKS
LESS dense water RISES

14. Deep Currents A result of temperature or salinity changes temp = sinks
density

15. Color in your Global Conveyer Belt Map Cold = Blue Warm = Red

16. Tides
Chapter 16.2

17. What is a Tide?
The rise and fall of the sea level.

18. The gravitational pull of the Moon and the Sun make the tides

19. Sun Vs. Moon
The Sun is much larger than the Moon but has ONLY about ½ of the power of the Moon on tides
WHY?
Because the Moon is Closer

21. Spring Tides
The Sun, Moon and Earth are in a straight line.

22. Spring Tides Come once every two weeks.
During a full and new moon phase

23. Spring Tides
Highest High Tides and Lowest Low Tides
Why?

24. Spring Tide
Gravitational Force!!

25. Neap Tides
When the Sun Moon and Earth are at right angles.

26. Neap Tides Happens about twice a month
Happens at the 1st and 3rd quarter Moon Phase

27. Neap Tides
Tidal Range is the smallest. (NOT MUCH DIFFERENCE between high tide and low tide!)
Lowest High Tides and Highest Low Tides
Why?

28. Neap Tide Forces
Gravitational and Centrifugal
Centrifugal

29. Spring Tide vs. Neap Tide
Spring Tide Force is all in
one direction
Neap Tide Force is from two directions at the same time

31. Tide Animation

32. One Tidal Cycle = 24 hours & 50 minutes
There are usually two high tides and two low tides each day.

33. Why the extra 50 minutes?
As the Earth is rotating and revolving the Moon is revolving as well. It takes an extra 50 minutes for the Earth to catch up with the Moon.

34. Tidal Cycles – 3 types

35. Diurnal Tidal Cycle One high tide and one low tide per tidal cycle.
Uncommon

36. Semidiurnal Tidal Cycle
2 identical high tides and two identical low tides per tidal cycle

37. Mixed Semidiurnal Tidal Cycle
2 High and 2 Low tides – all of different heights.