Module 1 August 30, 2012

Class Challenge

Quiz 1.Identify all the Oceans 2.Identify all the Continents 3.Label where main the Mid-Ocean Ridges are. 4.Label where the Ocean Trenches are.

The Motion of the Ocean The strongest motion in the ocean is at its surface and is made up of surface currents and waves. Ocean surface currents are in regions where winds regularly blow over the ocean in a reasonable constant direction and velocity, pushing the water along. Surface currents, then, are large, horizontal movements of water molecules being pushed by the winds above them.

The winds in our atmosphere result from temperature differences caused by heat from the sun. The heat is the strongest at the equator, and weakest at the North and South poles.

To understand wind patterns, consider cold air near the surface of the earth at the North Pole. The air will move from the North Pole toward the equator, to even out the temperature differences. As it makes its way there, however, it encounters warmer climates. This warms up the air, causing it to rise.

When the air makes it to the 60 degree N latitude, it becomes so warm that it rises into the upper atmosphere and begins moving back toward the North Pole. This sets up a loop of winds that travel continuously from the Pole to a latitude of about 60 degrees North and back again.

Now look at the equator. We see the exact opposite effect. As the warm air rises, it starts traveling back to the poles. At a latitude of about 30 degrees North, it cools down enough to sink and begin traveling back toward the equator. From the equator there is also a loop of winds that travel to a latitude of about 30 degrees North and then turn around and come back again.

In the middle of these two loops of wind (between 30 degrees and 60 degrees) there is a third loop that occurs as a reaction to these two loops. These winds are represented in brown in Figure 1.14 on page 21.

Coriolis Effect The winds moving toward the equator curve in a direction opposite of the rotation of the earth. The way in which the rotation of the earth bends the path of winds and resulting sea currents

Because of the Coriolis effect, these winds bend west (opposite the rotation of the earth) and approach the equator at a 45 degree angle. These winds Are called Trade Winds.

Westerlies Farther away from the equator the winds near the surface of the earth (between 30 degrees and 60 degrees) are bent opposite the Trade Winds because they are traveling away from the equator instead of toward it. The Coriolis efffect causes them to bend in the opposite way. These winds are called Westerlies.

Polar Easterlies The northernmost and southernmost winds are called the polar easterlies and re the most variable winds of all. They curve in the same direction as the Trade Winds, since they once again move toward the equator near the surface of the earth.

Currents

Now all these major wind fields in the atmosphere push against the ocean surface and create currents. All the major currents of the open ocean are driven by the wind. As the wind moves across the water it forces the surface currents to move at a 45 degree angle from the wind direction.

Gyres Large, mostly circular systems of surface currents driven by the wind. As water gets “pushed around” all over the world, large surface currents result in a circular pattern.

Tides Sarasota, Sarasota Bay, Florida 29 August August ° N, ° W :56 EDT 1.52 feet High Tide :09 EDT Moonset :45 EDT 1.23 feet Low Tide :08 EDT Sunrise :32 EDT 2.32 feet High Tide :30 EDT Moonrise :11 EDT 0.26 feet Low Tide :53 EDT Sunset :52 EDT 1.53 feet High Tide :09 EDT Moonset :35 EDT 1.04 feet Low Tide :08 EDT Sunrise :25 EDT 2.29 feet High Tide :09 EDT Moonrise :46 EDT 0.39 feet Low Tide :52 EDT Sunset

Vertical Motion of the Thermoclines: Experiment 1.A Supplies: Fish Tank filled with water Pitcher of Cold water Food dye Introduction: To observe the upturning of the water when colder water is introduced to the tank.

Proceedure: 1.Fill tank with cold water ¾ full. 2.Add food dye to warm water. 3.Observe the water movement. Observations: Conclusion:

Homework Class Challenge Study for Quiz on Currents Read Module 1 Pages 20 – 28 Answer OYO Questions: 1.10 – 1.15 Answer Study Guide Questions: define j – o and 10 – 17 Complete Lab Book Take Module 1 Test