Name _____________________________________              Date ________

Period _____

 

Ocean Currents!

 

A current is a flow of water moving in the ocean.  Currents flow in all parts of the Earth’s oceans.  A current may be a surface current, deep current or even shoreline current.  Using section 15.2 (pages 345-349) in your science book you are going to look more into each of these types of currents and find out how they all work together to keep the ocean an active place.

 

Surface Currents

  1. What is the Coriolis Effect? 
    1. Apparent force that bends the earth’s winds and ocean currents

 

  1. What causes the Coriolis Effect?
    1. Earth’s eastward rotation

 

  1. Use your knowledge of the Coriolis effect to answer this question:  imagine you are sending a rocket to the Moon.  If you were to launch the rocket to the Moon would you want to aim your rocket at the Moon’s present location and then launch?  Why or why not?

You would want to aim your rocket ahead of the moon since the Earth is moving and the Moon is moving.  You will need to send it on a curved path or it will miss the Moon.

 

  1. Draw a picture of your rocket on the Earth’s surface, the moon in the sky, and draw a line indicating your launch path to the Moon.

 

Surface Currents and Wind Patterns

  1. In what direction do the northeast tradewinds blow?
    1. SW

 

  1. In what direction do the westerlies flow?
    1. NE

 

  1. In what direction do southeast tradewinds flow?
    1. NW

 

  1. What causes the prevailing winds to curve?
    1. The rotation of the Earth in an easterly direction

 

  1. How does the wind direction effect the surface currents on the Earth?
    1. If the winds change direction, the surface currents change direction.  The winds effect the surface currents movement.

 

Surface Currents in the World Ocean

  1. Look at figure 15.9.  What do you notice about the types of currents that flow from the equator and the types of currents that flow from the poles?
    1. Equator:  Warm currents
    2. Poles:  Cold currents

 

  1. What is a gyre?  Explain how they flow different in the N.H. and the S.H.
    1. A gyre is when the surface currents form in circular patters
    2. In NH: clockwise and in SH: counterclockwise

 

  1. Which current influences the water off the coast of Florida?
    1. The Gulf Stream

 

Deep Currents

  1. Why do you think deep currents are also called density currents?
    1. Colder water has a higher density than warm water, so it sinks.  The cold, dense water forms deep currents.

 

  1. In which direction do deep ocean currents tend to flow?
    1. Northward or southward

 

  1. What is an area of upwelling?
    1. Upwelling is when cold deep water moves upward to take the place of surface water.  As this happens it brings up all the nutrients from the ocean floor.

 

  1. Predict why you might find a lot of fishing ships located near an area of upwelling.
    1. Where there is upwellings the water is rich with nutrients and ocean life.

 

Shoreline Currents

  1. What is the difference between shoreline currents and surface and deep currents?
    1. Shoreline currents travel short distances; surface currents and deep currents travel thousands of kilometers

 

  1. What shoreline currents form where waves approach the shore at an angle?
    1. Longshore currents

 

  1. What shoreline currents form when water carried to the shore pulls back toward the ocean?
    1. undertows

 

  1. What shoreline currents are narrow, powerful streams of water that flow at a right angle to the shore?
    1. Rip currents

 

  1. How can a person escape a rip current?  Why?
    1. Swim parallel to the shore; the rip current is narrow and perpendicular to the shore

 

  1. What happens if a swimmer tries to swim toward the shore while caught in a rip current?
    1. The person will make little progress and soon become tired because the current is very strong