Investigation 7
How are ocean currents created?
Introduction
Points
|330
The ocean is constantly in motion. If you’ve ever been swimming, you may have felt a current that was pulling
you indifferently of the wave action. These large movements of water are currents, and they are responsible for
the mass movement of ocean water around the planet.
Objectives
1. To determine how currents are created
2. To determine how currents interact
3. To determine how water is transported around the planet
Materials
Styrofoam cups
Plastic Containers
Hot Plates
Blue ice
Food dye
Water
Before Class
Go online and review the following video prepared by your teacher:
“Global Patterns of Currents”
Answer the following questions:
1. What creates currents? (5pt)
2. What is upwelling? (5pt)
3. What is the “Global Conveyor Belt”? (5pt)
4. What primarily makes water sink? (5pt)
Procedure Part I
1. To start, you will need the basic apparatus of the tub and stand cups. Fill your tub with water to the bottom
of the hazy section of plastic. Place the tub on the stand cups. You will also need to acquire a specially cut
heat-cup, a pipette, and a small amount of dye. Do not get the dye on your clothes, skin, or any where in the
classroom- it will not come out. Ever.
2. Once there is hot water available in the classroom, acquire some in your heat-cup. Be careful, as it will burn
you.
3. Place a small amount of dye in the bottom of your container, using the pipette to place it on the bottom. If
you are unsure at all, ask or watch the demonstration. Describe what the dye does when placed in the water
below: (10pt)
4. Now, simultaneously place the heat-cup directly under the dye spot (outside and underneath the tub) while
dropping two blue-ice cubes in the opposite end of the tub. If you aren’t sure, ask or watch the demonstration.
5. What is happening to the red dye? (10pt)
6. What is happening to the blue-ice cubes? (10pt)
7. For approximately 10 minutes, you will need to observe the interactions in the tub. Describe those
interactions below: (20pt)
Part II
1. Empty out and refill your tub. This time, you will be placing the spot of dye in the middle of your tub (still
on the bottom). Repeat the experiment in the same manner, but this time, place two ice cubes at BOTH ends of
your tub. Record your explanation of what happens below: (20pt)
2. Empty out and refill the tub again. Now, place two spots of dye at both ends, and place the ice cubes in the
middle of the tub. Explain what happens below: (20pt)
Study Questions
1. Knowing what you know about density, describe the density (relative to the host water) of the red water:
(10pt)
2. Knowing what you know about density, describe the density (relative to the host water) of the blue water:
(10pt)
3. What was the tendency of behavior of cold water? (10pt)
4. What was the tendency of behavior of warm water? (10pt)
5. Describe the interaction that took place when the red (warm) water approached the area that was originally
occupied by the blue (cold) water. (20pt)
6. Describe the interaction that took place when the blue (cold) water approached the area that was originally
occupied by the red (warm) water. (20pt)
7. What is the difference between cold and warm water? (other than temperature) (10pt)
8. Suppose that you went on a world-tour, international floating contest. The first event is in Hawaii, where the
ocean is warm. The second event is in Norway, where the ocean is cold. Which location would you be able to
float in easier? (20pt)
9. Think about the tub. Imagine that representing the world’s ocean. Where would a location be that warm
water would encounter cold surface temperatures, and sink? (10pt)
10. Think about the tub. Imagine that representing the world’s ocean. Where would a location be that cold
water would encounter a warm bottom-heat source, and rise? (10pt)
11. California and northern Florida are at approximately the same latitude. However, the Pacific Ocean in
California is very cold, while the Atlantic Ocean in Florida is very warm. Where might that Pacific Ocean
water be coming from, since it certainly isn’t warm from the sun’s energy? (20pt)
12. Bottom water frequently becomes nutrient rich, since things tend to sink when they die. What does this
mean for locations where this deep-water rises up to the surface? (10pt)
13. The world’s currents are described as a “Global Conveyor Belt”. Meaning that water can be pushed all
around the world, driven by density differences created by temperature and salinity. Look it up online, and
draw in the “Global Conveyor Belt” below. Use red to indicate warm waters, and blue to indicate cold waters.
Use a solid line to indicate bottom waters, and use a dotted line to indicate surface waters. (60pt)