Name:____________________________________________
Block:__________
Deep Ocean Currents Lab
Background: A surface current is an ocean current that generally flows in the upper 1000
meters of the ocean and is primarily driven by the wind. A density current flows at the bottom
of the ocean and can circulate in the deep ocean for 500-2000 years before resurfacing. A
density current is heavier and denser than surrounding water; such dense water masses sink.
Density currents move very slowly compared to surface currents. They can be found in all of
the world’s oceans and connect with global surface currents to form a complete path of
circulation. This is known as the Global Conveyor Belt.
The densest water in the oceans
comes from polar regions, due to
the intense cooling and freezing
that occur there. When seawater
freezes, most of the salt is left
behind. As salinity increases, the
density of the seawater also
increases. Evaporation can also
cause the salinity to increase. The
water evaporates and leaves
behind the salt, therefore
increasing the salinity of the water
that remains.
Procedure:
1. Fill plastic container about half full of cool tap water.
2. Place a thermometer in the container and wait 2 minutes. Record in Celsius.
3. Take the spoon and retrieve a colored ice cube. Place the ice cube in the plastic container.
4. Observe what happens to the cold water from the ice and draw a diagram.
5. After two minutes of observing/drawing record the temperature of the water.
6. Retrieve hot water that has been colored and gently pour the water down the inside edge of the
glass. Don’t disturb the rest of the water.
7. Observe what happens to the hot water and draw a diagram.
8. After two minutes of observing/drawing, record the temperature of the water.
Data/Analysis:
Cool Tap Water Temp.
Ice Water Temp.
Hot Water Temp.
1. What happened after adding the ice cube? Describe in words and draw a picture of the
container including the colored ice/cold water.
2.
What happened after adding the warm water? Describe in words and draw a picture of the
container.
Conclusion Questions:
1. Was the colored water moving away from the ice cube colder or warmer than the water in the
glass?
2. Was the warm colored water that was added colder or warmer than the water in the glass?
3. Where would the floating ice be found in the ocean?
4. Where would cold water be found? Near the pole or near the equator?
5. Where would cold water flow in the ocean? Near the surface or near the ocean floor? Explain.
6. Where would the warmest waters be found? Near the pole or near the equator?
7. Where would warm water flow in the ocean? Near the surface or near the ocean floor? Explain.
8. Which direction would cold water move in the ocean? Toward the pole or toward the equator?
9. Which direction would warm water move in the ocean? Toward the pole or toward the equator?
10. Scientists have found that water in the ocean is well mixed. How do differences in temperatures
mix ocean waters?
11. Predict what would happen if we used water with a higher salinity. How would the salty water
flow? Explain your reasoning.
12. If higher salinity water is found in areas with either freezing temperatures or evaporation,
where would you expect to find water with higher salinity?