Ocean Currents

Experiment Title:

How do ocean currents cause change in the ocean?

Objective:

Learn about Ocean currents and how they change through the year and what they do to change the ocean

Background on Ocean Currents:

An ocean current is movement of ocean waters that changes with the seasons. These currents can be driven by changes in temperature, wind, salinity differences (how salty the water is), breaking waves (when the waves hit a land mass), the Coriolis Effect (movement of the water due to the rotation of the earth), and cabbeling (when water molecules join together and form a molecule that is more dense than the water molecules alone, causing the water molecules to sink in the water and create a current, this tends to happen with changes in temperature and salinity).

The picture below shows the common ocean currents around the globe, many ocean currents travel horizontally around the globe and curve vertically when they interact with various land masses.

Ocean currents flow for great distances, and together, create the global conveyor belt which plays a dominant role in determining the climate of many of the Earth’s regions. More specifically, ocean currents influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any other region at the same latitude. Another example is Lima, Peru, where the climate is cooler, being sub-tropical, than the tropical latitudes in which the area is located, due to the effect of the Humboldt Current.

Materials

• Plastic Cups
• Water
• Oil
• Shaving cream
• Food coloring
• Salt

Method

Prepare Experiment

      1) Station 1: Salinity of water – slowly add salt to a small cup and see if increasing the salinity  

          (saltiness of water) to see if you can make different objects float

• Start with a cup of water
• Add your test object into the water. Does it Float or Sink?
• Now add a teaspoon (tsp.) of salt and mix it into the water
• Test your test object again. Does it sink or float?
• Repeat two more times?

          The ocean based on the temperature of the water or if fresh water is flowing into the area can 

          areas of different salinities. Different levels of saltiness can allow things to float or sink, it is 

          the same with water, water that is more salty will typically sink leaving less salty water near  

          the surface. This effect can create currents with sinking and rising waters. This effect also 

          creates things like super salty lakes on the ocean floor.

               

      2) Station 2: Volcanic Gases in water – adding alka-seltzer to water can mimic volcanic gases 

          released from active volcanic jets under the water (normally you would have a temperature 

          different causing currents to mix the gases in the water, but here it will be accomplished by 

          stirring the water as the alka-seltzer dissolves.

• Start with a cup of water
• Drop an alka-sletzer tablet into the water
• Gently stir the water with a stir stick
• What happens to the bubbles? Do they continue to just go straight up or do they distribute through the water?

          Normally temperature differences in the volcanic jets and the surrounding ocean creates 

          currents that help to mix the volcanic gases with the water. This distributes nutrients and helps 

          to make the oceans very nutrient rich throughout various areas instead of just small areas 

          having a lot of nutrients.

      3) Station 3: Currents and Shipping – Ocean currents can greatly reduce the time it takes a ship 

          materials across the sea, but when things go wrong the current can lead to disastrous outcomes.

• Start with a glass of water
• Use the squirt bottle to add a drop of water
• Mix your water, what happens to the drop of oil?
• Now add a bit more oil and mix?
• What happens to the oil now?

          What you should see is a small oil leak because the oil and water do not mix is not such a 

          difficult thing to deal with, but a lot of oil over a current can spread and break into many 

          different areas that then all have to be cleaned. Oil tankers have spilled all over the world , 

          luckily many of the spills have been contained to limit their spread in the ocean.

     4) Station 4: Rain and the ocean – using water and shaving cream create your own rain system

• Start with a glass of water
• To the top add a bit of  shaving cream, enough to not see the top of the water
• Now add a few drops of food coloring and watch what happens.

          The ocean as it circulates evaporates massive amounts of water into the atmosphere, this 

          creates different high and low pressure systems throughout the world and thus creates the 

          amazing weather that we experience every day, from super-hot and dry to cold and wet.

               

      5) Station 5: Viscosity in the ocean – salt water can become clogged with other materials such as 

          sea slime that can slow and change ocean currents.

• Start with a glass of water and use a straw to blow bubbles and mix the water
• Does the water mix easily? (you may add a drop of food coloring to be able to see how it mixes a bit easier)
• Is it difficult to blow bubbles in the water?
• Now get a glass of bubble solution and blow bubbles in it and mix it
• Does it mix easily? (you may add a drop of food coloring to be able to see how it mixes a bit easier)

          Plant and other debris can form ocean slime. This slime is much thicker (more viscous) than 

          water and can make it hard for animals to move while in the ocean. It can also make it much 

          harder for the currents to move materials through the ocean. Certain slimes can grow very  

          large and cause the current to shift direction, leading to changes in the weather and the flow of 

          the overall world.

Conclusions

Ocean Currents have a vital function in our planet. Without them our weather would not exist as it does today, massive areas of the ocean would be barren because they had no nutrients, and life may not have developed.

Make It Your Own

What ideas can you come up with to test differences in the ocean currents?

Extension Activities to do at home

Try dissolving different materials into water, how do those materials affect all of the different experiments we did today? What if instead of water you use oil in all the experiments? Do things change when the entire body of fluid is high viscous?