The water in the ocean is constantly moving thanks to two different types of currents – surface and deep.

Surface currents are due to the winds that affect the given area and usually affect the top of the ocean. These currents generally push water towards land and are responsible for the waves we see on the beach.

Deep currents are due to the sinking action of cold water that comes from the poles, which then drifts to the equator, warms up, and rises to the surface again and drifts towards the poles where it cools off, creating a cycle of rising and sinking water throughout the ocean. Deep water currents are also affected by the salinity, or how salty, of the water.

In this science demonstration, your kids will see the effects of deepwater convection currents. Let's begin!

Ocean Currents

Materials Needed

You will need the following:

• Clear bowl
• 2 cups
• Eyedropper
• Warm and cold water
• Blue food coloring
• Salt

Steps to Complete

Here are the steps to follow to simulate deep water currents in a glass:

1. Fill one of the cups with half a cup of cold water.  Add a teaspoon of salt and several drops of food coloring. Fill the other cup with half a cup of warm water and add a teaspoon of salt plus several drops of food coloring. Mix both cups well. 
2. In the bowl, mix one cup of cold water with one tablespoon of salt and mix well. Now, use the eyedropper to slowly add some of the warm blue water and observe what happens. Once you are done your observations, pour the water out.
3. In the bowl, mix one cup of warm water with one tablespoon of salt and mix well. Now, use the eyedropper to slowly add some of the cold blue water and observe what happens. Once you are done your observations, pour the water out.

Results

You should see that the warm colored water rose to the top as it mixed with the cold water. You see that the cold colored water sank to the bottom as it mixed with the warm water.

Explanation

The currents you are observing here are convection currents, which are found in the deep waters of the ocean. Cold water sinks and hot water rises creating movement, or currents, in the ocean.

Additional Resources

Looking for some easy-to-use science plans that will teach your students about the oceans? Here is what we offer:

• Lapbooking through Planet Earth
• The Sassafras Science Adventures Volume 4: Earth Science 

You can also see more activities to learn about the ocean at our Beach Science Pinterest board: