Montessori Upper Elementary: Easy Demonstration of Deep Ocean Currents

Here's an Easy, Cheap Demonstration of Deep Ocean Currents

Our 4th grader, "Peel," is studying the oceans in earth science these days, and I like the simple demonstrations her book recommends (it's Harcourt Science).  To better understand deep ocean currents--the ones caused by differences in water density and differences in water temperature--we did this simple activity:

1.  Freeze an ice cube with food coloring in it the night before you start.

2.  Fill a clear bowl with warm tap water.

As in our Float/Sink works for the Primary Classroom, we used these food prep containers from Sam's Club.

We let the water sit still for 10 minutes before carefully lowering our colored ice cube.

3.  We observed what was happening every 2 minutes, for a total of 10 minutes.

Peel drew pictures of each stage in her science journal.

We began to see a thin blue line of colder, denser water that was sinking.

 4.  Connect what you saw with what you know from reading.

The blue water pooled on the bottom, while the warmer water was displaced.

This demonstration shows that cold water is denser than warm water, so cold water sinks.  This helps explain deep ocean currents.  Salinity, which affects density, also plays a role (but that's for another day!).  There are several good short videos you can link with this activity:

National Geographic
National Oceanic and Atmospheric Administration
Watch. Know. Learn.

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