Convection Current Demonstration

Friday, November 9, 2018


Convection currents are the result of uneven heating of water or air. These currents create some of our wind, weather, and ocean currents.
In order to demonstrate convection currents, I first froze blue water into ice cubes. I next used red food coloring to create red water and then heated this water. When I place these objects in the water you can see how the different temperatures of water flow.
The hot water flows upward and the cold blue water flows downward. This flow is due to density difference caused by the difference in temperature. Cold water is denser than warm water.

Materials for this convection current demonstration
Red and blue food coloring
Ice cube tray
Bottle for the hot water
Fish tank or any large clear container

Why do convection currents occur?
Cold water is denser than warm water. As water cools the molecules become packed together more tightly which results in more mass per volume.  Objects that have a greater density than another object will always settle below the less dense object. For example, oil is less dense than water, therefore water will always settle below oil if the two liquids are poured into a container.
The convection current occurs as the water of different densities moves in order to fall above or below objects of different densities. The warm less dense water moves upward because it is less dense than the cold more dense water that moves downward. This resetting of the water creates currents.

Events created by convection currents.

Local winds many times are caused by convection currents. The land heats up and cools down more rapidly than a body of water like the ocean. This difference in temperature creates convection currents which produce sea breezes and land breezes.

Ocean currents are also caused by convection currents. Many of the currents created by convection currents occur below the surface or even deep in the ocean.

Severe weather As a large body of cold air moves into an area of warm air the warm air moves upward quickly and this creates a low-pressure system which may create severe storms.

Convection currents of molten rock in the earth may result in volcanoes and earthquakes.

The movement of tectonic plates occurs because on convection currents.

Additional Videos on Convection Currents

Convection currents crash course
This video revies how convection currents cause ocean currents and wind.

Convection
This video by Teachers Pet reviews how convection currents are created.



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