By: Samantha Zamora
Convection Current Experiment:
- Fill two bottles with warm water from the tap and the other two bottles with cold water. Use food coloring or the Fizzers coloring tablets to color the warm water yellow and the cold water blue. Each bottle must be filled to the brim with water.
- Hot over cold: Place the index card or old playing card over the mouth of one of the warm water bottles. Hold the card in place as you turn the bottle upside down and rest it on top of one of the cold water bottles. The bottles should be positioned so that they are mouth to mouth with the card separating the two liquids. You may want to do this over a sink.
- Carefully slip the card out from in between the two bottles. Make sure that you are holding onto the top bottle when you remove the card. Observe what happens to the colored liquids in the two bottles.
- Cold over hot: Repeat steps 2 and 3, but this time place the bottle of cold water on top of the warm water.
The sun heats the surface of the earth and the layer of air closest to the earth. This warm air rises and mixes with other atmospheric gases. When the sun goes down, the less dense warm air high up in the atmosphere often blankets the colder air that rests closer to the surface of the earth. Because the colder air is more dense than the warm air, the colder air is trapped close to the earth and the atmospheric gases do not mix.