Friday, December 16, 2011

Thinking about Humidity....

Have I said lately how much I love Seeds of Science?  We have been exploring weather in our classroom using this module for weeks now.  One of my favorite investigations is exploring humidity.  We set up five stations with humidity strips to test for humidity in the air.  Humidity is the measure of water vapor and is a major indicator of precipitation and cloud coverage. 

We place strips on the roof of a closed system with water in it... and with out water in the system.  If there is humidity in the air, the strips will turn pink or purple.

Next, we put humidity strips on a tray and wave it with a cardboard fan.  A real fan works better, but I didn't have one available. We also put humidity strips on the closed system of a plastic bag - that the students breathe into.  Yes, water vapor from the!
Our last investigation involves putting strips on a pencil that hangs over a cup of hot water that we have warmed in a kettle.  That was immediate and a lot of fun to see.
The students were able to record their data on a chart to see that they were able to get a positive result for humidity over warm water, in the closed system with water and in the closed system with breath in a bag.  The students them were able to understand why meteorologists measure humidity in order to predict precipitation. 

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