Thursday, May 20, 2010

Air Pressure experiment

We did an experiment about air pressure. First we took a couple of plastic soda bottles and put balloons over the top of them.
Our first experiment involved warming up the air molecules. We did this by running the bottle under some hot water.
Miraculously, the balloon started to inflate. You can't really tell by the picture but it visibly got bigger. This told us that the molecules started to vibrate and bump into each other, increasing the space around each molecule. Each molecule was using more space for motion, the air expanded and became less dense (lighter). The same number of air molecules occupied a larger space or the same sized space with increasing the air pressure.
We put a second bottle in the freezer for a couple of minutes to cool the air molecules down. Those little air molecules huddled together and moved more slowly thus taking up less room . The amount of space the air took up shrunk, or reduced the air pressure. You can't beat science experiments!!

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