Fun with Frederick & Fleming – Feeling Air Pressure

This experiment might bring you back to your school days as this is an experiment that is often done in science class to demonstrate air pressure.

Air is pressing down around us with a pressure of about 15 pounds per square inch. That air pressure is about equivalent to an elephant on an end table. Our bodies are built to withstand this pressure and since we are used to it, we don’t feel it. BUT there is a way to get a slight feeling of that which Amy got to experience.

This is an experiment that should only be done with adult supervision to insure safety. We had Amy step into a 100 gallon garbage bag. Of course NEVER put a plastic bag over anyone’s head. Before we do anything, the air pressure on the outside of the bag is equal to the air pressure inside the bag. By making a relatively tight seal around Amy and using the vacuum to suck the air out of the bag, the air pressure on the outside of the bag is now greater than the pressure inside the bag. This will apply a force that Amy will be able to feel. To make this work, Amy had to cup her hand over the vacuum nozzle to keep it from sucking in the bag or clothing.

Amy didn’t feel the full impact of the 15 lbs of pressure per square inch because we didn’t have a perfectly air tight seal. BUT the pressure was pushing down so hard, movement was next to impossible until we let the air back in the bag and the pressure equalized again.

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