You may have tried the can crushing pressure demo, you may have even tried it with a 55 gallon drum, but have you tried an entire tanker car? In the December CoolStuff Newsletter, Bridgette Sparks of Saline High School in Michigan talks about the high pressure environment she has created in her classroom! Well, at least with the subject matter!
I, too, start my gas unit by having the class participate in a discovery based lab exercise very similar to the "Gas Laws Smorgasboard" mentioned in a previous Cool Stuff newsletter. Towards the end of class, I start playing David Bowie's Under Pressure or Billy Joel's Pressure since most of the lab stations are explained using pressure differences. When the students enter the classroom the next day we discuss pressure differences by observing the can crusher demo as a whole class. This time I use a larger paint thinner can and have the class explain using scientific principles. This is followed up with the next two questions and videos:
The air pressure is significant but could we do the same thing with a 50 gallon drum?
Or, how about a tanker car?
The Magdeburg hemispheres are another cool example of how atmospheric pressure can have a significant effect on Earth. Invented by German scientist and mayor of Maddeburg, Otto Von Guericke in 1656 to demonstrate the concept of atmospheric pressure. By sealing a pair of large copper hemispheres with grease and the air pumped out, the sphere contained a vacuum and could not be pulled apart by a team of thirty horses until the valve was opened to release the vacuum.
The force holding the hemispheres together is equal to ~9000 lbs, equivalent to lifting a car.
Re-enactments of Von Guericke's 1656 experiment are performed in locations around the world by the Otto von Guericke Society. The experiment has also been commemorated on two German stamps.
After learning about Guericke's pump, Scientist Robert Boyle, working with Robert Hooke in designing and building an improved air pump. From this, they formulated what is called Boyle's Law, which states that the volume of a body of an ideal gas is inversely proportional to its pressure.
A very big thank you to our contributors for this article:
Saline High School
Dwight "Buzz" Putnam,
Whitesboro High School