The Laws of Physics

tamiby: Tami O’Connor

My husband and I just returned from his reunion at Cornell University.  He attended the law school, so, while he reminisced with his friends about this loophole and that exception, I became curious about other events being held at the university.  I scanned the various offerings, and though he was interested in the course entitled “Effective Strategies for Conducting Online Legal Research”, the class entitled “Favorite Physics Demonstrations” at 2:00 PM jumped off the page at me.  The immutable laws of physics were just the diversion I needed! I made my way to the Physics building, arriving early.  I found plenty of hands-on materials placed all around the lecture hall for the spectators to “play” with.  To my delight, I had a “reunion” of my own with many products from Educational InnovationsSinging Rod! Air ZookaTornado TubesSound Tubes!  A Hand-Cranked generator!  And more…  All my old friends were here! The presenter’s table was covered with classic physics demonstration items: a Van de Graaff generator, bicycle wheels, magnets, and a host of other items. He had sound devices, and a table covered with glasses filled to varying levels with water.  From the 30’ ceiling hung a cable with a ball weighing about 10 pounds.  Fog leaked from a container of liquid nitrogen, and a large wooden box stood nearby.  I just knew it would be a fun afternoon!

Laws of Physics

What do paint and perfume have in common?  Using Bernoulli’s principle, the presenter, Dr. Philip Krasicky demonstrated how, when air flows faster, its pressure decreases.  Using two wide-diameter McDonalds’ straws, he stuck one in a glass of water.  With the other, he blew across the open end of the first straw.  With the resulting low air pressure, water rose in the straw and sprayed, via the stream of air, onto the front row spectators.  He explained that devices like paint sprayers and perfume atomizers employ this principle to spray their products.  Clearly, these were some laws we could rely on!

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The Science of Sound Waves

Michelle Bertkeby:  Michelle Bertke

Sound can be a difficult concept to portray because the sound waves cannot be seen or touched.  Luckily, there are several at home experiments that demonstrate the properties of sound waves.

Water tank to show ‘Sound Waves’

Sound WavesYou can use a fish tank half filled with water to give a visual demonstration of ‘sound waves’.  Water is a perfect medium to show the propagation of waves. This demonstrates how sound waves travel though the air.  There are two ways to display this activity.  One way is to simply press your hands onto the top of the water and allow the waves to be made by the pressure of your hand.  This allows students to see how waves travel though a medium.  You can also use this to point out the aspects of a wave such as frequency and amplitude.  Another way to show waves is to place a speaker next to the tank and allow the sound to produce the waves.  This can show that sound is a form of pressure just like your hand. Read the rest of this entry »