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Al Tobias (wat4y) - Office: Rm. 201, (434) 924-0538 - Lab: Rm. 202, (434) 924-6800

Physics Demo Manual

Demonstrations are cataloged according to PIRA Bibliography


Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.

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 Motion In One Dimension
 Motion In Two Dimensions
 Newton's First Law
 Newton's Second Law
  video  - The Atwood Machine
  video  - Helium Balloon Accelerometer
 Float Accelerometer
 Newton's Third Law
 Statics Of Rigid Bodies
 Applications Of Newton's Laws
 Work and Energy
 Rotational Motion
 Properties of Matter

 video  - Helium Balloon Accelerometer


Archimedean inertial force can be illustrated (with a Helium and Argon filled balloon) in an accelerated fluid of uniform density (air in a glass box - aquarium).


The first video below has an upside-down aquarium tank with an ORANGE Helium-gas filled balloon. The second video below has two balloons, the ORANGE balloon filled with Helium-gas and the BLUE balloon filled with Argon-gas.

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When spinning the container in a circular path (i.e.. person holds cart and spins with their legs being the axis of rotation), lighter-than-fluid objects move toward the axis of rotation along the centripetal acceleration vector, while heavier-than-fluid objects move away from the axis of rotation. This is the basis of the explanation for the behavior of a helium filled balloon in a car, which moves in the direction of the car's acceleration.

References: Meiners 8-3.2 & 8-3.9, Graetzer & Williams, Am. J. Phys., 31, 302 (1963)