Presentations

Hertz Resonator

What it shows:

The transmission and detection of radio frequency electromagnetic radiation by use of LC oscillator circuits recreates the discovery by Hertz of a method to generate and detect electromagnetic waves.

Optical Analog of Uncertainty Principle

What it shows:

In the Heisenberg uncertainty relation, the momentum of a particle cannot be known with any greater accuracy than h/∆x where h is Planck's constant and ∆x is the uncertainty in spatial position. The more you localize its spatial position, the less certain you become about its momentum. An optical illustration for this is the diffraction of light though a slit.

Hot and Cold Gas in Balloons

A balloon is dropped in boiling water, and another balloon is cooled with liquid nitrogen to demonstrate the effect of temperature on volume of gas in a balloon.

A 4 liter beaker on a hot plate, with a liter of water boiling within. A prepared balloon, filled with air and tied so that it just fits in the beaker, is dropped into the beaker. The balloon expands to seal the beaker and is forced up by the vapor pressure, ending up on top of the beaker, too large to fit inside.

NMR model

What it shows:  Using the classical description of the motion of a spin in an external magnetic field, the demonstration helps visualize NMR in the time domain. The nuclear magnet and its classical vector model are represented by a spinning ball with magnets attached. A rotating mass is characterized by its angular momentum L, which is the analog of the magnetic moment mu, which characterizes a rotating charge distribution. The spinning ball mimics protons in that it has both angular momentum as well as an "intrinsic" magnetic moment.

Jaw Models

Cardboard animal jaws as examples of levers.

What it shows:

The biting force of an animal depends upon the magnitude, direction and point of application of forces exerted by the jaw muscles. A mammalian jaw exerts a greater force than does a reptilian jaw despite a more delicate joint structure, because evolution has improved the physics of eating.

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