Microscope Resolution Tuesday, December 6, 2016

What it shows:  The wave nature of light limits our ability to see the very small. Application of the Rayleigh limit of resolution tells us that the size of the smallest objects one can resolve under a microscope is approximately equal to the wavelength of light.

Pulse Reflections in a Coax Cable Thursday, February 25, 2016

What it shows:  A voltage pulse, injected into a long coaxial cable, will travel down the length of the cable and undergo a reflection at the other end. The nature of that reflection depends on how the cable is terminated at the other end. Shorting the cable at the far end produces an inverted reflection. With no termination (an "open" end), the reflected pulse is not inverted. When the impedance of the termination matches that of the cable, there is no reflection.

OHP Kinetic Theory Model

Simulation of molecular motion (Brownian, diffusion, etc.) with ball bearings on shaking table.

What it shows:

Two dimensional simulations of molecular dynamics and crystal structure using ball bearings. It can be used to show qualitatively the dynamics of liquids and gases, and illustrate crystalline forms and dislocations.

Bernoulli Wind Tunnel

What it shows

Bernoulli's Principle states that the pressure exerted by a fluid is velocity dependent; the faster the velocity the lower the pressure. This can be demonstrated by a form of Venturi tube, a pipe with a narrow constriction which forces an increase in fluid velocity.

Karate Blow

The instructor breaks several boards with a swift blow of the hand.

What it shows:

The impulse momentum theorem is demonstrated in a most dramatic way by breaking several boards with the blow of your fist. You need not be a karate expert to show how the force of a well executed hammer-fist strike will easily break a stack of five to eight boards. The impulse is given by

impulse = F∆t = ∆mv

The point of the demonstration is: the greater the speed, the smaller ∆t will be and thus the greater the force.