Todor M. Mishonov

An undergraduate laboratory experiment for measuring ε 0, μ 0 and speed of light c with do-it-yourself catastrophe machines: electrostatic and magnetostatic pendula

An experimental set-up for electrostatic measurement of , separate magnetostatic measurement of and determination of the speed of light according to Maxwells theory with percent accuracy is described. No forces are measured with the experimental set-up, therefore there is no need for a scale, and the experiment cost of less than £20 is mainly due to the batteries used. Multiplied 137 times, this experimental set-up was given at the Fourth Open International Experimental Physics Olympiad (EPO4) and a dozen high school students performed successful experiments. The experimental set-up actually contains two different pendula for electric and magnetic measurements. In the magnetic experiment the pendulum is constituted by a magnetic coil attracted to a fixed one. In the electrostatic pendulum when the distance between the plates becomes shorter than a critical value the suspended plate catastrophically sticks to the fixed one, while in the magnetic pendulum the same occurs when the current in the coils becomes greater than a certain critical value. The basic idea of the methodology is to use the loss of stability as a tool for the determination of fundamental constants.An experimental setup for electrostatic measurement of ε0, separated magneto-static measurement of μ0 and determination of the velocity of light c = 1/ √ ε0μ0 according to Maxwell theory with percent accuracy is described. No forces are measured with the experimental setup therefore there is no need of a scale and the experiment price less than £20 is mainly due to the batteries used. Multiplied 137 times, this experimental setup was given at the fourth open international Experimental Physics Olympiad (EPO4) and a dozen high school students did very well. This article, however, focuses on the catastrophe theory, which is the basis of the methodology.

Planck’s constant measurement by Landauer quantization for student laboratories

A simple experimental setup for measuring Plancks constant, using Landauer quantization of the conductance between touching gold wires, is described. It consists of two gold wires with thickness of and length, and an operational amplifier. The setup costs less than

Manhattan equation for the operational amplifier

30 and can be realized in every teaching laboratory in two weeks. The use of an oscilloscope is required.