What it shows

When two different size soap bubbles are connected together, the smaller diameter bubble will shrink and collapse to blow up the larger diameter bubble. One can use this to demonstrate Laplace's law or the phenomenon of minimizing the surface area of a soap film.

How it works

Laplace's law tells us that the gauge pressure of a spherical membrane is given by 2γ/r, where γ is the surface tension and r is the radius of the sphere.¹ For soap bubbles (which have an inside as well as outside surface), the gauge pressure is twice...

What it shows:

The growth and decay of current in an RL circuit with a time constant visible in real time.

How it works:

By choosing the values of resistance and inductance, a time constant can be selected with a value in seconds. The time constant τ is given by

τ = ^L/_R

We chose two resistance values, 4.7K and 10K coupled with a 45kH UNILAB ¹ induction coil giving time constants of 9.5sec and 4.5sec respectively.

The circuit is set out on a 1.0 × 0.5m plywood board. The actual...

What it shows:

A device to measure distances to an accuracy of fractions of the wavelength of light, it also provided the critical experiment for the non-existence of the ether and for the constancy of the speed of light in all inertial frames.

...

Smoke cell under microscope; smoke particles seen bombarded by air molecules.

What it Shows

Brownian motion shows direct evidence of the incessant motion of matter due to thermal energy. Here we use the random bombardment of smoke particles by air molecules.

How it Works

The CENCO Brownian Movement Apparatus consists of a metal chamber with a glass viewing window on top and a lens on one side (see figure 1). Smoke from a piece of smoldering rope or match is drawn into the chamber through an inlet tube by squeezing the rubber bulb....