Derivation of the brachistochrone curve using variational calculus. Discussing its tautochrone property.

With the least-action-principle and Lagrangian mechanics to Newtonian mechanics.

What is going on with the glowing gherkin? Introducing a highly simplified model to explain, while the gherkin glows only on one end.

Calculating the shape of a jet of tap water.

Why the minima of a slit's interference pattern are seen under the same angle as with an obstacle of same width.

Calculating the horizon distance when looking from a certain altitude.

An analytical solution of the Navier-Stokes equations for a highly simplified flow problem