A blog of Python-related topics and code.

Python Quiz Advent Calendar: explanations

Here are the explanations for the Python Quiz Advent Calender puzzles which appear over December 2020.

Uranium enrichment and the separative work unit (SWU)

Natural uranium consists largely of two isotopes, $\mathrm{^{235}U}$ and $\mathrm{^{238}U}$. The less-abundant (0.72%) isotope, $\mathrm{^{235}U}$ , is important for nuclear reactors and weapons because it is the only isotope existing in nature to any appreciable extent that can sustain a fission chain reaction (that is, it is fissile).

Surface-to-volume ratios of some solid shapes

The shape with the minimum surface-to-volume ratio is the sphere. The code below plots this ratio for a variety of shapes as a function of a characteristic length:

Langton's ant on a hexagonal plane

Langton's ant is a two-dimensional cellular automaton usually implemented on a square grid in which each cell has one of two states (white or black). The ant moves according to the simple rules:

Visualizing vibronic transitions in a diatomic molecule

The Morse oscillator code introduced in a previous blog post can be used to visualize the vibronic transitions in a diatomic molecule by creating two Morse objects (one for each electronic state) and plotting their potential energy curves and energy levels on the same Matplotlib Axes object.