59 posts on physics. All posts · RSS feed
The Klein–Nishina formula gives the differential cross section for the scattering of photons off an electron. At low energies, light scatters elastically (Thomson scattering); at higher energies (for example, gamma radiation), inelastic Compton scattering occurs. In terms of the incoming and outgoing photon wavelengths, and …
An atomic nucleus consists of protons and neutrons (collectively referred to as nucleons) bound together through the strong nuclear force. Models for the nuclear binding energy were introduced in a couple of previous posts on this blog. The semi-emprical mass formula (SEMF), also known as …
Inspired by this recent Numberphile video, here is a demonstration of chaos in a simple dynamical system: two balls, with near-identical starting conditions, bounce around elastically off a circular wall. After a short time, the balls' trajectories diverge completely. SciPy's solve_ivp can be used to …
A quick update on this blog article with some extra cross sections and an additional plot of Maxwell-averaged reactivities. The processes covered are: The cross section gives a probability for the reaction to occur as a function of the collision energy. In practice, the colliding …
In his 1986 book, Surely You're Joking, Mr. Feynman! physicist Richard Feynman writes: We have learned a lot from experience about how to handle some of the ways we fool ourselves. One example: Millikan measured the charge on an electron by an experiment with falling …
Icebergs in adverts stand tall on a narrow point, but a real one would tip over onto its side. This short Python script models a two-dimensional iceberg under its weight and buoyancy, animates the forces as it rolls into its stable orientation, and explains why …
This previous post introduced a simple molecular dynamics simulation for the equilibration of the speeds of the particles of an ideal gas. The present post extends the code a little to model the effusion of an ideal gas through a small hole into a vacuum.
Just a quick update on this blog post on visualizing the electric field of a multipole arrangement of electric charges to visualize the electric field of a capacitor (two oppositely-charged plates, separated by a distance ). The code, which uses Matplotlib's streamplot function to visualize …
A previous blog post provides a class, ColourSystem, which can be used to predict the colour (within some colour system) of a provided spectrum. This post uses the class to determine how to combine a number of light emitting diodes (LEDs), or other light sources …
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 …
