Physics Capsule is the best place to learn physics online and for free. There are several resources out there full of details about physics, but few cater to readers with various backgrounds in physics, and fewer still are self-contained. Have we not all, perhaps even once too often, gone link-hunting to understand a chain of ideas only to forget where we began?

This website was founded by two teachers and researchers of physics to fill in the gaps with two aims: one, to make a resource that can help anyone understand physics, so long as they put in some minimal effort; and two, to cover as much ground as possible while keeping the compendium largely self-contained so people can focus on learning without being overwhelmed.

Two things closely linked to physicists and academia inspired the design of Physics Capsule: books and $ \LaTeX\ $. This website is laid out like what a book would be if it grew on the web (read more in our editorial) and it is typeset in Palatino eText, reminiscent of our love of $ \LaTeX $.

Palatino eText is based on Palatino Linotype designed in 1950 by the German type designer Hermann Zapf and punchcut in metal by August Rosenberger of D. Stempel AG. One of the authors (VHB) had admired this type since he first saw it in Frankfurt am Main; when introduced to it the other (RS) too enjoyed the type and it was decided that we would go big on Palatino on this website.

It was also decided, however, to use the slightly modified eText version, also by Hermann Zapf, along with Toshi Omagari, in 2013, improved for screens. Since Physics Capsule is primarily for screen-based consumption this has always felt to us like an excellent choice ever since we started.

Coded from scratch in Mysore, India, Physics Capsule runs on powerful Solid State Drive servers in Los Angeles, California, and is served from one of 118 Cloudflare edge caches around the world. For our formulae we use – and support – MathJax, the cross-browser mathematics rendering engine supported by the likes of AMS, Pearson, APS, Springer and PLOS.

Articles are almost entirely typed in $ \TeX\ $ and mathematics is typeset in $ \TeX\ $ Gyre Pagella created by the GUST Font Source Library based on Hermann Zapf's URW Palladio which was itself based on Mr Zapf’s older design Palatino. This close link between the text and maths typefaces we use is why reading Physics Capsule is such a pleasure.

‘I do not want to label myself a crystallographer as against a physicist and think indeed that though my research is concerned with crystals it is the physical side of it which attracts me.’
— Lawrence Bragg