the knowledge

The Thought Emporium's update on the home-brewed gene therapy he took to cure his lactose intolerance. It reports how the effect held up over two years and what future versions might look like.

CGP Grey argues for picking a theme for the year or season instead of setting goals or new year's resolutions. He explains how a theme gives direction without a pass/fail target.

PBS Space Time explains Noether's theorem: conservation laws such as energy and momentum are consequences of deeper symmetries. It also covers why those laws hold only under certain conditions.

An animated 11-minute tour of the whole field of mathematics as a single map, showing how pure and applied math and their sub-fields relate to each other.

MinutePhysics, with 3Blue1Brown, explains Bell's theorem using a Venn diagram paradox and polarizing filters. It shows why no local hidden variable theory can reproduce quantum correlations.

Veritasium asks people where a tree's mass comes from, then explains that most of a dry tree's mass originates from carbon dioxide in the air. It combines street interviews with a short explanation of photosynthesis.

A 20-minute S3 episode touring Terraform Industries, a startup making synthetic natural gas from air and solar power. It walks through the reactor, injection system, direct air capture and electrolyzer, plus the company's cost goals and next milestone.

CGP Grey explains how the 2015 UK general election showed the flaws of first-past-the-post voting, with parties like UKIP winning many votes but few seats.

PBS Space Time, together with It's Okay to be Smart and PBS Eons, asks how a universe drifting toward disorder produced something as complex as life. It presents the idea that the laws of physics, through thermodynamics, may actually favor the emergence of life.

Adam Neely analyzes vaporwave through music theory, timbre and nostalgia, and includes a parody track made for the video. He also touches on the phenomenology of music.

Kurzgesagt explains the skyhook, a rotating cable with a counterweight that could catapult spacecraft from Earth orbit toward deep space. It covers why it would make space travel cheaper and more efficient.

A short CGP Grey explainer on why 'Holland' is wrong as a name for the whole country of the Netherlands. It covers the country's provinces and its constituent territories.

A School of Life video arguing that everyone marries someone who is somewhat wrong for them, and that this is unavoidable. It is a four-minute version of an essay by Alain de Botton.

Historia Civilis explains the constitution of ancient Athens, including its assembly, offices and use of sortition to choose leaders. It draws on Aristotle and Plutarch.

ScienceClic gives a 15-minute animated introduction to quantum field theory, covering fields, spin, conserved quantities, the standard model and interactions.

Applied Science explains how retail anti-theft tags work. A tiny magnetostrictive strip acts as a mechanical oscillator excited by a magnetic field, and magnetizing or demagnetizing it arms or disarms the tag.

Munro Live's Model Y episode 36 has Sandy Munro walk through the disassembled Tesla Octovalve and heat pump system. He explains how the components are made and what each one does.

Short Curious Droid video on why NASA could not simply rebuild the Saturn V's Rocketdyne F-1 engine for the SLS boosters. It explains that the engines were hand-tailored and that much of the know-how was never documented, so the blueprints were not enough.

Not Just Bikes introduces the "stroad", a street-road hybrid common in the US and Canada that fails at both jobs. He contrasts it with Dutch design, where each road has a single purpose, and covers cost, danger and ugliness.

A short BicycleDutch video on how the Netherlands got its cycling infrastructure, including the 1970s protests and the shift away from car-centric planning. The channel later published an updated version.

3Blue1Brown walks through a very hard Putnam competition problem and its elegant solution, emphasizing the visual intuition and the thought process behind solving it.

Not Just Bikes argues that the Netherlands, famed for cycling, is also the best country for drivers. It explains how prioritizing walking, cycling and transit makes driving faster and more pleasant.

A short CGP Grey explainer on the alternative vote (instant runoff voting) versus first past the post, made around the 2011 UK referendum. It shows how ranked ballots are tallied and why they avoid spoiler effects.

Robert Miles explains the orthogonality thesis: how an agent can be highly intelligent while pursuing goals that seem stupid or alien to humans. He separates intelligence from goals and touches on the stamp-collector example.

An 11-minute animated introduction to P vs. NP and the wider landscape of complexity classes, inspired by the Complexity Zoo wiki. It assumes no background in computer science.

Bill Hammack of engineerguy explains how medieval engineers designed stone cathedrals using rules of thumb, with no science, mathematics or literacy. He uses it to define the engineering method.

Vox Earworm explains why John Coltrane's Giant Steps is so hard to improvise over: it is fast and moves through three keys. Musicians Braxton Cook and Adam Neely walk the host through the underlying music theory.

A short clip from Carl Sagan's Cosmos in which he explains how Eratosthenes measured the circumference of the Earth using shadows in two Egyptian cities. It is a clear, visual account of an ancient scientific feat.

Not Just Bikes argues that people in walkable, bikeable Dutch cities stay healthy because exercise is built into daily life, which he calls the gym of life. It contrasts this with car-dependent cities that require deliberate workouts.

Not Just Bikes explains why cars rarely crash into buildings in the Netherlands, attributing it to street design that forgives mistakes and to systematic crash investigation. It contrasts this with North American acceptance of such crashes.

An animated Kurzgesagt explainer on bacteriophages, viruses that kill bacteria, covering how they infect and burst cells and their potential as therapy against antibiotic-resistant bacteria.

Not Just Bikes shows how traffic calming is built into streets across the Netherlands, from city centres to villages. Street design naturally slows cars and makes roads safer.

A PBS Space Time episode introducing de Broglie-Bohm pilot wave theory, an interpretation of quantum mechanics that avoids much of the strangeness of the mainstream views. It is aimed at curious lay viewers.

CGP Grey, adapting The Dictator's Handbook, explains how rulers keep power and why succession causes trouble when they die. It is the sequel to his video on the rules for rulers.

Looking Glass Universe explains de Broglie-Bohm pilot wave theory (Bohmian mechanics) as an alternative to the standard interpretation of quantum mechanics. The video lays out the pros and cons of the theory and links to related videos on contextuality and entanglement.

PBS Space Time explains the Higgs field and how the Higgs mechanism gives particles mass within quantum field theory. It is a ten-minute overview for a lay audience.

A PBS Space Time episode explaining the holographic principle: the idea that our 3+1 dimensional universe may be described by information on a lower-dimensional boundary. It walks through black hole entropy and the AdS/CFT correspondence.

3Blue1Brown presents Bayes' theorem through a geometric diagram, showing how evidence should update beliefs. It works through the Kahneman and Tversky style questions and base rates.

Not Just Bikes explains the Dutch concept of autoluw, or nearly car-free, streets and how it is applied across the Netherlands, with examples from Toronto and Copenhagen. It also covers Amsterdam's move toward a nearly car-free city.

An Economics Explained video arguing that the Netherlands shows taxes alone can't reduce wealth inequality. It distinguishes income inequality from wealth inequality and discusses the Gini index.