nation state

Scott Manley explains rotating detonation engines, how they differ from pulsed detonation engines, and why thermodynamics predicts they beat traditional jet and rocket engines.

Veritasium explains how investigators caught the Golden State Killer using forensic genealogy, matching crime scene DNA to distant relatives in public genealogy databases. It also covers the privacy implications of DNA databases.

Ben Felix rebuts common arguments for holding only US stocks, such as past outperformance and international revenue exposure. He supports the case for international diversification with cited academic research.

Tom Scott visits the US National Helium Reserve in Amarillo, Texas, and explains why headlines that the world is running out of helium are misleading. He covers the Federal Helium Program and its planned privatization.

National Geographic footage showing the cordyceps fungus infecting ants and other insects and steering their behavior so it can reproduce.

CGP Grey explains what it means that a third of the United States is federally owned land. It describes the agencies that manage it and why so much of it is in the western states.

2swap explains how he solved the Klotski sliding-block puzzle by mapping its full state space as a graph and visualizing it. The video includes footage of the Guinness world-record solve and links to an interactive graph.

CGP Grey explains that postal codes are routing instructions for mail rather than geographic regions. He looks at the quirks and problems this causes.

A minutephysics video explaining why a piano cannot be perfectly tuned, comparing equal temperament with just intonation and the math of harmonics.

WonderWhy surveys complex international borders, including enclaves like Vatican City, San Marino and Lesotho, the enclave-within-enclave town of Baarle, and the India-Bangladesh Cooch Behar region.

A short CGP Grey explainer about how countries are defined, why recognition by others matters, and the oddities of places like Taiwan and Vatican City. It shows that statehood is partly a matter of diplomacy rather than fact.

12tone tells the story of pitch inflation and how concert A came to be standardized at 440 Hz, including attempts at legal standards. It is a short music history explainer.

Technology Connections takes apart the step-by-step electromechanical logic of a 1970s pinball machine. He shows how relays, steppers and switches track state and score without electronics.

Tom Scott follows the ISO 3103 / BS 6008 standard to make an international standard cup of tea, using specialist tasting equipment. The video shows how precisely the standard is specified.

CGP Grey explains the history of the US Social Security card and number, and why they became a de facto national ID despite never being meant for it. He also covers why America resists a proper identity card.

A short How to ADHD explainer, featuring Brendan Mahan, on why simple tasks can feel impossible for people with ADHD. It introduces the 'wall of awful', a pile of past failures, shame and anxiety that builds up in front of a task and blocks starting it.

Digital Foundry's Alex Battaglia analyzes Metro Exodus Enhanced Edition, the first AAA game built around ray tracing. It covers the new global illumination, emissive lighting, DLSS and performance on AMD and Nvidia hardware.

PolyMatter examines how universities, especially in the West, depend on foreign and Chinese student tuition and how rankings and incentives distort institutions around that money.

James Hoffmann explains how decaf coffee is made, how the decaffeination processes differ, and why decaf is roasted and stales differently. He also discusses decaf quality and health questions.

Anders Puck Nielsen clears up common misunderstandings about what legally counts as genocide, then compares the situation in Gaza with the genocide case against Putin. The chapters cover the definition, individual intent, and the two case comparisons.

Dr. K of HealthyGamerGG explains why people feel unmotivated and unable to start tasks after hours of YouTube or similar distractions. He frames it as a result of how social media is designed to capture attention, and says not to blame yourself.

A Vox Borders explainer on Hong Kong's housing crisis, the least affordable market in the world, and the tiny cage homes and subdivided flats people squeeze into. It looks at why prices keep climbing and how land policy contributes.

Stated Clearly explains the RNA world hypothesis, which resolves the chicken-or-egg problem of genes versus enzymes by proposing that RNA once did both jobs. It outlines how evolution could begin with RNA chains alone.

CGP Grey explains why European diseases devastated the Americas while few deadly diseases traveled the other way. He ties it to livestock domestication, dense cities, and the ideas of Guns, Germs and Steel.

A video explaining why Japanese cities look the way they do, through Japan's national tiered zoning system that permits mixed use and flexible development. It compares this approach with more restrictive zoning elsewhere.

An illustrated 23-minute summary of David Friedman's talk based on The Machinery of Freedom. It describes how law, police and courts could work as market services in a stateless society, covering private law, polycentric law and objections.

Ben Felix explains how to compare renting and buying a home by looking at unrecoverable costs, and distills it into the 5% rule of thumb. It is framed for a Canadian audience but broadly applicable.

A clip from the 1983 BBC series Fun to Imagine in which Richard Feynman explains heat as the jiggling of atoms and how we perceive it as hot and cold.

Ben Eater gives a detailed look at how an NPN bipolar junction transistor works and what it does. It is an eleven-minute explanation aimed at building real understanding of the device.

Veritasium tells the story of the Fast Fourier Transform, from its use in detecting nuclear tests to Cold War politics, and how it could have changed the arms race. It includes a short, intuitive explanation of what the Fourier transform does.

A Blender-animated explanation of the Toyota Hybrid Synergy Drive, showing how the engine, two motor-generators, planetary gearset and battery work together as an eCVT.

Zack Freedman gives advice on why makers fail to finish projects, including scrapping bad ideas, showing work publicly and writing a plan that keeps projects fun. It is aimed at hardware DIY but generalizes.

A mini-documentary by a Canadian living in Japan explaining how an average family can afford a new detached house in Tokyo. It covers how houses are treated as depreciating assets and how Japanese zoning and building practices keep prices low.

Veritasium explores why time seems to speed up as we age, covering chronoception and several competing explanations beyond the common proportional-theory argument.

PolyMatter explains China's housing bubble and why around 50 million homes sit empty. It covers cultural and economic reasons behind the overbuilding and the government's bind.

Joseph Everett compares the food environment of the US, with roughly 30% obesity, to Japan's, around 3.5%. He argues that what is available and normal to eat explains much of the gap.

Thunderf00t presents high-speed camera footage of alkali metals such as sodium and NaK reacting with water. The footage shows that the explosion is not caused by hydrogen ignition, as the usual explanation says. It is a Coulomb explosion driven by electrons leaving the metal.

Lindybeige gives an hour-long history of English coinage and the problems of maintaining a trustworthy currency. It ends with an explanation of why the pounds, shillings and pence system worked so well.

John Green explains why the US spends far more on health care than other countries, going through insurers, drug companies, hospitals and lawyers. He argues the causes are complicated rather than a simple blame game.

A speedrunner-made explanation of the Super Mario World credits warp, an arbitrary code execution glitch that jumps the game straight to the ending. It simplifies the underlying assembly and memory behavior with animations so non-experts can follow.