good explanations

Technology Connections praises a 1940s-50s Sunbeam toaster and explains what makes a toaster well designed, drawing on a vintage Sunbeam video.

A Healthcare Triage episode summarizing the evidence on the health benefits of exercise, made in response to people misreading the host's column on exercise and weight. It argues exercise offers large benefits.

CGP Grey explains the Single Transferable Vote, a proportional ranked-ballot system, and why politicians have little incentive to adopt it. It is a short animated explainer of how multi-winner ranked voting works.

A Wendover Productions explainer on how China built the world's largest high-speed rail network so quickly and why its rail strategy differs from America's. It covers politics, social benefits and the economics of unprofitable lines.

Not Just Bikes compares the same cycling trip to a hardware store in Calgary and in Amsterdam, using a 'plus 1 minus 2' format. It shows how street design shapes how safe and practical cycling is.

CGP Grey's short explainer arguing that caffeine addiction is mostly harmless and may even be beneficial. It covers what caffeine does in the body.

Techmoan's beginner introduction to the compact cassette, testing metal tapes and Dolby S noise reduction on a Sony TC-S1 deck. He checks whether a cassette can sound close to a CD when good tape and equipment are used.

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.

Not Just Bikes takes on the common excuse that a country is simply too big or spread out for good transit and walkable cities. The video argues that city density and short everyday trips matter, not national size or overall population density.

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

A four-minute 2006 explainer on trusted computing, describing what it is and whether users should support it, with a skeptical DRM angle.

Bill Hammack of Engineer Guy explains the engineering behind the aluminum beverage can: why it is cylindrical, how it is manufactured, why it narrows at the top, the double seam, and how the pull tab works.

Veritasium explains quantum entanglement and spooky action at a distance, walking through Bell's inequality and the experiments that rule out hidden variables, in under ten minutes.

The first of four short videos from Bill Hammack (engineerguy) introducing and giving the history of a 100-year-old mechanical computer, Michelson's harmonic analyzer. The series goes on to explain Fourier synthesis, analysis and operation of the machine.

3Blue1Brown builds visual intuition for quaternions, showing how to think about this four-dimensional number system using stereographic projection and rotations in 3D space. It is part one of a two-part series with an interactive companion site.

Huygens Optics explains the Fourier transform and shows how a lens performs one optically. A DLP projector is used as a Fourier filter to do simple pattern recognition on lithographic character patterns.

An animated visualization of basic quantum mechanics using a free particle, with simulations based on the actual equations. It covers waves, particles, and how measurement collapses the wavefunction.

Mick West explains the three Navy UFO videos (FLIR, GIMBAL and GOFAST) released in 2020, giving mundane explanations such as a distant plane and camera artifacts. He notes the videos were not new and had been circulating since 2017.

3Blue1Brown visualizes the Riemann zeta function and the analytic continuation that extends it beyond where its series converges, building toward the Riemann hypothesis.

3Blue1Brown visualizes Feynman's lecture on the refractive index, explaining why light appears to slow down in glass and why the effect depends on color. It builds the idea from waves produced by oscillating charges in the material.

Game Maker's Toolkit examines Nintendo's design approach of starting from a core play mechanic, making it fun, and building around it. Examples include Mario's jump and Luigi's Mansion's vacuum.

CuriousMarc powers up a vintage HP 5061A cesium beam clock and explains both the quantum principle and the HP implementation in detail. It is part of a longer atomic clock series.

A short Al Jazeera animation narrated by Amy Goodman presenting Noam Chomsky's five filters of the mass media: ownership, advertising, media elite sourcing, flak and a common enemy. It is part of the MediaTheorised series.

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.

Smarter Every Day shares a binaural audio recording of the SpaceX Falcon Heavy launch made by Trevor Mahlmann, with explanations of the sounds including the sonic booms of the landing boosters. It is meant to be heard with headphones.

Astrophysicist David Kipping presents the halo drive, a proposed way to propel a starship to a good fraction of light speed by gaining energy from a black hole. The video is based on his peer-reviewed paper and explains why energy is the main obstacle to interstellar flight.

Veritasium tells how Kodak film was fogged by radioactive fallout from the first atomic tests, letting the company detect nuclear testing before anyone announced it. The video also covers the deal to keep it quiet and how fallout contaminated packaging.

Fermilab's Don Lincoln explains why light travels slower in water and glass. He knocks down common wrong explanations such as absorption and re-emission, then gives the wave-mechanics reason tied to refractive index.

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.

Destin of Smarter Every Day films a cat falling in high-speed slow motion to show how cats right themselves in midair, and introduces the physics behind it.

Dr Mike Pound of Computerphile shows how a modern laptop can crack Enigma, using a ciphertext-only attack based on an older paper. He compares it with the tooling in CrypTool.

Kraut traces centuries of political development, from Mongol rule and the Orthodox church to Muscovite autocracy, that shaped Russia's authoritarian state. It uses countryball animation and compares Russia with Europe and China.

Veritasium takes an IQ test and examines what IQ measures, its history including military use and eugenics, its controversies, and how it correlates with life outcomes. Experts including Cecil Reynolds and Stuart Ritchie contribute.

Kurzgesagt's animated explainer on the human immune system, describing the body as an ecosystem and how immune defenses cope with the variety of invaders. It promotes their book Immune.

Technology Connections explains the early history of analog color television, from the 1954 start of modern color broadcasting, and how shadow masks work in CRTs. It is the first in a series on how analog color TV works.

Veritasium explains in detail how LIGO detects gravitational waves, with a laser interferometer measuring displacements smaller than a proton. The video focuses on the extreme precision and the techniques needed rather than the general discovery story.

A Veritasium video that follows the principle of least action from Bernoulli and Newton to quantum mechanics, asking whether light takes all possible paths at once. It includes experiments showing quantum waves.

Tom Scott explains how in Norway and other Nordic countries tax returns, and so individual incomes, are public. He looks at the effects of wage transparency and whether it is a good idea, with sources listed in the description.

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.