tenth man

Numberphile with Dr Holly Krieger shows how the digits of pi surprisingly emerge from the Mandelbrot set. A short, accessible math explainer.

Practical Engineering compares modern concrete with that of the Roman Empire, covering modern techniques like roller compacted concrete and water-reducing admixtures. It explains the tradeoffs of Roman construction versus reinforced concrete.

CityNerd Ray Delahanty explains induced demand and what happens when freeways are widened. He walks through the economics of supply and demand applied to traffic and asks how much new traffic appears and whether congestion returns.

Kurzgesagt's animated overview of human origins and the vast prehistory before recorded history. It covers how modern humans emerged and spread.

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

Historia Civilis tells the story of 46 BCE, the 445-day year in which Julius Caesar reformed the Roman calendar. It covers the political context, including the civil war, Cato and Cicero.

Kaze Emanuar explains how he rewrote and optimized the Super Mario 64 source code so it runs far faster on real N64 hardware. He covers performance bottlenecks and fixes in detail for his ROM hacks.

Scott Manley surveys the research on whether people can adapt to rotating artificial gravity, from early Soviet centrifuge tests to modern studies. He concludes it is an engineering problem and discusses Coriolis effects and station radius.

A short explainer on the history and mechanics of public key cryptography and the Diffie-Hellman key exchange. It uses a mixing-paint-colors analogy to show how two parties can agree on a shared secret in public.

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.

Explains induced demand beyond roads, showing that it applies to transit, walking and cycling infrastructure too but with different consequences. It corrects common misunderstandings of the concept.

Part 1 of Smarter Every Day's three-part series on manipulating the YouTube algorithm. It features Renee DiResta and examples of how social media platforms can be manipulated.

A two-minute clip in which Milton Friedman uses a humble pencil to show how thousands of strangers across many countries cooperate, without central direction, to make a simple product. It is a short visual version of the 'I, Pencil' essay's argument about free markets and dispersed knowledge.

Destin Sandlin of Smarter Every Day investigates manipulation on Facebook, interviewing the company's team about content moderation. It is the third video in his series on social media manipulation.

A short clip from the 1983 BBC series Fun to Imagine in which Richard Feynman explains how a train stays on the track. He covers the geometry of tapered wheels that steer the train back toward the center of the rails.

A short CGP Grey bonus video explaining the shortest-splitline algorithm, which draws electoral districts by repeatedly splitting a state along its shortest dividing line while balancing population. It is offered as a neutral, algorithmic fix for gerrymandering.

Mathologer examines how identities like 1+2+3+... = -1/12 arise in Ramanujan's work, starting from his 1913 letter to Hardy. The video explains the rules for summing infinite series and why such results are meaningful but not naive sums.

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.

A PBS clip in which Richard Feynman explains the strange nature of light and electromagnetic radiation. He conveys how little of it we actually see and how radio waves are present everywhere.

Mathologer shows how times table diagrams on a circle produce cardioids and other curves connected to the Mandelbrot set. He explains the patterns and links to a tool for making your own diagrams.

Kurzgesagt explains the Holocene or Human Era calendar, which adds 10,000 years to the current year to anchor dates to the start of human civilization. It argues this gives a more sensible frame for human history.

Richard Feynman, in a clip from the BBC series Fun to Imagine, takes on the puzzle of why mirrors seem to swap left and right but not top and bottom.

AlphaPhoenix uses Monte Carlo simulation and annealing-style methods to draw North Carolina congressional district maps, both gerrymandered and fair. He focuses on the fascinating computational problem rather than the politics.

A short Art of the Problem clip explaining Diffie-Hellman key exchange, using a paint mixing analogy for one-way functions and touching on modular arithmetic and discrete logarithms.

Branch Education walks through a semiconductor fab and the dozens of steps used to turn silicon wafers into microchips, with 3D animation. It covers lithography, deposition and etching at a high level.

Vox's Joe Posner, with help from 99% Invisible, explains why bad doors are everywhere. It covers Don Norman's long-running complaint about doors and the idea that good design should not need instructions.

Yosh trains a reinforcement learning agent to drive Trackmania until he can no longer beat it. The video explains how the training works and the design choices involved.

A Kurzgesagt animation on longtermism, arguing that because the future could hold trillions of people, our actions' effect on future generations may be what matters most.

Tom Scott explains how decades of deep coal mining sank parts of Germany's Ruhr Valley and changed its drainage. Pumps run by Emschergenossenschaft must now work permanently to keep towns and cities from flooding.

Insider explains how The Mandalorian replaced green screens with LED walls that project real-time 3D environments behind actors, with over half the show filmed on such virtual sets.

A short video explaining the Intel Management Engine, a hidden embedded computer inside Intel machines with deep access to hardware. It is presented from an insider's perspective and raises backdoor and NSA concerns.

Vsauce asks how many holes a human has and uses topology to show the answer depends on what counts as a hole, with animations and expert input.

Curious Droid asks what traces human civilization would leave in the geological record 65 million years from now. It considers how thin the fossil record of humanity might be.

Practical Engineering explains how engineers and agencies put a dollar value on a human life to weigh cost against safety. It covers the legal and regulatory basis for these calculations.

Louis Rossmann gives a basic, non-technical introduction to right to repair legislation for people new to the issue.

Scott Manley covers how GPS works and how civilian accuracy went from a planned 100 meters to about one meter. He explains the technology and the removal of restrictions that made this possible.

Scott Manley looks at SpinLaunch, which aims to throw launch vehicles out of a spinning launcher at hypersonic speed. He covers its recent Mach 1 test of a one-third scale launcher and the engineering problems that remain.

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.

Scott Manley examines why SpaceX, Google and others are looking at orbital data centers. He walks through the economics, heat rejection and solar power arguments, with links to the Lumen/Starcloud and Google Suncatcher papers.

Scott Manley explains the thermal balance of spacecraft and how a satellite could be configured to radiate away the heat from datacenter-scale computing in space. His rough numbers suggest it is feasible.