contract tests

3Blue1Brown explains why positive results on accurate medical tests are often false positives, and reframes Bayes' rule using likelihood ratios (Bayes factors) to update odds. It uses visual examples to make the reasoning intuitive.

Scott Manley explains the Cold War experiments in which steel and aluminium spheres, known as Lew Allen's Balls, were placed near nuclear detonations. The spheres survived the fireball, and he walks through what the declassified results show.

Veritasium explains magnetism as a consequence of special relativity. Length contraction of moving charges makes a current in a wire attract or repel a nearby moving charge.

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.

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.

A Medlife Crisis video by cardiologist Rohin Francis on overdiagnosis and over-screening. It explains how detecting more disease does not necessarily mean saving more lives, and covers harms such as unnecessary treatment.

3Blue1Brown builds toy SIR models to simulate how an epidemic spreads and tests scenarios like social distancing, travel restrictions, central gathering places and quarantine. It was made during the early COVID-19 outbreak.

Technology Connections explains why electric kettles are uncommon in the US, centering on 120V circuits limiting power. He tests ways of boiling water on gas, electric ranges and kettles.

Guitarist Jim Lill methodically tests what in an electric guitar affects its tone, swapping parts on a partscaster and even trying a 2x4 body. He finds that wood and construction matter far less than people assume.

America's Test Kitchen tests eight carbon-steel skillets to find the best one, asking whether a single pan can replace stainless, cast iron and nonstick. It names a winner and covers how the pans perform.

Adam Neely tests the claims for tuning to A=432 Hz by trying the unusual tuning systems that its proponents' numerology requires. He compares how they sound against standard tuning and temperaments.

A Vox Borders episode with Johnny Harris explaining how China is gradually erasing the line between mainland China and Hong Kong since the 1997 handover. It describes the one country, two systems arrangement and its expiration date.

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.

Matthias Wandel tests old and new code on a range of PCs, including a new mini PC, to measure how much faster modern hardware really is. He also shows optimization techniques such as branchless code, with benchmark programs on GitHub.

Isaac Arthur examines the Dark Forest theory, Cixin Liu's proposed solution to the Fermi Paradox in which civilizations stay silent and may destroy any that reveal themselves. He tests the theory's underlying assumptions and arguments.

Aging Wheels tests how towing trailers affects the range of electric trucks, including a Silverado EV. It shows that trailer aerodynamics matters far more than added weight.

Veritasium examines research suggesting science explainer videos like Khan Academy's make students feel they understand while tests show they have not learned, because misconceptions go unaddressed. It suggests how to partly fix this.

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.

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.

The Thought Emporium follows up on his earlier video showing negative ion products are radioactive, reporting that Amazon pulled listings and companies shut down. He tests more radioactive quack products with a Geiger counter and cloud chamber.

James Hoffmann runs caffeine analyzer tests comparing filter versus espresso, extraction over time, steep time, instant coffee and light versus dark roast.

Geekerwan's Chinese-language review of Intel's Lunar Lake lightweight laptop chip, covering performance, perf-per-watt curves and battery life benchmarks. It tests whether x86 can compete on efficiency.

Oh The Urbanity! tests the theory that banning housing investors would fix affordability, using Rotterdam's ban as a case study. The video finds mixed results.

The Thought Emporium tests so-called negative ion and anti-5G wellness products and finds they are radioactive, with some coated in powdered thorium.

Technology Connections tests how quickly gas, induction and standard electric stoves boil water, with CO2 measurements and a discussion of the advantages and disadvantages of each.