lock testing

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.

Practical Engineering explains how canal locks work, including the water-saving basins of the new Panama Canal locks.

Destin of Smarter Every Day goes behind the scenes at the 23andMe lab to show how genotyping works. He also discusses DNA testing and privacy.

3Blue1Brown explains the math and mechanics behind Bitcoin visually: ledgers, digital signatures, proof of work and the blockchain, building up a decentralized payment system from first principles.

A Technology Connections video essay on how analog and digital clocks shape different mental models of time, with the minute hand acting as a progress indicator.

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 Vox video on Barcelona's superblocks, an urban design approach that closes interior streets to through traffic to return space to pedestrians.

Veritasium explains why the one-way speed of light has never been measured, only the round-trip speed, since measuring it requires synchronized clocks that assume the answer. It explores the implications for relativity.

Tom Scott investigates the claim that the microwave was invented to heat hamsters, and interviews James Lovelock about freezing and microwave-thawing hamsters in the 1950s. It traces early magnetron uses beyond radar.

Benn Jordan explains how Flock Safety's license plate cameras log and share vehicle locations, and explores how adversarial AI can defeat them. It covers weak security and the surveillance risks of private police-camera networks.

A five-minute CGP Grey explainer arguing that a phone is effectively an extension of your mind, and that any backdoor or master key into encrypted devices will inevitably be abused or leaked. It frames the encryption debate as locks that are either unbreakable or absent.

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.

A doctor from Medlife Crisis explains in under three minutes why even a rich patient should not simply order every medical test, touching on pre-test probability and Bayesian reasoning. False positives make blanket testing counterproductive.

An MTA video on communications-based train control, the system meant to replace the New York City subway's century-old signaling. It also shows the mechanical interlocks and signals in use today.

Sabine Hossenfelder explains how special relativity leads to the block universe, in which past, present and future all exist equally, and asks what that means for whether the past still exists.

Tom Scott explains the famous Dutch flower auction clock at Royal FloraHolland in Aalsmeer, a literal Dutch auction, and how the internet changed it. It is a short look at how the system worked then and now.

Tom Scott explains why electronic voting is a bad idea. Elections must be trusted by everyone and attacks on software scale in ways attacks on paper do not, so open source or blockchain fixes do not solve it.

CGP Grey argues that your brain treats a whole home as one room during lockdown, blurring work, rest and leisure. He recommends creating separate spaces and routines for different activities to stay balanced.

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.

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.

Historia Civilis traces the history of work and time discipline, comparing modern working hours with those of medieval peasants and the changes brought by clocks and industrialization. It draws on works such as Schor's The Overworked American.

Adam Savage shows a set of Mitutoyo ceramic gauge blocks and uses them to explain metrology, the science of measurement. He argues that accuracy and precision work differently than most people assume, which changes how you think about every measuring tool.

Marques Brownlee explains why iMessage's blue and green bubbles matter, covering the technical, commercial and social side of Apple's messaging lock-in. It also discusses RCS and what could be done about it.

Veritasium's Derek Muller spends an hour in a silent, dark anechoic chamber at BYU to test the claim that 45 minutes is the most anyone can bear. He reports on his experience and other people's reactions.

GoldenSound publishes music on Tidal to test MQA, a deep dive into the format's claims and problems including its leaky filter. Testing begins around the 5:45 mark.

Scott Manley tells the story of a computerized telemetry system built to sit at the heart of a nuclear test device in place of the plutonium pit, designed to transmit data in the microseconds before it was destroyed.

A scene from The Big Short in which Jared Vennett pitches credit default swaps on mortgage bonds to a hedge fund team, using a Jenga tower to illustrate collateralized debt obligations.

WIRED has UCLA professor Amit Sahai explain zero-knowledge proofs to a child, a teen, a college student, a grad student and an expert. Each round goes deeper into the cryptography and why it matters.

A two-minute clip of Andreas Antonopoulos explaining why a 51% attack on Bitcoin would not destroy it and what such an attack would cost. It is a succinct take on mining security.

Numberphile with Tadashi Tokieda on the Trinity Hall Prime, a prime number whose digits form a picture of the college's coat of arms, left as a gift by a departing mathematician.

Oh The Urbanity! argues that most city dwellers live in dense residential neighbourhoods outside downtown, which can be calm and peaceful. It draws on older, denser parts of Toronto and Montreal.

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.

A short video from the trafficwaves.org site showing how traffic jams and standing waves form, including the fight between cheaters and blockers at an exit-lane backup. It also touches on how individual driving behavior affects the flow.

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.

Veritasium explains why bicycles are stable, arguing that gyroscopic effects are not the answer. The video shows countersteering and an experiment where riders blocked from steering the opposite way cannot turn.

Mark Rober digs into bed bugs, testing popular beliefs about where they come from and how to get rid of them. It mixes entertaining experiments with research-based advice on what works and what does not.

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.

Geoff Cumming uses a simulation to show how wildly the p value varies from one replication to the next because of sampling variability. He argues for estimation and confidence intervals over null hypothesis significance testing.

Tom Scott visits Penistone to explain the Scunthorpe problem, showing why naive web and profanity filters block innocent words.