lock testing

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

An 8-minute explainer on the Lightning Network and how it relates to Segwit, Bitcoin and Litecoin. It covers how off-chain payment channels route payments to scale blockchain transactions.

Matt Cutts of Google explains what cloaking is: serving different content to search engine crawlers than to users. He covers why it violates Google's webmaster guidelines.