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Steve Mould shows that LEDs and solar panels are both diodes made from semiconductors, so a solar panel can emit light and an LED can generate electricity. He demonstrates a small solar panel lighting up.

Technology Connections explains how LED traffic lights, which do not melt snow, drew complaints and were blamed for accidents. He uses it to illustrate the 'but sometimes' fallacy against new technology.

A Technology Connections video weighing LED streetlights against high pressure sodium lamps, covering efficiency, color, cost and light pollution. It is a follow-up to his earlier explanation of why street lights are orange.

CGP Grey explains why European diseases devastated the Americas while few deadly diseases traveled the other way. He ties it to livestock domestication, dense cities, and the ideas of Guns, Germs and Steel.

Part one of Technology Connections' account of the VHS versus Betamax format war. It argues Sony was caught off guard by JVC's cheaper, more practical VHS system.

Chubbyemu narrates the true case of a professor who spilled two drops of dimethylmercury on her hand and suffered fatal neurological damage.

A short Veritasium video explaining regression to the mean and how ignoring it leads to wrong conclusions about punishment versus reward, medical treatments and sports streaks. It uses the example of flight instructors who believed criticism works better than praise.

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.

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 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.

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.

A short BicycleDutch episode showing how people with disabilities use Dutch cycle tracks on hand-cycles, tricycles and mobility scooters.

Short Curious Droid video on why NASA could not simply rebuild the Saturn V's Rocketdyne F-1 engine for the SLS boosters. It explains that the engines were hand-tailored and that much of the know-how was never documented, so the blueprints were not enough.

Technology Connections explains how RGB light and color work, from hue and saturation to color vision and how objects appear under different lighting. It uses a studio setup with colored lights to demonstrate the effects.

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.

Tom Scott explains for Computerphile why electronic voting is a bad idea, arguing that paper ballots are transparent, auditable and hard to tamper with at scale. He covers why moving voting to phones, tablets or computers undermines trust and verifiability.

Numberphile interviews cryptographer Ron Rivest about end-to-end verifiable voting. He explains how homomorphic encryption and receipts let a voter confirm their ballot was counted without being able to prove how they voted to anyone else.

Numberphile's Dr James Grime explains the flaw in the Enigma machine, namely that a letter could never be encrypted to itself, and how that helped the Allies break the code. It touches on the Bombe and Alan Turing.

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.

3Blue1Brown illustrates how enormous the 256-bit search space is, showing how infeasible it is to find a hash or key by guessing and checking.

MinutePhysics explains Shor's algorithm, showing how a quantum computer factors large integers by finding the period of a number modulo N. It walks through the modular arithmetic and number theory that give the exponential speedup over classical factoring, and why this threatens encryption.

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.

PBS Infinite Series explains how Shor's algorithm lets a quantum computer break RSA encryption, building on earlier episodes about cryptography and the math of quantum computers. It works through the idea step by step.

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.

Computerphile interview with Prof. Ross Anderson on how Chip and PIN payment systems are being compromised, and the attacks researchers have seen.

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.

A two-minute animated introduction to Bitcoin from 2011, explaining it as a peer-to-peer digital currency. It was widely shared in Bitcoin's early days as the standard newcomer explainer.

Andreas Antonopoulos answers a question about how to secure your Bitcoin. He covers holding your own keys, backing up the 12 to 24 word seed phrase, and the tradeoffs of custodial accounts, phone wallets and hardware wallets.

Tom Scott visits Cloudflare's San Francisco office to show the wall of lava lamps whose camera feed is used as a source of entropy for random number generation. It is a short explainer on how this helps secure internet encryption.

Dr Mike Pound explains the suspected backdoor in the Dual_EC_DRBG random number generator and how elliptic curve constants could let someone predict its output.

Andreas Antonopoulos answers a Bitcoin Q&A question about energy consumption in mining. He argues that mining is arbitrage for the cheapest electricity, drives investment in renewables, and that the traditional financial system has hidden externalities.

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 short BicycleDutch episode showing how Dutch protected intersections continue cycle paths through the junction without needing extra street width.

A five-minute BicycleDutch episode showing how Dutch junctions are designed so cyclists and pedestrians can cross safely. It explains the layout choices that separate and protect them.

A short BicycleDutch episode showing how Dutch junctions with protected cycle paths are laid out. It argues these are proven, non-experimental designs that make intersections safer for cyclists.

Monty Montgomery of Xiph.org gives real-time demonstrations of sampling, quantization, bit depth and dither using real audio equipment, including both digital analysis tools and vintage analog bench gear. It shows that sampled audio is not stair-stepped and corrects common misconceptions about digital audio.

CGP Grey explains that the City of London is a tiny, separate entity with its own governance, history and privileges, distinct from the city called London. He covers its financial role and how it is run.

CGP Grey's six-minute explainer of the relationships the UK could have with the EU, based on Barnier's slide, shown as orbits of different closeness. It explains why the UK's red lines ruled out the closer options.

The first part of Extra History's animated miniseries on the South Sea Bubble. It explains how England's government debt led Robert Harley to turn to financier John Blunt, whose schemes began inflating artificial demand for shares.

Together Louisiana asks why Louisiana stays poor despite its natural resources and industry, focusing on industrial tax exemptions and corporate welfare.