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Real Engineering explains the materials science behind metal 3D printing, including crystal structure, laser sintering, and why printed parts develop fatigue cracks. It shows how process imperfections limit the strength of printed metal.

Tech Ingredients explains the principles of magnetohydrodynamics and builds several demonstrations, including propelling liquid metal and electrolytes with magnets and a railgun-style setup.

A short explainer on the physiological differences between fasting and simply eating less. It covers ketosis, ghrelin and hunger waves, and the hormonal effects of fasting.

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.

CGP Grey narrates an animated adaptation of Nick Bostrom's Fable of the Dragon-Tyrant. The story uses a dragon that demands a daily toll of lives as a metaphor for aging and society's acceptance of death.

Thunderf00t presents high-speed camera footage of alkali metals such as sodium and NaK reacting with water. The footage shows that the explosion is not caused by hydrogen ignition, as the usual explanation says. It is a Coulomb explosion driven by electrons leaving the metal.

A short animated explainer that stages a $100 footrace in which contestants start at different distances from the line, depending on the advantages or disadvantages they inherited. It uses the race as a metaphor for how unequal starting points shape outcomes, citing US census income and poverty figures.

An illustrated 23-minute summary of David Friedman's talk based on The Machinery of Freedom. It describes how law, police and courts could work as market services in a stateless society, covering private law, polycentric law and objections.

Kurzgesagt's short animated take on optimistic nihilism. It argues the universe has no inherent meaning, so we are free to create our own and enjoy life.

Kurzgesagt makes a selfish case for improving the world, arguing that helping people far away raises prosperity and innovation for everyone, including yourself. The animated video frames this as egoistic altruism and positive-sum cooperation.

Kurzgesagt's short animated video asks whether humanity should try to end aging, and argues the case for curing age-related disease. It is part one of a pair, with a second part by CGP Grey.

A short Healthcare Triage episode by Aaron Carroll arguing that milk gets an undeserved pass in efforts to improve diets. It examines claims about calcium and bone strength and concludes you don't need to drink milk.

Joseph Everett argues, drawing on the book The Salt Fix, that most people benefit from more rather than less salt, and reviews studies on sodium, potassium and blood pressure.

Ivor Cummins gives an 82-minute presentation on the history and science of vitamin D and human health. He draws on expert interviews to argue that sun exposure and vitamin D status are linked to many chronic diseases.

A video essay explaining hauntology, Mark Fisher's idea of lost futures, and 80s nostalgia. It uses the Fallout games and other media as examples of a retro-futurism that mourns futures that never arrived.

Joseph Everett compares the food environment of the US, with roughly 30% obesity, to Japan's, around 3.5%. He argues that what is available and normal to eat explains much of the gap.

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.

Practical Engineering gives a short introduction to concrete, covering the difference between concrete and cement, the ingredients, and reinforcement. It includes a hydraulic press demonstration of compressive strength.

A short excerpt from Frans de Waal's TED talk showing a capuchin monkey fairness experiment in which two monkeys are paid unequally, one with cucumber and one with grapes. The shortchanged monkey reacts angrily.

A Kurzgesagt explainer asking whether organic food is really healthier or better for the environment. It defines what organic means and looks at pesticide use, nutrition and environmental impact, with sources.

A School of Life short introducing Michel Foucault, who questioned assumed progress in how society treats madness, medicine and sexuality.

A Kurzgesagt animated explainer on meat: why people love it and what it costs animals, the environment and health. It lays out the complicated trade-offs of meat production and consumption.

CGP Grey's short explainer arguing that caffeine addiction is mostly harmless and may even be beneficial. It covers what caffeine does in the body.

Veritasium examines whether food has become less nutritious, weighing soil depletion, selective breeding and rising atmospheric CO2. It evidences nutrient decline even in weeds over a century and ties it to faster plant growth.

Vsauce explores qualia and whether different people experience colors the same way. It draws on color blindness, Mary's room, the explanatory gap and subjective experience.

A School of Life animated overview of Albert Camus, covering his existentialism and absurdism and his answer to the question of meaninglessness.

CGP Grey asks whether Star Trek-style teleportation would kill you and recreate a copy, working through the philosophy of identity and the Ship of Theseus. It is a short animated explainer.

A School of Life video arguing that everyone marries someone who is somewhat wrong for them, and that this is unavoidable. It is a four-minute version of an essay by Alain de Botton.

Casey Neistat's short New York Times op-doc investigating how accurate restaurant and packaged-food calorie labels really are. He gets items from chains like Chipotle, Starbucks and Subway measured by nutrition researchers and compares them to the printed numbers.

Thunderf00t applies a simple energy mass balance to weight loss, showing how much exercise is needed to burn off extra calories compared with eating less. He concludes that cutting intake is the easier route and that hunger fades after the first week.

Technology Connections takes apart a 1940s Sunbeam Radiant Control toaster. It senses the toast's own browning and lowers and raises it automatically using purely mechanical parts and no electronics.

A short Harvard animation narrated by Professor Rob Lue introducing mitochondria as the cell's powerhouses and how cells turn food and oxygen into energy.

An animated visualization of basic quantum mechanics using a free particle, with simulations based on the actual equations. It covers waves, particles, and how measurement collapses the wavefunction.

Veritasium explains why the kilogram is being redefined in terms of Planck's constant rather than a physical metal artifact. It visits NIST to show the Kibble balance and why measuring mass precisely is hard.

Robert Miles explains reward modelling, in which an AI learns what humans want from their preference comparisons instead of a hand-written reward function. He walks through the 2017 paper on deep reinforcement learning from human preferences.