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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.

Ward Cunningham explains the history and intent of the debt metaphor, which he coined while refactoring the WyCash product. He says debt means code reflecting an incomplete understanding of the problem, not sloppy programming.

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.

A Vsauce video exploring whether chairs exist, through metaphysics, mereology and the philosophy of categorizing objects. It runs about 38 minutes and cites academic work on ontology.

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.

Kurzgesagt explains why exercise alone does little for weight loss, since the body compensates by adjusting its total energy expenditure. It argues exercise is still very valuable for health.

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.

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.

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.

Technology Connections explains how the simple American drip coffee maker works, including the bimetal valve and bubble-pump heating, and compares the original Mr. Coffee with modern machines.

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.

A two-minute animation of an Alan Watts talk arguing that life is like music: it is meant to be danced to in the moment, not rushed toward a final goal. It is a short, accessible take on living in the present.

Joseph Everett, with Dr. Frank Mitloehner, argues that eating less meat will not do much for the climate. He covers beef's water footprint, land and feed use, and methane.

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.

Adam Ragusea examines whether olive oil is unsafe for high-heat cooking and whether it tastes bad when heated. He cites studies showing it is among the most stable cooking oils and that smoke-point worries are overblown.

Mark Rober makes a plant-based burger for Bill Gates and explains why meat production strains the environment. Gates also appears and discusses his worry about steel and cement.

A What I've Learned video arguing that industrial seed and vegetable oils have displaced saturated fats and harmed health. It covers the history of vegetable oils, the American Heart Association's role, and rising consumption.

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.

Veritasium explains how Penrose tilings and quasicrystals overturned the belief that 5-fold symmetry and non-periodic crystals were impossible, including an interview with Paul Steinhardt.

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.

A Kurzgesagt video on the conditions in which most farm animals are raised. It argues that cruelty is for cheaper rather than better meat, and that a small price increase per meal could avoid most of the suffering.

Veritasium explains how jet engines run hotter than their components' melting points, using cooling air and single-crystal superalloy turbine blades. It covers how the blades are grown as aligned crystals.

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.

Alex O'Connor shows that ChatGPT cannot draw a wine glass filled to the brim, and ties the failure to David Hume's missing shade of blue. It asks what the failure says about how image models learn.

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.

Tom Scott visits the Swiss Military Museum to see the last surviving 1970s tank-driving simulator. It uses a real camera moving over a miniature model landscape rather than any computer graphics.

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

Destin Sandlin of Smarter Every Day explores molten glass and Prince Rupert's drops with a glass artist, including a process that freezes the moment glass shatters and an artisan who makes the drops.

A Kurzgesagt animated explainer on the climate and environmental cost of meat. It covers how beef drives deforestation and emissions, and how this compares with plant-based foods.

Dr. John Campbell reviews studies on vitamin D deficiency and immunity, including links to influenza and COVID-19, with Public Health England advice. He walks through the sources he cites.