difference engine

Scott Manley explains the plumbing of rocket engines, including pressure-fed, gas generator, expander and staged combustion cycles. He shows why more complex designs exist and what they gain.

A Tom Scott guest video by Grady Hillhouse of Practical Engineering on the 1981 Hyatt Regency walkway collapse. A seemingly minor change to the support design led to catastrophic failure, which is why the case is taught as a lesson to check and double-check everything.

Kurzgesagt explains stellar engines such as the Shkadov thruster and Caplan thruster, which could move the Sun and solar system across the galaxy over millions of years to avoid hazards and reach new regions.

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.

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.

Practical Engineering explains Mechanically Stabilized Earth, where layers of reinforcement make soil strong enough to hold heavy loads, shown with a sand structure supporting a car. It notes that MSE walls are everywhere in infrastructure.

Real Engineering examines whether greening the Sahara could draw down carbon and slow climate change. It concludes that the effort would be enormously costly and that changes in albedo and other effects undercut the climate benefit.

Everyday Astronaut explains the basic physics of rocket engines, the main engine cycles and fuel types, then compares SpaceX's methane-fueled full-flow staged combustion Raptor to other engines. It runs nearly 50 minutes with chapter markers.

Tom Scott tells how John Reber's plan to dam San Francisco Bay was disproved by the Army Corps of Engineers' giant hydraulic Bay Model in Sausalito. The model showed the plan would have been dangerously wrong.

Kurzgesagt's animated explainer on CRISPR gene editing, covering how the technology works and what it could mean for curing disease, designer babies and aging. It frames genetic engineering as an irreversible change coming to humanity.

A Kurzgesagt animation on using gene drives to modify mosquitoes against malaria, and whether we should. It explains the mechanism and the ethical trade-offs.

A short video explaining the Intel Management Engine, a hidden embedded computer inside Intel machines with deep access to hardware. It is presented from an insider's perspective and raises backdoor and NSA concerns.

Bill Hammack of Engineer Guy explains the engineering behind the aluminum beverage can: why it is cylindrical, how it is manufactured, why it narrows at the top, the double seam, and how the pull tab works.

Bill Hammack of engineerguy uses slow motion video to show how the IBM Selectric typewriter works. He focuses on its fully mechanical digital-to-analog converter, which turns key presses into rotation of the type ball.

Practical Engineering explains pumped storage hydropower, which makes up most grid-scale electricity storage. It covers how it works and why it fits only certain geographies.

Real Engineering analyzes whether electric planes are feasible, focusing on battery energy density limits compared with jet fuel. It concludes electric flight works mainly for short ranges.

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 explains what a 100-year flood actually means, combining statistics, hydrology and how society treats risk. Grady walks through local drainage infrastructure and the caveats in estimating flood probability.

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.

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.

Tom Scott-style absurdist tour by Tom7 of SIGBOVIK chess projects: a tournament of 30 weird chess algorithms used to rate a color- and piece-blind chess program. Topics include mirrors, arithmetic encoding, perverted game tree search and a diluted Stockfish.

Veritasium explores compliant mechanisms, devices that move by flexing rather than using hinges and joints, with researchers at BYU. It covers advantages such as fewer parts and precision, including uses in nuclear weapon safety.

A short Boeing-supplied clip where the 737 MAX program's chief project engineer explains how the lengthened landing gear of the MAX 10 folds up. It shows the gear model in motion.

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.

Destin Sandlin of Smarter Every Day explores how grain bins work and the engineering and know-how involved in farming. His point is that farmers are exceptionally capable.

The first of four short videos from Bill Hammack (engineerguy) introducing and giving the history of a 100-year-old mechanical computer, Michelson's harmonic analyzer. The series goes on to explain Fourier synthesis, analysis and operation of the machine.

Real Engineering explains how Zipline built a drone delivery network for medical supplies in Rwanda. It covers the fixed-wing drones, catapult launch, parachute drop and the logistics behind the service.

Engineering Explained works through whether electric cars are really worse for the environment than gasoline cars. It covers battery production emissions, the electricity mix used to charge, and how long an EV takes to break even on lifetime emissions.

Real Engineering examines the efficiency of hydrogen as an energy carrier. It follows production, storage and fuel cell conversion losses and compares hydrogen cars with battery electric vehicles.

Real Engineering explains why SpaceX is building Starlink, including the economics of satellite internet. It covers the latency advantage of light in vacuum over fiber for long-distance links.

Real Engineering looks at the numbers for running California on renewables, focusing on the large energy storage needed. It argues about the cost of batteries and the role of other sources.

Engineering Explained uses physics to show why today's electric cars, including Teslas, are poor at towing, pointing to battery energy density and weight. It examines Cybertruck and F-150 towing claims.

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.

A 1936 Chevrolet-sponsored film that explains how a car transmission works by treating gears as spinning levers. It uses physical models to make the mechanism clear.

A short Wendover Productions explainer on ETOPS, the rules that let twin-engine jets fly long routes over oceans. It covers the economics that favored twinjets like the 787 over four-engine aircraft like the A380 and 747.

Veritasium rides a boat across the Los Angeles reservoir covered in 96 million black plastic balls. He explains why they were really introduced, which was not primarily to reduce evaporation.

A Kurzgesagt animated explainer on how humanity could build a Dyson sphere, a swarm of structures capturing the sun's energy. It covers using Mercury's materials and a step-by-step construction approach.

Dave Jones of EEVblog debunks the Solar Roadways project, which raised millions through Indiegogo and government funding. He works through the solar generation and LED power calculations to show the idea isn't viable.

Tom Scott visits ThyssenKrupp's test tower in Rottweil to see the Multi, a rope-free elevator that uses linear motors to move cabins sideways as well as vertically.

CGP Grey's video "Humans Need Not Apply" argues that automation will make a large part of the workforce economically obsolete, much as engines did for horses. It surveys robots and software replacing both physical and mental labor.