refrigeration cycle

FortNine surveys motorcycle airbag technology and explains why airbags have not reached mainstream adoption. It breaks down gear such as the Helite Turtle, Dainese D-Air and Alpinestars Tech-Air.

Arend Schwab demonstrates a research bicycle, the two-mass-skate design, that balances itself without gyroscopic effects or trail. It challenges the common explanations for why a moving bicycle stays upright.

FortNine looks at why Tesla Autopilot has rear-ended motorcyclists, speculating that the vision system misreads motorcycle taillights as a distant car. It argues that radar and other sensors would help.

A short BicycleDutch episode showing Vredenburg in Utrecht, the busiest cycle path in the Netherlands, with about 37,000 cyclists passing on a working day.

A short clip of Steve Jobs describing the computer as a bicycle for the mind. He compares human efficiency of travel to what computers do for mental work.

Ed March rides a Honda C90 through Iran on his journey from Malaysia to the UK, showing the country and its people. He argues Iran is far more welcoming than the press suggests.

Mathologer explains epicycles and complex Fourier series, inspired by an animation of Homer Simpson drawn with epicycles. It covers the shape of the Moon's orbit around the Sun and how to make your own epicycle drawings.

An animated 44-minute summary of Ray Dalio's book Principles for Dealing with the Changing World Order. It lays out the Big Cycle of rising and declining nations, covering debt cycles, internal conflict, and shifts in global power over the past 500 years.

FortNine argues that e-bikes have injury rates and speeds closer to motorcycles than to pedal bikes. It argues riders should treat them with similar safety gear and caution.

A motorcycle safety video on the SMIDSY (sorry mate, I didn't see you) accident, explaining the perception and optical illusion that makes drivers fail to see riders, and how riders can spot the signs and avoid it.

Destin of Smarter Every Day learns to ride a bicycle whose steering is reversed, taking about eight months, and compares it with how his young son learned much faster. It illustrates knowledge versus understanding and brain plasticity in adults versus children.

A short animation reconstructing a planet's looping orbit using Ptolemy's epicycles and deferents, with the epicycles tracing out the face of Homer Simpson. It shows how enough circles can reproduce nearly any shape.

Nine minutes of unedited footage of a very busy bicycle and car crossing at Korte Prinsengracht and Haarlemmerstraat in Amsterdam. Cyclists, pedestrians and cars flow through without traffic lights.

A short minutephysics video explaining why bicycles stay upright. It looks at gyroscopic precession, head angle and centre of mass, and shows that bikes self-steer toward the direction they lean.

Biochemist Nick Lane gives a Royal Institution lecture arguing that the Krebs cycle is central to what makes cells alive, not just genetic information. He draws on the themes of his book Transformer to link metabolism to the origin of life, death, and aging.

Google Netherlands' April Fools' 2016 video presents a fictional self-driving bicycle for Amsterdam, framed as a serious product launch.

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 sped-up two-minute view of morning rush hour at a busy Utrecht junction, where thousands of bicycles and buses pass each day. It illustrates a city where about a third of trips are by bike.

FortNine's tongue-in-cheek guide to why drivers fail to see motorcyclists and how riders can make themselves more visible. It touches on perception psychology, including the role of saccades.

A two-minute minutephysics video explaining why turning a bicycle requires first steering briefly the other way. It covers counter-steering and balance with slow-motion footage and 3D animation.

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

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.

Ray Dalio's 30-minute animated video explains how the economy works through credit, debt, interest rates, and short- and long-term cycles. It is based on his template for understanding the economy.

Technology Connections explains how heat pumps work as reversed air conditioners and why they can deliver several times the heat of resistive heating per unit of energy. It also tackles common myths such as poor cold-weather performance.

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.

California Superbike School demonstrates its 'No B.S.' bike, which has fixed handlebars so riders can only steer with body lean. It illustrates how little control that gives compared with countersteering.

Danny MacAskill tries to destroy carbon fiber bike wheels by riding trials tricks through downtown Glasgow, including on bare rims on concrete.

A rap battle in which John Maynard Keynes and F. A. Hayek debate the causes of boom and bust, stimulus, and bailouts. It was produced by Econstories to teach the two schools of thought.

Veritasium explains why bicycles are stable, arguing that gyroscopic effects are not the answer. The video shows countersteering and an experiment where riders blocked from steering the opposite way cannot turn.

FortNine explains the economics of the dealership model, arguing that dealers absorb inventory risk and help manufacturers' finances. It looks at whether cars and motorcycles could be sold more cheaply without them.

Dan Britt lectures on the history of climate, covering orbital cycles, ice ages and conditions millions of years ago. It frames current climate debate with deep-time context.

Copenhagen's bicycle ambassador Mikael Colville-Andersen argues in a TEDx talk that bicycle helmets threaten bicycle culture. He says they distract from road design and make cycling look dangerous.

Technology Connections explains in 33 minutes why thermoelectric (Peltier) cooling is far less efficient than compressor-based refrigeration.

Engineering Explained compares the lifecycle emissions of keeping an old car with those of buying a new, more efficient one. It weighs manufacturing emissions against emissions from driving, and covers gas versus electric cars.

An expat YouTuber in China shows how dockless bike-sharing, once loved, has been flooded by competing companies. Bikes pile up, get abandoned in odd places and are vandalised, with footage from around the city.

Not Just Bikes explains how an electric bakfiets (Dutch cargo bike) replaced the family car after a move back to Canada, saving thousands of dollars. It shows how much it can carry, including kids and groceries.

JerryRigEverything tours Li-Cycle to show how lithium-ion batteries from EVs, phones and tools are recycled. It walks through the process of shredding batteries and extracting materials.

Not Just Bikes explains why upright Dutch-style bicycles are comfortable and practical, and why they are rare outside the Netherlands.

AI Addict films a Tesla FSD Beta 8.2 drive through Oakland, annotating close calls, disengagements, pedestrians and wrong-lane moments with timestamps.