acoustics

A choral recording by Cappella Romana from the album Lost Voices of Hagia Sophia. It is part of a project recreating Byzantine chant using the acoustics of the Hagia Sophia.

Smarter Every Day shares a binaural audio recording of the SpaceX Falcon Heavy launch made by Trevor Mahlmann, with explanations of the sounds including the sonic booms of the landing boosters. It is meant to be heard with headphones.

A BBC Earth clip from Super Powered Owls in which the team uses sensitive sound equipment to compare owl flight with other birds. It shows why owls fly almost silently.

Alvin Lucier's 1969 minimalist piece in which a spoken text is repeatedly played back and re-recorded in a room until the room's resonances replace the words. This is the 1981 Lovely Music recording.

A five-minute demonstration of the Shepard tone, an audio illusion made from octave-separated tones that makes pitch seem to rise endlessly without ever getting higher.

Tech Ingredients builds a pair of large Voigt speakers and explains ported, transmission line and horn designs. It tests them in an anechoic chamber and uses constrained layer damping for the enclosure.

A performance recording of Alvin Lucier's 1969 experimental piece in which a spoken text is repeatedly played back and re-recorded in a room until the room's resonances overwhelm the words. It is a landmark of electronic and conceptual music.

A Bell Labs film in which Dr. J.N. Shive uses a mechanical wave machine to demonstrate reflection, standing waves, resonance and impedance matching. He includes some equations but relies mostly on real-world examples a layperson can follow.

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.

A short clip from a Richard Feynman interview in which he explains fire, describing how burning wood releases sunlight stored by the tree, which built itself mostly from air. It showcases his curiosity and plain-spoken explanations.

DIY Perks builds a realistic artificial sun for dark winters, using a powerful water-cooled LED, a satellite dish reflector for near-parallel rays, and a scattering layer to mimic the blue sky. The video explains the optics behind why most lamps do not look like sunlight and shows the build and its results.

Technology Connections explains why brown is not a spectral color but a context-dependent perception, essentially dark orange seen against brighter surroundings.

Veritasium argues that electric energy is carried by fields around the wires rather than by electrons moving through them, using a thought experiment with a large circuit.

Technology Connections explains how old-fashioned non-electronic rice cookers work, using a magnet and spring switch tripped by the Curie point. It shows the thermodynamics and magnetism behind a simple appliance.

AlphaPhoenix uses a custom high-speed measurement setup to watch voltage waves travel down wires and split at a fork. It answers how electricity knows where to go and how quickly that process happens.

Huygens Optics explains the Fourier transform and shows how a lens performs one optically. A DLP projector is used as a Fourier filter to do simple pattern recognition on lithographic character patterns.

3Blue1Brown visualizes Feynman's lecture on the refractive index, explaining why light appears to slow down in glass and why the effect depends on color. It builds the idea from waves produced by oscillating charges in the material.

A short video from the trafficwaves.org site showing how traffic jams and standing waves form, including the fight between cheaters and blockers at an exit-lane backup. It also touches on how individual driving behavior affects the flow.

Destin Sandlin of Smarter Every Day undergoes hypoxia training and experiences his own impaired thinking as oxygen is withdrawn. The video shows how quickly and unnoticeably oxygen deprivation degrades judgment, illustrating why you put your own mask on first.

Veritasium explains how trees lift water from roots to the top of tall trunks, using transpiration pull and the negative pressure that liquid water can sustain. It explains why trees do not need pumps or valves.

A Smarter Every Day episode from aboard a nuclear submarine on how the crew makes breathable air. It covers oxygen generation from seawater, oxygen candles and CO2 scrubbing with amine.

A PBS clip in which Richard Feynman explains the strange nature of light and electromagnetic radiation. He conveys how little of it we actually see and how radio waves are present everywhere.

Bill Hammack of engineerguy introduces his series on Michael Faraday's lectures on The Chemical History of a Candle. He describes the free companion book and the commentary and caption features that help modern viewers.

CuriousMarc powers up a vintage HP 5061A cesium beam clock and explains both the quantum principle and the HP implementation in detail. It is part of a longer atomic clock series.

Matthias Wandel uses anemometer measurements to find where to place a fan to move the most air through a house at night. He finds that placing the fan some distance back from the window works better.

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.

Veritasium's Derek Muller visits NASA JPL to see the Mars helicopter Ingenuity before it was mounted on the rover. He explains how it can fly in Mars's thin atmosphere with large, fast-spinning contra-rotating rotors and low mass, and covers power and cold.

Benn Jordan investigates infrasound and low-frequency noise from data centers, including xAI's Colossus and a crypto mine, and reports his own experiments on the effects. The video covers the health and community impacts on nearby residents.

Smarter Every Day films Prince Rupert's drops, tempered glass drops, in high-speed slow motion at 130,000 fps. It shows how the drop's heavy internal stress lets the head survive hits while the tail shatters the whole thing.

A minutephysics explainer showing that the Moon's path around the Sun is not a spiral but closer to a 12-sided polygon with curved corners. It argues the Moon arguably orbits the Sun rather than the Earth.

Veritasium shows silicone oil droplets bouncing on a vibrating bath, a physical analogue of pilot wave theory that reproduces quantum-like behavior such as double-slit patterns.

A short demo of a walking droplet on a vibrating silicone oil bath passing through a double slit and producing interference, a macro-scale analogue of pilot-wave behavior.

Destin Sandlin of Smarter Every Day explains Multi-Domain Operations through footage from his last mission at RIMPAC 2018. He covers missile and torpedo testing and interviews military leaders about the cyber and information domains.

OK Go's music video for Upside Down & Inside Out, filmed during parabolic flights so the band and performers are weightless in the plane.

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.

Veritasium asks people where a tree's mass comes from, then explains that most of a dry tree's mass originates from carbon dioxide in the air. It combines street interviews with a short explanation of photosynthesis.

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.

Retired Boeing Technical Fellow Doug McLean walks through common misconceptions in aerodynamics, drawing on his book Understanding Aerodynamics. He critiques popular explanations of wing lift and rocket thrust and argues for arguing from the real physics.

A short film made with cold neutron imaging at the Paul Scherrer Institut showing a moka pot brewing coffee, sped up four times. The neutron beam makes the water and steam inside the pot visible.

Tom Scott stands by a construction site and explains why reversing vehicles now use a white-noise hiss instead of beeping. The sound is easier to locate directionally and less annoying to neighbours.