electromagnetism

Veritasium explains magnetism as a consequence of special relativity. Length contraction of moving charges makes a current in a wire attract or repel a nearby moving charge.

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.

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.

ElectroBOOM's Mehdi Sadaghdar responds to Veritasium's lamp-and-long-wire puzzle, analysing it as an electrical engineer. He covers where the original framing misleads and the role of stray capacitance.

Veritasium explains why a halved grape in a microwave makes plasma: the grape traps microwaves, and the fields of two halves interact to concentrate energy where they touch.

AlphaPhoenix builds a scaled-down version of the Veritasium electricity thought experiment using about a kilometer of wire and an oscilloscope. He measures how the signal actually propagates and explains the result.

PBS Space Time argues that the speed of light is better understood as the speed of causality, the universal limit on how fast cause and effect propagate. Light travels at that speed because it is massless, but the limit itself is a property of spacetime.

Veritasium explains why the one-way speed of light has never been measured, only the round-trip speed, since measuring it requires synchronized clocks that assume the answer. It explores the implications for relativity.

The first of Richard Feynman's 1964 Cornell Messenger Lectures, The Character of Physical Law, focusing on the law of gravitation. Feynman builds up from planetary motion to the nature of physical laws.

A restored HD upload of the 1983 BBC series Fun to Imagine, in which Richard Feynman talks informally about everyday science. Topics include jiggling atoms, fire, rubber bands, magnets, electricity, mirrors, seeing, big numbers and ways of thinking.

ScienceClic explains why the rubber sheet analogy for general relativity is misleading and offers a new visualization that includes the curvature of time and shows gravity as motion through curved spacetime.

David Tong, a Cambridge theoretical physicist, explains at the Royal Institution that the fundamental building blocks of nature are quantum fields rather than particles. He covers what we know about these fields and how they fit into the Standard Model.

Physicist Carlo Rovelli gives a public lecture at the Royal Institution on how our understanding of time has changed, from Boltzmann and Einstein to quantum theory and loop quantum gravity. He blends physics, philosophy and art to argue that time is stranger than everyday intuition suggests.

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.

Sean Carroll introduces his video series on the biggest ideas in physics, such as symmetry, space and matter, as informal discussions with follow-up Q&A videos. This is the short opening video of the series.

A 1983 BBC interview in which Richard Feynman is asked how magnets work and explains why 'why' questions are hard to answer in everyday terms. He reflects on what counts as an explanation and the limits of analogy.

Physicist Angela Collier's roughly hour-long video on how string theory was hyped to the public and what that did to science communication. She traces the history of the theory as a narrative and argues it is interesting but was oversold.

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.

Veritasium explains, with expert input, that in general relativity gravity is not a force and objects follow straight paths through curved spacetime, including why standing on the ground means you are accelerating.

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.

PBS Space Time explains Noether's theorem: conservation laws such as energy and momentum are consequences of deeper symmetries. It also covers why those laws hold only under certain conditions.

A short clip of Richard Feynman answering an interviewer's question about why magnets repel, explaining that a 'why' question depends on a shared framework of understanding. It illustrates how hard it is to explain fundamentals to a layperson.

Veritasium explains the effort to redefine the kilogram, which was still defined by a physical artifact, and how a near-perfect silicon sphere from the Avogadro project helps. It also covers the history of the unit's odd naming.

A clip from the 1983 BBC series Fun to Imagine in which Richard Feynman explains heat as the jiggling of atoms and how we perceive it as hot and cold.

Harvard Belfer Center lecture by Matthew Bunn explaining how nuclear bombs work, including fission and fusion weapons and which parts of bomb-making are hard. It is part 1 of 2 in the Nuclear 101 series.

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 explainer on entropy, presented as one of physics' most important and least understood concepts. It uses examples such as heat engines and the sun's energy flowing through the Earth.

A PBS Space Time episode explaining how space and time swap roles inside a black hole's event horizon. It is part of the channel's black hole series.

Real Engineering's Brian McManus explains Helion's approach to nuclear fusion: colliding two plasma rings, compressing them magnetically, and capturing energy directly from the changing magnetic flux rather than boiling water. It covers why this pulsed design sidesteps problems of tokamaks and laser fusion.

Lex Fridman interviews Stephen Wolfram for about three hours on cellular automata, computation, the Wolfram Physics Project and his career with Mathematica and Wolfram Alpha.

Veritasium explains what a black hole should look like, using J.P. Luminet's 1979 work and a cardboard 3D model to show how light bends around it. It was made just as the first black hole image was released.

Physicist Geoffrey West speaks at an FQXi conference on time about complexity and scaling laws. He covers how metabolism, growth and lifespan scale across organisms and how the same mathematics applies to cities and companies.

Eric Weinstein's roughly three-hour presentation of Geometric Unity, his proposed theory unifying physics, given as a special episode of The Portal. It includes clarifications at the end.

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.

A PBS Space Time episode asking what matter, mass, and energy really are, starting with inertial versus gravitational mass and what mass-energy equivalence means.

A 78-minute Richard Feynman lecture of anecdotes about working at Los Alamos on the Manhattan Project, followed by about ten minutes of audience Q&A in which he tells three safe-cracking stories.

A long Lex Fridman interview with Stephen Wolfram on complexity, cellular automata, computational irreducibility and the Wolfram Physics Project.

Max Tegmark's MIT CBMM talk on why deep learning works so well. He argues that the laws of physics and the symmetries in physical data make it compressible into small neural networks, tying physics to network structure.

PBS Space Time introduces Miguel Alcubierre's warp drive, explaining how spacetime itself could be warped rather than moving a ship through it, and whether it is physically possible.

3Blue1Brown explains how holograms record a 3D scene on 2D film, using wave diffraction and phase. The video includes demonstrations of several real holograms.