This idea that nature is inherently probabilistic — that particles have no hard properties, only likelihoods, until they are observed — is directly implied by the standard equations of quantum mechanics. But now a set of surprising experiments with fluids has revived old skepticism about that worldview. The bizarre results are fueling interest in an almost forgotten version of quantum mechanics, one that never gave up the idea of a single, concrete reality.
The experiments involve an oil droplet that bounces along the surface of a liquid. The droplet gently sloshes the liquid with every bounce. At the same time, ripples from past bounces affect its course. The droplet’s interaction with its own ripples, which form what’s known as a pilot wave, causes it to exhibit behaviors previously thought to be peculiar to elementary particles — including behaviors seen as evidence that these particles are spread through space like waves, without any specific location, until they are measured.
Particles at the quantum scale seem to do things that human-scale objects do not do. They can tunnel through barriers, spontaneously arise or annihilate, and occupy discrete energy levels. This new body of research reveals that oil droplets, when guided by pilot waves, also exhibit these quantum-like features.
Elementary Mechanics from a Mathematician's Viewpoint [direct link to large PDF] by Michael Spivak - notes from his eight 2004 lectures (which eventually became a book). See the quote inside to get the flavor of it. [more inside]
What would happen if a cue ball struck a rack of 15 perfectly round, frictionless billiard balls, exactly head-on?
As Teahupo'o gains notoriety as one of the biggest monsters in the surfing world, the tiny area it covers gets more and more crowded. If you want to dig some fingernail-marks into the armrests of your chair, watch 2013's Inside the Monster (25:43, French with English Subtitles). Then, explore The Mechanics of Teahupo'o in this slideshow about what makes this slab tick. [previous, previous]
Major bicycle tools manufacturer Park Tool maintains a neatly sorted bevy of repair, maintenance and technical information articles. Their lead mechanic Calvin runs a video channel that includes -- among many other things -- on-the-road bicycle repair tips. Even more bike info (new bike assembly procedures, road and mountain bike positioning charts, thread concepts, drive train troubleshooting, etc.) is available on the miscellaneous topics page. Don't forget to check out the bicycle mechanics language spreadsheet!
Photographer Anthony Kurtz visited Femme Auto in Senegal and took portraits of the mechanics and auto body workers there. They're really gorgeous shots, and it's always great to see badass women doing it to it in a male dominated field. (Via)
The Royal Spanish Library has put online today an interactive version of Leonardo da Vinci's Madrid Codices I & II. There are transcriptions of the text (in Spanish and Italian, click "T" on the bottom menu), animations of many of the mechanical contraptions (click play button "ver animacion") and the "Indice" in the bottom menu organizes the folios by theme.
How a watch works in the clear, precise 1949 informational style.
The great[pdf] Russian mathematican Vladimir Igorevich Arnol'd, foremost modern practitioner of classical mechanics, influential teacher, namesake of a minor planet, and semi-nude cross-country skier has died.
Steve Durnin's D-Drive is a fascinating new infinitely-variable transmission that doesn't use friction components or a clutch of any kind. Video of a prototype with detailed explanations is included.
The Mechanical Universe...and Beyond is a critically-acclaimed series of 52 thirty-minute videotape programs covering the basic topics of an introductory university physics course. This well produced and highly informative 52 episode series, hosted by David Goodstein of Caltech, is available as Video on Demand (Note: simple registration required to view videos). [more inside]
Physicists have 'solved' mystery of levitation Professor Ulf Leonhardt and Dr Thomas Philbin, from the University of St Andrews in Scotland, have worked out a way of reversing ... the Casimir force, so that it repels instead of attracts. Their discovery could ultimately lead to frictionless micro-machines with moving parts that levitate. But they say that, in principle at least, the same effect could be used to levitate bigger objects too, even a person.
Reversible flow! In the 1960s, the National Committee for Fluid Mechanics Films produced a series of films for education in fluid mechanics. This clip is part of "Low Reynolds Number Flow"; you can find the entire collection streamed here. Interesting demonstrations abound. (1st link is QT; rest are RealPlayer.)
The astronomical clock in the French city of Besancon is quite a mechanical marvel. Built in 1860, its inner workings are comprised of more than 30,000 interoperating pieces, driving 37 separate clockface gauges. It is one of the finest intersections between art & mechanics that I've ever come across.
Does dark matter exist? Dark matter has been suggested as a solution to the galaxy rotation problem where individual stars don't seem to rotate the way Newton's laws would predict. Now, some scientists are saying that observations fit with Einstein's general relativity, without any dark matter needed. I just find it amazing that no one has tried this yet.
Machine by SymmetryLab: fixed points, spinners, pistons, elastics, and connectors. Dig the frictionless world.
SymmetryLab's other stuff is noteworthy as well.
SymmetryLab's other stuff is noteworthy as well.
An Industrial Art Gallery Is it just me, or do you find hand-drawn mechanical diagrams capturing concepts of physics strangely soothing?
How engines work. This isn't new but it's a great resource for the mechanically minded and the mechanically challanged as well. It includes animations and step by step descriptions of how most existing engines work, from Steam Locomotive to Jet Propulsion. Simple yet informative.
Really, really nice... lots of lovely devices...