walter lewin did something like that too
Just another blog on physics and for me to share my findings
walter lewin did something like that too
NPR’s Skunk Bear Tumblr has a great new video on the schlieren visualization technique. The schlieren optical set-up is relatively simple but very powerful, as shown in the video. The technique is sensitive to variations in the refractive index of air; this bends light passing through the test area so that changes in fluid density appear as light and dark regions in the final image. Since air’s density changes with temperature and with compressibility, the technique gets used extensively to visualize buoyancy-driven flows and supersonic flows. Since sound waves are compression waves which change the air’s density as they travel, schlieren can capture them, too. (Video credit: A. Cole/NPR’s Skunk Bear)
When light travels through areas of different air density, it bends. You’ve probably noticed the way distant pavement seems to shimmer on a hot day, or the way stars appear to twinkle. You’re seeing light that has been distorted as it passes through varying air densities, which are in turn created by varying temperatures and pressures.
Schlieren Flow Visualization can be used to visually capture these changes in density: the rising heat from a candle, the turbulence around an airplane wing, the plume of a sneeze … even sound. Special thanks to Mike Hargather, a professor of mechanical engineering at New Mexico Tech, who kindly provided a lot of these videos.
I’m totally Schlieren right now. Amazing sights of sounds.
Want to know which elementary particle best describes you? Well this interactive quiz by the DESY research centre and Universum Bremen will show you based on how you see yourself.
* My top 3 particles were the gluon, tau neutrino, and up quark.
From the hand of Andrew Pontzen (@apontzen) and Tom Whyntie (@twhyntie) TED Ed bring us a divulgative introduction (the first in a series) about ‘The Fundamentals of Space-Time’. Very basic but pretty funny. Animation by Giant Animation Studios.
Smarter Every Day - 112 - Cold Hard Science: Slapshots In Slow Motion
New Video! Slow Motion Physics of a Slapshot!
GET SMARTER SECTION
The stick rigidity data collected by Dr. Evans and I is not a formal reflection on the manufacturers because the sticks were previously used and we could not find an ASTM standard to setup our test. The possibility exists that I put the support positions too close together, which would make the values lower. The players however gave us the sticks because they were “so used they were now flimsy”. Our data reflected this. If I had it to do over again I would test a new stick vs an old stick. Kettering University has done some research on this subject and we tried to setup our test apparatus similar to theirs. They applied the force to the foot of the stick. We applied the force to the center. http://www.kettering.edu/news/taking-stick-check
I thought this was a great video of a product that has normalized the process by constraining the 1 inch deflection measurement. https://www.youtube.com/watch?v=S2f7SQgn-9I
I shot the skaters with a Phantom MIRO LC320S made by Vision Research: http://www.visionresearch.com/Products/High-Speed-Cameras/Phantom-Miro-M320S/ Most speeds were around 3271 fps, but I shot the full body shot at 1200 fps.
Slow Motion sound design made by Gordon McGladdery, “A Shell In the Pit”. Gordon’s work is awesome, you should check it out. I like his music. http://ashellinthepit.bandcamp.com/
Hockey Stick Rigidity data plotted, and equations formatted into LaTeX format by Will Leahy: http://www.willleahy.info/
"Whippness" Graphic, and shear moment diagrams by:
Emily Weddle Design http://www.emilyweddledesign.com
With thanks to:
My friend Dr. Jeff Evans. Tenured Mechanical Engineering professor at UAH
UAH Director of Hockey Operations Nick Laurila
The nameless UAH Hockey player
Gravitational Wave Discovery! Evidence of Cosmic Inflation
Join Derek from Veritasium and take a look at the universe’s adorable baby photos! Aww, who’s a cute widdle universe? YOU ARE! You’re growin up sooooo fast with your inflation, yes you are!!
Smoooshybooshybooboo look how homogenous that made your cosmic background radiation! And those cute little gravity wave lumps, d’awwww, I hope you never lose those.
(I’m baby talking the Big Bang. I think I should get some fresh air.)
A core-collapse, or Type II, supernova occurs in massive stars when they can no longer sustain fusion. For most of their lives, stars produce energy by fusing hydrogen into helium. Eventually, the hydrogen runs out and the core contracts until it reaches temperatures hot enough to cause the helium to fuse into carbon. This process repeats through to heavier elements, producing a pre-collapse star with onion-like layers of elements with the heaviest elements near the center. When the core consists mostly of nickel and iron, fusion will come to an end, and the core’s next collapse will trigger the supernova. When astronomers observed Supernova 1987A, the closest supernova in more than 300 years, models predicted that the onion-like layers of the supernova would persist after the explosion. But observations showed core materials reaching the surface much faster than predicting, suggesting that turbulent mixing might be carrying heavier elements outward. The images above show several time steps of a 2D simulation of this type of supernova. In the wake of the expanding shock wave, the core materials form fingers that race outward, mixing the fusion remnants. Hydrodynamically speaking, this is an example of the Richtmyer-Meshkov instability, in which a shock wave generates mixing between fluid layers of differing densities. (Image credit: K. Kifonidis et al.; see also B. Remington)
You know it’s spring when, just after sunset, the refrigerator constellation rises in the western sky.
(But seriously, remember that our perspective on the stars is at the same time wonderfully unique but not at all special, and the stellar stories that we write are products not only of our imaginations, but also our brain’s relentless desire to recognize patterns in random assortments of far away dots)