(OK, it’s Thursday, but this was supposed to run on Tuesday but didn’t, owing to operator error)
A Clever Rube Goldberg Machine That Runs on Light
The amplified light fuels a number of different elements like a tub of water and a marble moving down a chute, but it all keeps coming back to optics.
(Nit: it’s not amplified, just focused at various points)
The idea that measurement changes what is being measured is the observer effect, not the Heisenberg Uncertainty Principle. A video explaining the HUP.
Another of Lyons’ themes in the article is to address the rather arbitrary “five sigma” (5σ) significance traditionally required by particle physicists to claim a discovery of a new particle or some other new effect.
This is often presented just as physics requiring 5σ, but Butterworth is a physicist and knowns that it’s not true in all sub-disciplines.
Having some more fun with my thermal camera (after a cold kept me from it for a bit). I had noticed that my lunch did not show up while being microwaved, because long-wave IR generally doesn’t pass through glass — here’s another image confirming this
You can’t see the thermal signature of my hand that’s behind the window. This is, of course, responsible for the greenhouse effect — visible light goes in but thermal IR does not leave, making the greenhouse (or your car, or, with a more wavelength-selective effect, the planet) get hotter.
I wanted to see if I could find anything that was transparent. I checked the transmission of sapphire and discovered it was a possibility — the transmission cutoff is out at 5 microns. Alas, the windows were opaque, meaning either that the windows I looked at were antireflection-coated (a distinct possibility), or that the bolometer sensors aren’t sensitive at the shorter wavelengths. But the plastic bag this window is in transmits just fine!
It’s probably made of polyethylene, which has good transmittance in much of the thermal range — just a few absorption lines (at about 3.5, 6.5 and 13 microns). We happen to have some 1/16″ thick poly sheets, we use for our air sled to allow it to work over porous surfaces, and are opaque to visible light. But not to thermal IR!
You can see a couple of spots where I touched the sheet with my fingertips and warmed it up, but in the picture my hand is behind the sheet and not touching it.
Through the Cracks Between Stars
Paglen ended his lecture with an amazing anecdote worth repeating here. Expanding on this notion—that humanity’s longest-lasting ruins will not be cities, cathedrals, or even mines, but rather geostationary satellites orbiting the Earth, surviving for literally billions of years beyond anything we might build on the planet’s surface
Neat image of the geostationary dots in a long exposure that shows the background stars’ apparent motion.
A red hot ball of nickel dropped into liquid nitrogen.
A few posts back I was concerned with optimising the WiFi reception in my flat, and I chose a simple method for calculating the distribution of electromagnetic intensity. I casually mentioned that I really should be doing things more rigorously by solving the Helmholtz equation, but then didn’t. Well, spurred on by a shocking amount of spare time, I’ve given it a go here.
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It turns out that the Helmholtz equation can also be applied to the modelling of the forced vibrations of the square plate, where the choice of conditions above equates to applying a force at the centre of the plate and clamping the edges. The rice/sand/etc settles at the nodes of the plate, i.e. the positions which stay stationary in the oscillation.
Physics demonstrations: Faraday disk
By turning a hand crank, one rotates a copper disk between a pair of magnets (the black disks), one generates an electrical current that runs from the outer edge of the disk to the central axis. Wires connected to these two points runs to the red and black plugs, through which one can measure the voltage difference generated. It isn’t a spectacular amount — I measured about 5 millivolts, max — but it demonstrates the phenomenon known as rotational electromotive force.
Finally got my FLIR One thermal-IR camera working (the issue was with the phone to which it’s attached), and it’s amazing.
This is my kitchen sink, with a bowl full of room-temperature water in it, along with some utensils, and the water on hot, aimed so it hits the basin rather than going straight into the drain.
