Popcorn pops because the water inside flashes to steam and expands. If you put the system under sufficient pressure it won’t do this … until the pressure is released, and all of the popcorn pops at the same time.
Category Archives: Tech
Watching the World Go By
A time-lapse taken from the front of the International Space Station as it orbits our planet at night.
via The Bad Astronomer, who makes a recommendation
Make sure you set it to the highest resolution, then make it full screen. You’re welcome.
It's Hammer Time, but I Can't Touch This
Enigma machine to go under the hammer
A version of the three rotor Enigma machine — used by the German military to encrypt messages, the code of which was subsequently cracked by a team at the legendary Bletchley Park complex — will be auctioned at Christie’s on September 29.
The last one sold for more than $100k, which is just a bit outside of my price range.
Six Impossible Things Before Breakfast
Perpertuum Mobile: The Quest for Perpetual Motion
In terms of the laws of physics, at least as we understand them in the early twenty first century, perpetual motion machines are impossibilities. However, a wide variety of machines, theories and devices have been developed and proposed over the years. Here’s a look at some of the more interesting ones here at Dark Roasted Blend.
If Wishes were Horsepower
Throw Me a Frikkin' Bone Here, People
BMW tests ‘1,000 times brighter’ laser headlights
The intensity of laser light poses no possible risks to humans, animals or wildlife when used in car lighting, BMW says reassuringly. The automaker says that’s because the laser light is first converted for use in road traffic, a bright, white that “is very pleasant to the eye.”
Maybe your eyes, but we’re not sure about everyone else’s. Did we mention laser headlights are 1,000 brighter than LEDs. Oh yeah. We did.
Yes, you did. Only that’s not what the BMW press release said. What they do say is
[L]aser lighting can produce a near-parallel beam with an intensity a thousand times greater than that of conventional LEDs. In vehicle headlights, these characteristics can be used to implement entirely new functions. Also, the high inherent efficiency of laser lighting means that laser headlights have less than half the energy consumption of LED headlights. Simply put, laser headlights save fuel.
So the observation is that lasers are 1000 times brighter than LEDs, which gets contorted into the claim that the headlights are 1000 times brighter. But they won’t be using as many lasers as LEDs — the goal is to save on energy use. The bottom line here is that laser diodes are more efficient at generating light than LEDs. You would lose that energy savings if for some reason you simply turn the brightness up to eleven.
A single statistic will make this clear: whereas LED lighting generates only around 100 lumens (a photometric unit of light output) per watt, laser lighting generates approximately 170 lumens.
For comparison, in generating white light the best you can do is about 250 lm/W. Presumably you would be using the same technology (phosphor or something else) to generate the white light, so you have to be more efficient at generating the photons.
The way you do this is by making more efficient use of the light. Laser diodes are LEDs with mirrors at both ends of the material, fashioned from cleaving the material — you get reflections whenever you pass from one medium to another with a different index of refraction. You can enhance or suppress this with the appropriate coating; high-power lasers will have a good reflector on one end of the lasing cavity and an anti-reflection coating on the other. Without the mirrors the light from the electrons spontaneously dropping down from one energy band to another can go in all directions. The mirrors allow for stimulated emission, and that will give you gain for photons that can reflect off the mirror and make another pass (or more) through the material. This means you are wasting a much smaller fraction of the photons to spontaneous emission. If you do something to the facets and interrupt the ability to lase (and I’ve seen this), the device reverts to just being an LED. One shortcoming is that laser diodes generally have a shorter lifetime than LEDs — they are static-sensitive and the coatings age — so for this to be viable there has to be the expectation that the lasers will last for several years.
One Small Step for an Android
One small leap for running robots
Unlike what we see at the movies, current bipedal robots are a long way from outrunning humans and leaping onto buildings.
In fact, says Wyeth, the fastest running robot does little more than a “quick shuffle”.
“Technically it is running because both feet are in the air, but only very briefly,” says Wyeth.
“Most two-year-olds could pretty effectively outrun these robots.”
Better Than a Flight Simulator
A micro camera is installed onboard an r/c plane F-16. The camera transmit live the video to ground and I wear video goggle to fly the plane in real time like if I was in the cockpit. The camera replace the head of the pilot and the movement of the cam is control by the movement of my head on ground via a head mount gyroscope (head tracker)
Nudge, Nudge. You've, Y'know, Done it …
What’s it like?
This is what it’s like to be shot at with an AK-47
Trent Kimball, CEO of Texas Armoring Corporation (TAC), was tired of customers asking if his company’s bullet-resistant glass in its armored cars actually resisted bullets. So he did what any reasonable CEO would do: he asked his employee to shoot at him with an AK-47. It’s loud, scary, dangerous, and completely awesome.
James Bond Never Needed This
But I could totally see Mission:Impossible doing it. Spy vs. Spy: Casinos Can’t See The Cameras Hidden Up Gamblers’ Sleeves
In January, at the newly opened $4-billion Cosmopolitan casino in Las Vegas, a gang called the Cutters cheated at baccarat. Before play began, the dealer offered one member of the group a stack of eight decks of cards for a pre-game cut. The player probably rubbed the stack for good luck, at the same instant riffling some of the corners of the cards underneath with his index finger. A small camera, hidden under his forearm, recorded the order.
After a few hands, the cutter left the floor and entered a bathroom stall, where he most likely passed the camera to a confederate in an adjoining stall. The runner carried the camera to a gaming analyst in a nearby hotel room, where the analyst transferred the video to a computer, watching it in slow motion to determine the order of the cards. Not quite half an hour had passed since the cut. Baccarat play averages less than six cards a minute, so there were still at least 160 cards left to play through. Back at the table, other members of the gang were delaying the action, glancing at their cellphones and waiting for the analyst to send them the card order.