Assembler is a new physics based wonder where you move some depository equipment to get your precious green crate in position. For what? No matter! Physics work perfect and the feel of grabbing and moving around things is just perfect. Don’t play too much or you’ll dream of dirty green crates flying around
Category Archives: Physics
Try to Set the Night on Fire
[R]esearchers describe a method for adding light-emitting elements in a precise way to a future photonic circuit. They filled a small hole in a silicon wafer with a liquid containing tiny chunks of fluorescent semiconductor and imaged the pattern of light that was generated. The technique permits easy removal and replacement of the fluorescent particles and offers a way of creating photonic structures that include light emitters set out in some desired pattern.
I'll Stop the World and Melt With You
Solar furnace. Cooks hot dogs, melts steel.
Dude, it's Physics, Part II
The Physics of Surfing (Part Two: Tubes and Barrels)
But why do some waves break as hollow grinding tubes while others crumble more gently and forgivingly? Let’s examine a little wave dynamics in order to assess the situation. Ocean waves are created by wind blowing over the ocean surface, as the kinetic energy of the air is converted into potential and kinetic energy of the water. The biggest and most powerful waves are created in massive storms. As the swells generated by these storms travel over the open ocean, the originally chaotic “victory at sea”-type wave motion is gradually organized into cleaner lines. As with all waves, it is not the actual material (water in this case) that travels any distance through the medium — it is the energy of the wave. As the wave energy passes through a point in the ocean, the water molecules rise and fall in a circular pattern but remain in the vicinity as the disturbance passes by.
Previously: Dude, It’s Physics
Billy Joel, in the Library, with the Lead Pipe
Mathematician Cracks Mystery Beatles Chord
The opening chord to A Hard Day’s Night is also famous because for 40 years, no one quite knew exactly what chord Harrison was playing. Musicians, scholars and amateur guitar players alike had all come up with their own theories, but it took a Dalhousie mathematician to figure out the exact formula.
Help Me, Obi Wan
General Kenobi, years ago you served my father in the Clone Wars. Now he begs you to help him in his struggle to explain what a hologram is, and isn’t.
I only watched a few minutes of CNN’s election coverage before becoming ill (figuratively) and switching off the TV, so I missed where he called their camera trick a hologram. But it wasn’t, and several people caught it.
So what happened?
CNN focused more than 35 high-definition cameras on Yellin to get multiple views from Grant Park in Chicago for the look of a 3-D holographic image Tuesday. That made it appear as if Yellin was in the studio talking with CNN anchor Wolf Blitzer.
That’s a camera trick, but not a hologram.
Unfortunately, some of the criticism misses the mark. Uh, Wolf, That CNN Election Image Wasn’t a Hologram
A hologram is a photographic image that is three-dimensional and appears to have depth. They work by creating an image composed of two superimposed pictures of the same object, but seen from different points.
No, but I think I can see how the writer got from what a hologram actually is to this explanation. A hologram is a comparison of an image with some reference light, not the comparison of two images. Some of the light bounces off of the target and then interferes with the reference beam (and I think this interference pattern is the “superimposed” reference), and you record the interference pattern on the film. That pattern has all the information of the object, and when you pass a reference beam through the film (or off the surface, if it’s a reflection hologram) you’ll see a 3-D image.
The CNN image wasn’t 3-D. It looked something that was 3-D on the TV screen, but like everything else on the screen, the image was 2-D.
CNN’s Hologram. Real or Fake? calls the CNN technique a tomogram, which I don’t think is right. Tomography gives you 2-D slices of a 3-D object, and that’s not what’s happening here.
CNN’s “Holograms” Aren’t Holograms, So Cut It Out doesn’t attempt an explanation of holography, and is content to note that
It was movie magic, folks, similar to what we all remember from The Matrix. Given that it was done live without a hitch, it was extremely way cool. But it wasn’t a hologram, and no amount of wishing will make it so.
Zapperz, in Not A Hologram, has linked to an article that lists other instances of people misusing “hologram”
Bartender, Gimme a Pan-Galactic Gargleblaster
Exploring Liquids: An Experiment
Fun, and physics, with fluids
Here’s a fun experiment you can try using the contents of your kitchen cupboard. Explore the effects of different densities and learn about refraction, viscosity and the planet Jupiter. You’ll need five different liquids; I used golden syrup, dishwashing liquid, water, alcohol and vegetable oil. I also used some food colouring to make it easier to see what was going on (and because the alcohol I use is Tequila which looks just like water). If you have a chopstick around that will also be handy – but any stirring implement will do.
Career Advice
Career Advice from Dr. Pion
Engineering and physics and programming are all hard work. Hard work can be fun, or it can be a drag. Money can make up for it being a drag, but many students who are just in it for the money will struggle with motivation when faced with the years of hard work that must be put in before you get that first internship, let alone a job.
There’s a good example that goes with this (posed as an exchange between a student and advisor) of why salary should not be the primary reason you choose a career.
So my advice is to learn everything you can from your classes, find what you like, find what you are good at, and pursue a career that requires skills that you have and enjoy doing for 10 or so hours a day. All technical careers are hard work for the money, so you better like what you are doing.
Relatively Special
Lorentz Transformations at Backreaction
Belated Conference Greetings
I’ve been seemingly running in quicksand ever since returning from the 7th Symposium on Frequency Standards and Metrology, what with the pileup of work while I was away (and everything seemingly breaking during that period of time) and getting ready for our clocks to leave the nest. But now, as I’m burning up my comp time from all that, I’ve had a chance to look back.
The conference was really good, as conferences go. A little over 100 people attended, from labs around the world. I knew perhaps a third of them already (though a few probably did not remember me) and met a few more. I didn’t see any glitches except for one or two instances of technical difficulties, which speaks volumes for the organizers and support staff, because you just know there were issues, and since they didn’t become visible it means they were solved quickly. The accommodations were very nice and the food was decent as far as dining hall food goes. The whole thing came in under the government-rate per diem, and the government is actually pretty stingy about such things.
Many of the talks encompassed the recent push into optical transitions for timekeeping; the microwave transitions used in the established clocks of today run at something a little less than 1010 cycles per second, but an optical transition will be about 4 orders of magnitude higher in frequency. Even if your detection can’t be done to the same level of precision, owing to lower light levels and fewer atoms, the higher frequency represents 2 or 3 orders of magnitude improvement in the overall measurement. The enabling technology for this has been the octave-spanning optical frequency comb, made by pulsed lasers in some nonlinear medium. If you consider the time width of the pulses Fourier-transformed in the frequency domain, you see a whole bunch of laser frequencies separated by the pulse repetition rate, so it looks like a comb. As I’ve mentioned before, you can use these individual frequencies to interrogate atoms, meaning you can measure some narrow clock transition. This becomes really useful when the comb spans an octave, so the low-frequency end can be frequency-doubled and referenced to the high-frequency end, making the comb stable. The repetition rate can be tied into some stable RF or microwave source, and now you know what each frequency is to a very high level of precision. A lot of labs are now doing this.
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