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Monthly Archives: August 2011
Just One More Thing You Can Do With Lasers
Firing laser beams into the sky could make it rain, say scientists
While nothing can produce a downpour from dry air, the technique, called laser-assisted water condensation, might allow some control over where and when rain falls if the atmosphere is sufficiently humid.
One, Two, Three, Draw!
Drawing ‘integral’ to science learning
“From the notebooks of Faraday and Maxwell to current professional practices of chemists, scientists imagine new relations, test ideas, and elaborate knowledge through visual representations. However, in the science classroom, learners mainly focus on interpreting others’ visualisations.”
and
The press release is vague — in physics drawing free-body diagrams is generally taught. That’s an abstraction, though. Maybe they mean something else.
Compressed Again
I combined everyday soap bubbles with exotic ferrofluid liquid to create an eerie tale, using macro lenses and time lapse techniques. Black ferrofluid and dye race through bubble structures, drawn through by the invisible forces of capillary action and magnetism.
Walking on Air
Schriever plans to float-in new master clock system
I don’t always get to talk about details of work, but when it’s been cleared by someone in public affairs, then it’s “out there” and I get to link to it. This is an article about the backup clock facility in Colorado (also the GPS headquarters), which will be taking delivery of its first fountain clock in the near future. There’s a picture that explains how the fountain works that I drew up some time ago (and was improved upon by local peer review)
Though the newer fountain clock provides a stable signal, the equipment itself is very fragile.
“In order to get the Rubidium Fountain Clock into the master clock room at Schriever, the clock has to be floated, like a hovercraft, on a series of plastic mats until it reaches its destination,” Mr. Skinner said. “That prevents the bumping or jarring that might damage the equipment. Since it’s built in-house (at USNO) it would be hard to fix. You can’t just open a catalogue and order a new part.”
The “hovercraft” is, of course, the air sled I demoed a while back.
Great Chocolate Balloon Bowls!
No, that’s not an expression of surprise. It’s pudding cups in bowls made from chocolate, shaped by dipping balloons into it and letting it harden.
Wait For It…
It may have happened already, but if not, it’s just a matter of time before some jackass complains about how Irene was overhyped* because the damage/devastation was not as bad as it was feared. Which completely ignores that getting people to properly prepare is a huge part of minimizing the damage.
*I know Ron Paul has called for the elimination of FEMA, but that’s pre-existing jackassitude.
You Break it, You Bought it
Violating relativity by breaking equivalence
It’s fairly well-known that general relativity and quantum mechanics don’t get along, so the mock surprise that this happens is a little tedious, but that’s the state of (science) journalism. Once you get beyond that, it’s pretty neat.
Numerous experiments, measuring all types of phenomena, have proven that the equivalence principle holds. However, a new thought experiment published in a recent version of Physical Review Letters demonstrates that, depending on how you measure temperature, a scientist in the sealed laboratory could tell where she is. On the surface, this result would seem to suggest that the equivalence principle it not valid under all conditions, but there is a wrinkle—the researchers here suggest making a local quantum mechanical measurement. The fact that quantum mechanics is an inherently non-local phenomenon may provide a way of cheating the prerequisites that Einstein put on his equivalence principle.
One caveat here is that this is still a thought experiment, and it’s still possible that someone else will come along and show that it’s not a problem. One needs to recognize that papers are a way that scientists “think out loud” and get feedback. No doubt that this idea went through discussions and then peer-review, which are steps that should weed out obvious loopholes and problems, but when you’re at the edge of GR and QM there might be more subtle concepts lurking.
One thing to note in the article is the ambiguity/error they have presented in explaining GR
Einstein proposed the equivalence principle in 1907, a full nine years before his publication of general relativity. The idea, however, guided the development of general relativity. When combined with Einstein’s theory of special relativity, it gave rise to the prediction that clocks will run at different speeds in gravitational fields with differing strengths, and that light would be bent by gravitational fields.
If strength means the acceleration (or force), and that’s usually what is meant, then this is wrong. Time dilation depends on the gravitational potential, which is the depth of the potential well. The acceleration is the slope of the side of the well. It’s possible to be very deep in a well and have a large amount of time dilation while having a local value for g that is small.
Get Short(y)
How Long Should You Make that Youtube Video?
Data to support the hypothesis that shorter videos get more views. From my own sampling, I’d say a lot of youtubers don’t know how to edit video; all too often the “good part” is well into the video, and the boring set-up is often much longer than it needs to be.
Do You Believe in Rock 'n Roll?
Yes, we label many of the drawers in the lab. Things get lost for too long otherwise. It’s not like school, where the grad students are always there and can tell you what happened to the special wrench for tightening the marzul vanes or the tremmy pipe in the turboencabulator. (I’ve also taken to labeling many of our unique belongings, so one can put it back in a consistent location when finished with it. Assuming one actually puts it away. I’m looking at you, everyone. And me.)
This was a colleague and no, he did not screw up the spelling. The drawer contains audio cassettes for the boom box. (Kids: ask your parents, or go to Google)