swansont

We have the original system out so we could play with it. The later incarnations are much more compact, as we had decided on a design. It's modular and fiber-coupled now; we have tried three different laser sources, and none of the optics had to be reworked — just plug in a different fiber. I'll post some more pics when I get back to the office.

old laser layout http://tycho.usno.navy.mil/clockdev/lasertable.jpg newer laser layout (the laser itself is in another part of the rack) http://tycho.usno.navy.mil/clockdev/Rboptics1.html

Either grade inflation, or the fact that many post-bac programs have similar standards. I went to a state school for my PhD, and a "C" was a failing grade. BFD.

Not so much the physics that's attacked on a regular basis. Gravity can be both, you know. Warped space is from a classical theory, gravitons are from a quantum approach. Epicycles were ad-hoc, and you discard them for that reason. Occam and his shaving utensils. If you see any current physics that is ad-hoc, then we'll give you a pass on the initial accuracy of the replacement. Alternatative science can be (and often is) brought up in the speculations area. Most of the time it's not even close as to whether it should be in a science section (i.e something that comes close to passing as a theory) or in speculations.

But that would be a correlation with education, not intelligence. They aren't the same thing. It was a small-sample study. There's a reasonable chance it was meaningless/wrong; the kind of test is a zero-sum game, and Pangloss has already alluded to this. But the Slate article is wanting: "participants had one-tenth of a second to look at the letter and another four-tenths of a second to hit the button. One letter, one-tenth of a second. This is "information"?" That's scientific criticism? No, it's not. It's science-bashing rhetorical crap. The whole article is full of it. Saletan is making a huge extrapolation of a relatively simple test, and adding a lot of his own interpretation to the science, from what I can tell. And I have to ask: where does the conclusion come from about the motivation for the study? The scientists saw a claim made by "political scientists and psychologists" and devised a simpler test to investigate and see if there was any weight to the claims. Is it so unreasonable to hypothesize that there might be some difference in function between people who have different world views? He doth protest too much, methinks.

There's not a unique mapping, though. Like some physics calculations (especially in thermo), answers can be path dependent — it's not just a matter of where you end up, it matters how you got there. I think units is also "path dependent" and you're focusing on the endpoint and ignoring the path, as it were. The endpoint does not contain the information about how you got there.

As I said before, there's more to the story than units. Using the example of energy and torque, it's possible to exert a torque and transfer varying amounts of energy — it all depends on how much of a rotation is involved, and angles are unitless. Dimensional analysis can tell you if an answer is wrong (the units don't work out) but can't guarantee that the answer is right.

Oh, I hope not. I don't want to go through today again.

Some unit combinations have special names and/or physical interpretation and others do not; kg-m/s are units of momentum. Others might depend on the context of how terms are defined or grouped in a formula. If you took gravitational potential energy, for example, PE = mgh, and arranged it to be PE/g = mh, you'd get units of kg-m, which would make sense if you were figuring PE for a given height on different planets (though why you'd be doing that is another question altogether) Also note that a kg-m^2/s^2 is equivalent to a unit of energy or of torque, and they are conceptually different things. Units don't tell the whole story.

No doubt in my mind that this was more true when most typists were properly trained, on QWERTY keyboards, before the advent of the personal computer and the rise of legions of us hunt-and-peck-ers.

I think the papers were written by the experimenters rather than the lab, or the experiments. You have no idea about how I type. For "stewardesses" I use my right hand on the "t" and "r"

Fermilab has created a sentient entity that can write and publish papers? Cool!

Great, you scared her off. She could've just checked out my home page for physics jokes instead of getting the physicist-as-stripper mental image. Anyway, this was emailed to me recently: Pocket Taser Stun Gun, a great gift for the wife. A guy who purchased his lovely wife a pocket Taser for their anniversary submitted this: Last weekend I saw something at Larry's Pistol & Pawn Shop that sparked my interest. The occasion was our 15th anniversary and I was looking for a little something extra for my wife Julie. What I came across was a 100,000-volt, pocket/purse-sized taser. The effects of the taser were supposed to be short lived, with no long-term adverse affect on your assailant, allowing her adequate time to retreat to safety.... WAY TOO COOL! Long story short, I bought the device and brought it home. I loaded two triple-A batteries in the darn thing and pushed the button. Nothing! I was disappointed. I learned, however, that if I pushed the button AND pressed it against a metal surface at the same time; I'd get the blue arch of electricity darting back and forth between the prongs. AWESOME!!! Unfortunately, I have yet to explain to Julie what that burn spot is on the face of her microwave. Okay, so I was home alone with this new toy, thinking to myself that it couldn't be all that bad with only two triple-A batteries, right ? !! There I sat in my recliner, my cat Gracie looking on intently (trusting little soul) while I was reading the directions and thinking that I really needed to try this thing out on a flesh & blood moving target. I must admit I thought about zapping Gracie (for a fraction of a second) and thought better of it. She is such a sweet cat. But, if I was going to give this thing to my wife to protect herself against a mugger, I did want some assurance that it would work as advertised. Am I wrong? So, there I sat in a pair of shorts and a tank top with my reading glasses perched delicately on the bridge of my nose, directions in one hand, and taser in another. The directions said that a one-second burst would shock and disorient your assailant; a two-second burst was supposed to cause muscle spasms and a major loss of bodily control; a three-second burst would purportedly make your assailant flop on the ground like a fish out of water. Any burst longer than three seconds would be wasting the batteries. All the while I'm looking at this little device measuring about 5" long, less than 3/4 inch in circumference; pretty cute really and loaded with two itsy, bitsy triple-A batteries) thinking to myself, "no possible way!" What happened next is almost beyond description, but I'll do my best... I'm sitting there alone, Gracie looking on with her head cocked to one side as to say, "don't do it master," reasoning that a one-second burst from such a tiny little ole thing couldn't hurt all that bad.. I decided to give myself a one-second burst just for heck of it. I touched the prongs to my naked thigh, pushed the button, and ......... HOLY MOTHER OF GOD, WEAPONS OF MASS DESTRUCTION!!! I'm pretty sure Jessie Ventura ran in through the side door, picked me up in the recliner, then body slammed us both on the carpet, over and over and over again. I vaguely recall waking up on my side in the fetal position, with tears in my eyes, body soaking wet, both nipples on fire, testicles nowhere to be found, with my left arm tucked under my body in the oddest position, and tingling in my legs. The cat was standing over me making meowing sounds I had never heard before, licking my face, undoubtedly thinking to herself, "Do it again, do it again!" Note: If you ever feel compelled to "mug" yourself with a taser, one note of caution: there is no such thing as a one-second burst when you zap yourself. You will not let go of that thing until it is dislodged from your hand by a violent thrashing about on the floor. A three-second burst would be considered conservative. SON-OF-A-... That hurt like hell!!! A minute or so later (I can't be sure, as time was a relative thing at that point), collected my wits (what little I had left), sat up and surveyed the landscape. My bent reading glasses were on the mantel of the fireplace. How did they get up there??? My triceps, right thigh and both nipples were still twitching. My face felt like it had been shot up with Novocain,and my bottom lip weighed 88 lbs. I'm still looking for my testicles? I'm offering a significant reward for their safe return. Still in shock. P.S. My wife loved the gift, and now regularly threatens me with it!

Ran across this http://arxiv.org/help/endorsement.html "During the submission process, we may require authors who are submitting papers to an archive or subject class for the first time to get an endorsement from another arXiv author."

I think Gregor Mendel would disagree with that statement.

Recent discussion has been moved here: http://www.scienceforums.net/forum/showthread.php?t=25902

No, she likes Missus, but not Mrs

It makes you turn into Johnny Carson? Cite please, for the carcinogenic effects of heated olive oil.

Not if it's made of depleted uranium

Mrs. Tilly likes to be spooked but not to be scared. Mrs. Tilly wants to be good but not great. Mrs. Tilly likes to be aberrant but not abnormal.

A doctor is examining a teenage girl. He grabs his stethoscope and says to her, "Big breaths." She replies, "Yeth, and I'm only thixthteen."

Found a nice post of things to keep in mind for anyone thinking they've overturned modern science. Some old, some new. http://insti.physics.sunysb.edu/~siegel/quack.html

Found a nice post of things to keep in mind for anyone thinking they've overturned modern science. Some old, some new. http://insti.physics.sunysb.edu/~siegel/quack.html

I wouldn't use "Family Guy" as a technical reference. Carbon has a higher melting point. Tungsten has the highest boiling point.

The point of the HW forum is not to do the problem for the poster, but to help him/her solve the problem and learn how to do it.