Slashdot is powered by your submissions, so send in your scoop


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment Re:I freeken love this. (Score 2) 62

True - but for a homebrew quality spectrometer, using a green laser pointer can at least provide a two-point calibration (the 1064 and 532 lines - at least for cheap laser pointers with garbage IR blocking filters - You could probably get clever and determine the central lambda-max for the red and blue diode lasers but using the distance between 0th, 1st, and 2nd order diffraction spots off a grazing/dvd to get an ok value for it - but boy, these calibrations are adding up!

Comment Re:Classroom vs. Kahn (Score 1) 575

Then the problem was with the curriculum, it was with the advising that told him to take tensile mats theory for what you're describing as a 'trades' job. If they wanted to design toilets for planes, they took the wrong training approach.

Of course, if they didn't graduate high school knowing that they wanted to AutoCAD toilets, then they needed some future-proofing. They needed more broad education and training. If only there were places that taught trades, and some other places that taught a broader education with theory... Someone should get on developing that model!

Yes, what we need to change is the advising, not the education. At least, to solve the problem you focused on.

Comment Re:Might add a warning... (Score 1) 404

In the US at least, this is largely a moot point. Lasers of this power are typically used for medical technologies, and can result in health issues (as pointed out throughout the page.) For these reasons, the FDA has the authority to regulate the import of lasers - and they're not too happy with Wicked Lasers (for good reasons, imo).
I'm having a hard enough time getting a 40lb dye laser through for my research lab (missing line on some paperwork, nearly solved I hope), so the FDA _is_ checking on this stuff. Not saying that none will slip through, but as a matter of course WL's products are now sort of like powdered rhino tusk - illegal to import, pointless to pay for, and sent in hunted shipments.

Comment Re:Makes sense... (Score 5, Interesting) 410

Small nitpick - nature will optimize to a local minimum but not necessarily the global minimum. i.e. the plants might be stuck with the 'good enough' design instead of the fully optimized version. In this case, it appears that the 'natural' solution is pretty good and well optimized, especially with the low fluence case (i.e. the winter).

It's a minor but important nitpick because not all plants use the same spread and angles - I haven't read up on this, but it implies to me that there area niches in an ecosystem to have other solutions (kind of like the scavengers around the top predator - the predator might be really successful at getting it's food, but there might still be meat on the bone for the scavenger birds.) To bring the analogy back to topic, there might be other spacing/angle solutions that, alone, are worse, but with a secondary system placed interstitially, result in an overall more efficient solution. (Barely-thought about examples: placing a reflective base below, and having two-sided panels to catch other angles - or, perhaps studying the placement and angles of vine leaves can give an interstitial solution.)

So, locally minimized solutions can still be great, especially if a second-order approach cleans it up even further (as in the natural example.)

Comment Re:Nice to have the option (Score 1) 174

We professors will love to do this - once the books are ready for prime time. In most fields, they aren't. And guess who gets nuked in the Student Opinion Surveys at the end of the term for choosing a sub-par book?

Keep in mind, we evil professors (not to worry - my words, not yours - just ask my students!) have a quite full day. The only reason I'm reading Slashdot at 10:30am is because I picked up my gparents-in-law from the airport at 10pm, as decided to take a day off (been a while....) Normally, I'm either building/rebuilding/purchasing a laser, writing manuscripts, doing research, teching students in my lab to do high-quality research, prepping my own classes, preparing incoming faculty/adjuncts/instructors for the term, designing labs, writing rec letters, etc. on any given day/time (including a good chunk of weekends). I logged in 30 hours on a textbook review committee last term, trying to find the best combo of clarity, pacing, accuracy, price, and tied-in materials, and got the Dean's office to purchase a set of calculators for the class to both bring down the effective price of the class and minimize cheating. Our text is a new edition, but has the option to purchase or rent ebooks. I've got a chapter-matching sheet for those who buy the old edition.

But most importantly, I'm not special - we (essentially) all do things like this. In the end though, a few things have to come off that to-do list in order to review/write open source texts. That's a big disincentive. And there's less perceived credit/quality, so your time is looked at as misplaced (best case) or wasted (worst) by some colleagues and administrators. And others are more articulate in textbookese (a difficult language, speaking to the neonate!) that most of us, and we prefer to let them do the writing... and a host of other issues. So, it's going to take a while before open-source books are ready to go, and before we KNOW that they are. But not to worry, most of us also follow the education journals for our topics (e.g. Journal of Chemical Education), so we're aware of what's going on there, and look forward to having that to call-up. At least, those many/most of us who haven't learned the Secret Handshake of Massive Money via Textbook Writing (look it up on Wikipedia. Oh, there's no article there? Hmm, maybe I'm wrong that there's a host of money in for-profit textbook writing...........)

(My too-common disclaimer - I'm commenting on the entire thread, not just the parent-post...)

Comment Re:Bad idea (Score 1) 174

Gotta point out - you have exactly the same access to a library copy either way - but it doesn't put a copy in the student's hands in real-time while studying (except @ the library). If they use it at the library, they still don't have a copy to add to their reference shelf - they're going to the library. So, time to channel William James (I think I attributed it correctly..) : The difference that makes no difference is no difference.

It's either buy a copy to keep, or have temporary access to a copy. For the temp access, sure - a library copy is cheapest. BUT, that means it should be put on reserve by the prof. Which means, one student can spend 1-2 hours in a block with it (common lending times from lending desks). If this is a general chemistry course, as a personal example, you're looking at 96 students/section * n sections * 2 hours. Now consider inefficiencies of the queue (no one there at 8am, 10-deep lines at peak times, etc). How many copies do you need on reserve to fill the need? Who is buying them? And, is it a good plan as a student to rely on uncertainly-timed access? Inability to directly refer to the book in-the-moment for a question? Etc.?

Once again I'll probably be collectively lumped in with the 'evil professors who are part of a book-selling cabal' (yeah, right... check my bank account...), but having a dedicated copy in some form is ideal for most (YES, MOST!) courses, in whatever form the student prefers (rental, sell-back, ebook, dead tree owned, whatever.)

So, have I sold my professorial soul by saying this?
Lend me a quarter, won't you? - I'll call my accountant.
-(credit Cracker - Get Off This)

Comment Re:This was already approved (Score 1) 84

I'd be more careful than to say "scientists cannot be trusted to judge the ethical implications of their own experiments..."

This feeds a misconception that all researchers have some sort of Faustian disconnect - that we consider the ends )our research) to justify the means (including unexpecte4d consequences.) THIS is IMO the key feature of the IRB - it brings in a bunch of other perspectives to identify the unanticipated consequences and ethics of a situation. It's not a trust issue, it's a matter of perspectives. If I was setting up and experiment on tasting to determine what parts of bacon's flavor profile lends itself so well to ice cream, I might not expect some issues in taste-testing that could emerge (are the flavor compounds extracted from bacon or synthesized - and does this affect Jewish/Muslim tasters? If we disclose the bacon-source, does that undermine the efficacy of the research by 'giving the game away'? Not the perfect example, I'm sure, but not bad for waiting for the coffee to brew...)

There's nothing in your post to say you disagree (though I won't put words in your mouth), but before the "those damned evil scientists" crowd grabs hold of this one, I wanted to add these two cents.

Comment Experiments vs Technology (Score 1) 225

I've taught a course called Technology in Science Education, and my premise was that technology for the sake of technology is the wrong way to go - a sentiment I hear echoed here pretty frequently. HOWEVER, there's a reason we use technology - it gives us abilities that we don't commonly have. And this addresses that other common critique when someone wants a technology for education - it's not just a "Cool, see how this is on a computer now?" thing, or a replacement for hands-on experimentation, but rather a way to leverage more mileage vs a 1950's-style experiment. This is the way technology is used in scientific research, and a great way of thinking to instill in the kids at an early age.) I don't say, "This light bulb works great, but lets use a LASER INSTEAD! Muhahaha!" Ok, maybe I do, but that's jut me...) So, I came up with three major categories of technology that are likely to be useful in SciEd. (Not the only three, probably, and not every time - but if a tech fits in one of these bins it's worth a second look.)

1. 'Superpowers' - a technology gives us the ability to see something we couldn't otherwise see - slowing down the trajectory of a ball to measure it's x-y position in lots of time steps; using a spectrometer to separate colors (or focus on a small slice of wavelength) and find concentrations; authentic planetary models, with the ability to change the pace of time (and obviously the scale). Basically (and whimsically) think of any superhero/villain, and ask what science they could have done. Then find a technology that gives you that ability.
2. Data aggregation and representation - when the basic data (numeric or otherwise) are pulled together in one place that allows interaction, subtle connections can pop out (especially with good classroom scaffolding). My immediate go-to examples are a touch outside of science, but are at least illustrative. Simulate 1000 spins of a roulette wheel in Excel (or your favorite programming language or open source package... gotta CYA this statement since this is Slashdot...), connect it to the Martingale strategy, and show that statistics owns the day with gambling.
3. Administrative tools - self-explanatory, these help with administration of the class. Often scoffed at by people who have never taught, and aren't trying to tease out the nuance of 'what went wrong' on that exam, or when it only 'looks' like that got it. Things like choice-analysis from a multiple choice quiz for spotting persistent misconceptions, only-the-fly 'clicker' quizzes, etc.

My one strong caveat (I did say it was worth a SECOND look - which happens here) - once you identify a technology that might be of interest, the question should always be, "Is this worth it (time, money, pedagogy, etc.), and can I do the same thing low-tech?" This is where you cut out the "It's just like real life, but ONLINE!" instinct that sometimes pops up.

Even if the same thing could be done low-tech, it may still be worth adapting into high-tech - but make sure your reasons are good. Perhaps your school has a tiny science budget and the experiment would otherwise go unperformed, or if you want a quick aside or demo and can't spare the time in the lesson for the physical setup of the demo. In these cases, tech may still be the answer.

My two cents anyway!

Comment Spell out acronyms at least once!!! (Score 1) 105

ACS = ....
American Chemical Society
American Cancer Society (I immediately think of these first two because I'm a member of one and a follower of the other...)
American Constitution Society (wow, i.e. we can play Mad Libs here - American Cxxxxxx Society)
American College of Surgeons
Association of Caribbean States (hah - now I'm not an Americentric...)
American Colleges of the South
Adobe Creative Suite (would make sense in a story about piracy)
Applied/Academic/Accounting/Agile/Awesome Computer Systems (this pattern is a regular pattern mine!)
Applied Common Sense (the summary is in need of, so an unlikely match...)

Shall I continue...?

Comment Re:Black and White (Score 1) 252

I'm still concerned about the black vs white heat emission issue. The photochem and energy transport phenomena don't change on the 'outbound' side for white vs black. Perhaps the kinetics will change - but that wasn't part of the discussion before. And yes, the heat transport phenomenon will definitely be tied to the material, surface structure, etc. - I agree on those points that others have raised. But, those points are in agreement with my original point, not in opposition - the variable of concern for out 'other' category is NOT color, but material! Color becomes an issue when determining the energy in, not the energy out.

People are getting caught up on the issue of a blackbody vs whitebody. They will both emit light from the 'blackbody' process based on temperature, not color. Remember that the terms 'blackbody' and 'whitebody' are tied to thepractical experimental side that led to the fundamental measurements.. All objects will have both blackbody (emittive) and whitebody (reflective/scattering) behavior in different proportions. Perhaps I was not careful enough in setting that up in my earlier post. In the end, the albedo differences some pointed out are tied to the reflective/scattering behavior generally 'drowns' out and blackbody components. So I are that a low albedo is preferable for a 'spy' satellite (and the sort), but that has to be balanced against the light absorption heating.

So, the discussion is a tangent from the original point - the whatever-paint-body will lose a small amount of thermal energy by emission of a photon. This process will likely be slower than the rate of absorbed photons in all cases I can imagine for an orbiting body (unless perhaps it's parked in the shadow of a planetary body - then we'd need numbers for Mie scattered light around the planet, etc. But now we're really running afield.) So:
      energy out - independent of paint color
      energy in - minimized for low absorptivities (i.e. white or reflective)

So, if you're minimizing solar heating for an orbiting body, black is a poor choice. When you begin balancing this against detectability, you have a more multivariate problem. But even there, I would aim for a high reflectivity approach that is directional, and directed away from potential observers. Or (in the ideal world where we do not live) for 100% efficiency solar panels (in the realistic world, perhaps a transformation of the light into something mostly other than heat can still thread the needle. Again, tangential.)

For my money, I'm going for a surface that's highly reflective but highly directional, and I'd pont is somewhere I never expected an observer. Better yet, I'd have an umbrella (black) set up in that direction in case an observer ever was there. And, while I'm wish listing, I'll put that high efficiency solar converter at this point, to further mask the 'beam' reflected and turn it into useful power, that doesn't heat the real satellite (so we want a tether with minimal heat transfer.)

(Merry Christmas all, the outline for a DARPA grant - if it hasn't already been done.)

Comment Really?!?!?! (Score 1) 171

So, we're now jumping on the bandwagon where everything is spying? (I know, I must be new here...) Because, what _I_ read was a barebones article (193 words!!!) barely longer than the summary, that basically says they are using imaging of parking lots (and they implied traffic patterns as well) to see how full they are. I might be wrong, but my response is already almost longer than the article which makes it difficult to tell. I say it's a valid approach, spun up via alarmist phrasing to look like a privacy article.

Please, next time you flee in a panic from road surveyors who 'are there to spy on you and determine your vectors', please stay in your lane, because I'm already dealing with enough poor drivers... Deep breath - just because they have eyes pointed in your general direction that does not constitute spying.

Comment Re:Black and White (Score 0, Troll) 252

Not only would I insist that this is an incorrect statement, that isn't what your link says at all.

Black items will ABSORB more light. When light (i.e. the energy contained in a photon) is absorbed by a molecule, there are a certain number of likely fates for this energy. Remember, 'what goes up, must come down' - an excited molecule will relax through one of these processes:
  - fluorescence or phosphorescence - the light comes out a different (and lower energy) color (these differ by how long they take to occur).
  - photochemistry - they react with something or break apart while excited. Bonds are made or broken.
  - vibrational energy (i.e. HEAT) is given to surrounding molecules.

The third (heat) is by far the most likely outcome, and occurs alongside the other two EVERY TIME! In other words, because it is black it ends up with MORE heat energy. It is not radiating more heat because it's black; it is getting more heat because it's black, which as a result means more heat is given off.

AND - a black satellite will overheat much faster,which goes directly against your logic.

There are a number of different tile types that are black: gives a nice rundown.

The only way that black would help dissipate heat is that when heated up, the blackbody photons they give off would yield a minor loss of heat energy (multiple small vibrational packets of energy put together to make a light photon, if you will...)

Comment Re:Effect on Normal Eyes? Donut Vision (Score 1) 112

It sounds like this could be a treatment that (with some modification) could be used to treat folks with laser damage to their eyes (or any other damage caused by highly focused light.) In that case, the 'donut hole' would be fairly small. To some degree, I also wonder if defocusing an area that illuminates small blind spots might be advantageous - instrad of a blind spot, instead the person would have a blurry spot...

Comment Re:Freedom of speech should be a law ;) (Score 1) 631

Playing the Devil's Advocate for a moment, I do hope that people will ask themselves how they would respond to this parallel case:

A senior clerk in a court office (e.g. parking permits and citations - feel free to pick what one for yourself) has acceptable performance in the office. On the 3rd page of the newspaper, a photograph of this person at a racist rally (e.g. KKK) appears, and they are holding a sign backing these racist beliefs. Should the local government feel that their public behavior off-the-clock may impact their official civil function? The next-tier officials are concerned that patrons (remember, not all court patrons are citizens/taxpayers/etc - hence, patrons) may justifiably feel that this government-provided service may unfairly or ineptly handle their issues based on their public, non-job-related performance.
- Is this grounds for disciplinary actions?
- Should this same standard be applied re: teacher/strippers?

And for those who like to assume the question = the answer, notice that I didn't take a stand on any side, I'm just pointing out that we should either be consistent in our reasoning between these cases, or have a well thought-out reason that they should all be treated differently. Food for thought.

Slashdot Top Deals

No man is an island if he's on at least one mailing list.