High-resolution improvised lightbulb spectra

Here’s a high-resolution 2nd order spectra of one of our high-tech fluorescent spotlights. Note the green doublet.


So, a few scientists were questioning the details of my methods and reproducibility of my spectra, so here are some more details, and tips to get better resolution.

Firstly, the “line” is actually a monochromatic image of the light source, so masking the source with a slit will narrow the bands.


The following picture with low zoom shows the camera, light source, and 1st order diffraction spectra all reflected in the CD- this is the same source in the picture above.


I didn’t have quite as much luck with these old-fashioned tube fluoros:


But still got this first-order spectra:


A fancy-pants new “warm” compact gave me the following first order spectra. The ceilings of the second 2 rooms were too bright to get nice second order spectra.


So what did y’all do with your Friday night?

Empirical nature observation of the week

Unlike a bee, a single wasp can sting more than once.



Methodology:
While riding home with neck of cycling jersey unzipped for airflow, lodge a wasp between skin and lycra shirt. Count the number of stings. If greater than one, hypothesis is consistent with data.

BTW, this particular wasp was also way more painful, per sting, than a bee. Bee stings generally bother me for half an hour. This burned for days. I’m not sure how repeatable this experiment is, though. It is the second most unlikely bike mishap I’ve ever had.

Lightbulb spectra on the cheap

There’s been some talk around the blogosphere about the new lightbulb proposal for Australia. I must admit that I’ve been a compact fluoro nut since the late 80’s, when I bought a 30 dollar lightbulb out of a Greenpeace catalog for Christmas.

There’s tons of theory about lightbulbs that I’m sure smart bloggers would love to spend hours talking about. Some of the explanatory physics can be found here. But despite the numerous off-topic rants that I post, this blog is allegedly about analytical techniques. So instead of pontificating, I’ll just show my spectra.

In order to get a spectra, you need a spectrometer- any device that is capable of breaking down light into its component wavelengths. Most households have dozens of potential spectrometers lying around, for most of the indoor spectra shown here, I used U2 (see figure).


For the streetlights, I used a crappy old Indigo Girls CD that I haven’t touched since I stopped asking lesbians out about a decade ago. I recommend something similarly expendable for outdoor use. If you’ve put all your music on an iPod and chucked all your CD’s, bad luck.

So, below is the spectrum of an incandescent light bulb, generated by reflecting the light off of a compact disk at an appropriate angle, and photographed with a digital camera equipped with a macro setting:


Note the relatively dim blue and the continuous color all the way through the rainbow.

A cheapo Phillips compact fluoro follows:


As you can see, the light is broken up into discrete color bands, with gaps in between. Note also that there is a fairly strong violet emission, a region where the incandescent was fairly weak.

Here is a modern Nelson compact fluoro, of the “cool white” variety:


Note the gaps between the violet, blue, and green have been partially filled, but that the spectra is still not smooth.

Streetlights have spectra too. Here is an orange light- probably a high pressure sodium lamp.



And here is a bluish streetlight.


I tried doing some stars as well, but even with Sirius almost directly overhead, I couldn’t get enough light to get any colors using this method.

How this all relates to energy efficiency is a whole different story, but the point is that anyone with an old U2 CD lying around can determine what sort of light is given off by various sources. So baby, baby, baby, light my way- and I’ll tell you what colors it contains.

Childbirth and canyons

Ms. Lemming and I spent the weekend at a Calm Birth workshop, which I am still trying to get my head around. The basic premise of the thing seemed simple to the point of being stark raving mad. So I’m kinda thinking it through on the keyboard right now. Pardon the rambling, but I’m a fairly unempathetic guy trying to a) get my head around childbirth, b) get my head around this alternate theory, and c) evaluate the two hypotheses based on data that I can never hope to acquire. So expect the most unconstrained armwaves and absurd assumptions this side of astrobiology.

The basic point of the calm birth people was that the uterus is a very large muscle with a job to do. Like all muscles, it gets distressed it if doesn’t get all the oxygen and nutrients it needs. And that hurts. Trouble is, there’s a catch. Fear and pain both tend to trigger a fight or flight mechanism, in which the blood is directed away from the internal organs and into the arms and legs. While great for fighting hyenas and running away from crocodiles, redirecting the blood supply to the limbs actually decreases the supply to the uterus. This causes more pain, which releases more adrenalin, in what can most charitably be called positive feedback, where “positive” means excruciating.

The corollary is that if pain and fear can be avoided, then birth will be pain-free, allowing the mother to enjoy what should be a special moment. So the aim of the weekend was to give us all the tools to deprogram the modern, painful birth expectation.

Sounds like typical theoretician gobbledygook, doesn’t it? To their credit, they never said it would be easy to do, and most of the weekend was focused on practical techniques and methods to deal. And since we still have a few months until the little laccolith extrudes onto the surface, there is plenty of time to learn and practice.

Of course, since I’m lousy at actually thinking about giving birth, I’ll try a metaphor instead. And since all bloke metaphors for childbirth are necessarily flawed, I’ll just pick a lousy one that gives me an excuse to post pretty pictures.

So. Childbirth is not that different to hiking into the Grand Canyon and back. Even a quick trip takes most of the day, and a long one can take several. If you’re unlucky or ill-prepared, you can die, and in any case, the trip will be tiring.


Sure, there are a few minor differences. Instead of meeting a brand new person at the end, you’re more likely to find a mule. Park rangers and midwives sometimes have minor personality differences. It isn’t your feet that get torn up in childbirth. And the bridge isn’t held up with cables.


But there is another angle to this comparison that’s worth considering. Prior to the late 19th century, the wilderness was regarded with open terror, at least by white folks. It was an empty, unforgiving desolation, where ravens and condors would gladly feed on the carcasses of anyone foolish enough to venture into the backcountry.


Back when the Grand Canyon was first explored, hiking into or out of the Grand Canyon was a desperate measure only done if fleeing Indians, rustling cattle, or escaping a boating mishap. The idea of enjoying a hike, or having a transcendental walking experience was beyond their comprehension. So maybe a positive birthing experience isn’t so mad after all.

If nineteenth century naturalists were able to change the cultural perceptions of wilderness, what is stopping the next Joan Muir from doing the same to childbirth?

In any case, Mrs. Lemming is way calmer and more positive, so even if I can’t get my head around this thing, the boost to her confidence should make it well worth the time and money.

Richard Dawkins’ ideological dark energy

In his post Thank You, Richard Dawkins, Sean Carroll posits that Richard Dawkins has made the universe more hospitable for Atheists by moving the Overton window in a direction more amenable to his point of view. More problematically, he suggests that this makes up for Dawkins’ abrasiveness and divisive approach. Because Sean’s a physicist, I’ll use a cosmological metaphor to illustrate why I disagree.

Below (fig 1) is a simplified two-dimensional ideological universe, With the axes Idea X and Idea Y. The ten inhabitants of this universe are represented by different colored ellipses, plotted according to each person’s belief in ideas X and Y. The size of each ellipse shows the degree to which each person’s ideological position varies- think of it as a tolerance, or uncertainty value.



The problem with divisive, extremist positioning such as that done by Dawkins is that it accelerates his followers along the axis he promotes, but it does so while leaving the inhabitants of that universe with constant (or even decreasing) uncertainty/tolerance. Extremism is the dark energy of the ideological universe, which accelerates its outliers away from the gravitational tug of consensus.



As is shown in figure 2, extremist expansion spreads the same summed individual tolerances over a larger area, reducing the overlap. In contrast, expanding the universe by simply increasing the tolerance of the individuals who inhabit it increases both cohesion and range (figure 3).




If we think of the Overton window as the mean +/- 1 sigma of the population for any given idea, then extremism does move the window. But by decreasing the overlap, it reduces the probability that a solution in this window will fit all the data.

Fortunately, there is a counteracting force to extremist dark energy. Richard Nixon’s great silent majority is the “dark matter” of this universe. In figure 4 (below) the plotting of this large, but often un-noticed population of centrist, tolerant people gives this universe the additional mass and connectivity to remain cohesive. But sociologists have not yet told us what the necessary ratio of dark matter to dark energy is in order to prevent an ideological universe from exploding into irreconcilable pieces in the way that the physical universe is doing.



In the early stages of cosmology, researchers didn’t know the relative proportions of dark matter and energy, so many of them simply assumed that they must be fairly similar. By the time anyone got around to measuring them, it was billions of years too late to do anything about it, and the universe was already accelerating into infinity.

In ideology, as in space, the ability to act on a nearby body is inversely proportional to its distance. We can’t do anything about the extremists blasting off of the other side of the universe. But we can hope to slow the ones who fly through our ideological space. And it is vital that we do this. Because by encouraging dark energy, we risk dying an ideological heat death, frozen into diverging paradigms in a universe devoid of light.

Cool-aid, creationism, and the communist threat

A number of the internet’s shriller McCarthyist scaremongers have been getting their knickers in a twist over the recent New York Times article describing the paleontologist Marcus Ross. Dr. Ross has landed himself on the fanatical secularists’ blacklist for “using his secular credentials for promoting global communism witchcraft dangerous creationist ideologies and opposing the teaching of evolution in schools.

Exactly how has he done this? At the risk of attracting the fire of the witchhunters myself, let me suggest a blasphemous methodology. Let’s look at the evidence.

Dr. Ross is a self-proclaimed young Earth creationist.
Dr. Ross has had a life-long love of Mesozoic macrofauna.
Dr. Ross recently completed a PhD in paleontology at the University of Rhode Island, defended without mention or use of fringe religiously-based theories.
His advisor described his work as impeccable.
Another professor in his department has defended his science as “good. Great science.”
Dr. Ross has taken his PhD to Liberty University, a very conservative southern Christian school, where he teaches geology from a standard (secular) science text.
While a PhD student, Marcus Ross allegedly argued that a creationist approach might be applicable to some geologic events, like the Cambrian explosion. The details of his argument are not discussed.
There is no evidence presented (not even hearsay or evidence produced by torture) that declares Dr. Ross plans to use his new degree to confoundthe masses and achieve world domination.

I say, shoot the fucker.

But before you do, please try this simple test:

1. Get yourself hired as an adjunct to teach intro geology at your local Christian college.
2. Convince the deans there to let you use a standard textbook.
3. Go into the class with a holier-than-thou, smart-ass attitude and the same standard text book that Dr. Ross uses for his class.
4. In the same classroom time, impart a greater appreciation for, and a broader understanding of geology than Dr. Ross is able to do. After all, if we’re gonna lynch this guy, we’d better at least appropriate his faculty position while he’s kicking at the breeze.

I’ve got a six-pack of Boags that says anyone who reads this blog would fail this test. Abysmally.

Of course, the main charge against Dr. Ross is that, despite the complete lack of evidence, he is somehow going to undermine the teaching of evolution in schools. But it seems to me that his career is the best possible justification for the separation of evolution and religion. Consider:

-By keeping his science free of creationist ideas, Dr. Ross has produced professional level research.
-Working in this field for the better part of a decade does not seem to have had an adverse effect on his faith.

So, even devout creationists can benefit from keeping their religion and science distinct, and doing so does not necessarily have a deleterious effect on their religious beliefs.

Now, don’t get me wrong, I think young Earth ideas are bizarre. I’m currently paying off my mortgage by determining how many billions of years old various minerals are. To me a young earth hypothesis means an Earth that is 4.530 billion years old instead of 4.567 billion. But if this guy can compartmentalize his beliefs and working hypotheses well enough to do good science, more power to him. Evidently, some folks disagree.

Inquisitor Eugenie Scott from the National Center for Science Education says that grad schools were entitled to reject non-mainstream students, as they “would require so much remedial instruction it would not be worth my time.”

I wonder if she says the same thing about the visually impaired? In any case, none of the people who actually advised Dr. Ross have mentioned remedial education, so I think that Ms. Scott is practicing good science, by making statements that are easily falsifiable.

Professor Michael Dini from Texas Tech (where do they find these morons?) is even more disdainful, having previously refused to write letters of recommendation for students who would not renounce communism and drink cool-aid on the stand. He was later quoted as saying that scientists “ought to make certain the people they are conferring advanced degrees on understand the philosophy of science and are indeed philosophers of science. That’s what Ph.D. stands for.”

Here’s a bit of scientific philosophy for you, partner:
“Belief” is not a scientifically meaningful measure of confidence.

In fact, from what I’ve seen of professional scientists, getting emotionally attached to a theory- believing, as it were- is a greater threat to scientific productivity than treating science dispassionately. And who could be more dispassionate than a believer in an unscientific religion?

RIP Jim Luhr

Jim was the director of the Mineral Sciences division when I did my post-doc at the Smithsonian in 2002. After four years in a small inland Australian city, post-9/11 Washington was a very strange place indeed. It was a city motivated by fear and righteousness; the comfortable and relaxed mantra of the Australian Prime Minister was in all senses on the other side of the world. I remember riding my bike home from work to my grandfather’s house one day. Riding through NW Washington, it suddenly dawned on my that all the traffic had disappeared. There were no cars going either way, and I suddenly noticed that there were police and soldiers at every intersection. Nobody ever hailed me, or asked me to leave- it was just so eerie that I turned off a side street all on my own.

As a result of the Anthrax attacks, the entire US government mail was getting sterilized with 2 MeV electron radiation. For the museum, that meant that researcher’s precious photographic slides, fragile samples, and floppy diskettes were coming into the mailbox completely destroyed.

And just to make matters really disturbing, in October a Jihadist wannabe and his teenage hanger-on decided to terrorize the entire metropolitan area by randomly shooting total strangers in parking lots in DC, Maryland, and Virginia.

Amidst this metropolis of madness, Jim was the epitome of calm. As the lunatics running the world’s only superpower fulminated and blustered, he would come to work in sandals and Hawaiian shirt, relaxed as a craton. We didn’t interact much scientifically, but when he did ask about my project, it was with keen and curious questions, whose only purpose was to clarify our knowledge of the problem. He was a kind man and an inquisitive scientist. The world will miss him.

The following obituaries are available online:
The Smithsonian Institution
The Washington Post
His friends

In addition, there is a college fund for his children.

I apologize for the lateness of this posting.

The Malcolm Turnbull / Peter Garrett climate change debate

Mrs. Lemming, some friends, and I ended up watching the debate last night between the Environment Minister, Malcolm Turnbull, and the opposition spokesman, Peter Garrett, on the ABC last night. The topic was global warming, and what the government is, or should be doing about it.

The transcript is available here. My thoughts follow:

Turnbull started out extremely poorly. Asked before the debate started about the ongoing Murray-Darling water conference, he prattled for several minutes while saying almost nothing of substance.

Later, when rebutting Garrett, he tried putting words in Garrett’s mouth, by claiming that Garrett made several anti-growth statements in 1987. I don’t know what intention of this was, but the effect was very counterproductive. Firstly, it reminded us all that in 1987, Garrett was a hugely popular rack star. Secondly, it gave the impression that Turnbull was a nitpicking whinger, who preferred trivia about the past to answers about the future.

In contrast, Garrett was focused, comprehensible, and on-message. He clearly and consistently made the case that the Government was either unwilling or unable to understand the issue, much less address it, and that Australia had squandered its renewable talent and technology as a result.

Towards the end, though, the tables turned. When asked why China was outproducing Australia with wind power, Turnbull gave a very plausible and intelligent answer describing the differences in electricity distribution networks between the two countries. In contrast to his earlier evasions and personal attacks, this gave the impression that at least on some of the technical issues, he did actually understand and appreciate relevant details and complexities.

In contrast, Garrett started wandering towards the end of the debate, talking about American politics, writers, and other non-core issues only marginally related to the effect of climate change on Australians and what the government can and should do to address it.

Both of them missed chances to hammer home their points and expose each other’s flaws, but they still put on respectable performances for people only recently promoted to the front bench.

Gas pressures and tipping points

There’s been a lot of hoopla about the recent IPCC report recently. The main effect of this report is that journalists and politicians now know just how boring climate research actually is, so I’ll talk about more interesting gas-based tipping points.

For example, this afternoon on my ride home from work, I discovered the tipping point created by a gradual decrease in the air pressure of the front tyre of a bicycle. As the gas pressure decreases, the tyre footprint on the ground expands, and this gradually increases the traction- until the tipping point. Past that, the tyre collapses, the grip disappears, and the bicycle ‘flips’ to a new metastable state with lower gravitational potential energy. This is shortly followed by the frictional dissipation of any kinetic energy, which was quite substantial this afternoon.

But the real stinker is that I seem to instinctively land in the same position every time I go down- whether falling off a bike or motorcycle, whether turning left or right, at speeds from ten to eighty kph. So I won’t even get any cool new scars from this stack- I’ve just worn the same old ones off again. Although I did manage to write and worm enough to get red welts all over by right side, so the impact points only bled a little. Still, I might take the bus tomorrow.

What do scientists actually DO?

I realize that there are only about 3 non-scientists who actually read this blog. On the off chance than more of you wander by and wonder, “What do these boffins do all day?”, here is my statistically insignificant answer.

Job title: Technical officer
Institution: Research School of Earth Science, Australian National University

My day on Thursday, February 2, 2007:

7:30 Lock up bicycle. Drop bag in office, head to ICP-MS lab, turn on laser, check pumps and chillers, and fill cold trap with liquid N₂.

7:40 Clean ablation cell and tubing, mount tuning glasses, clean and change cones, fire up ICP.

8:15 Take spare electrostatic lenses out of drying oven (cleaned on Wednesday).

8:20-8:40 get changed into work clothes, check email.

8:40-9:00 Tune laser ICPMS.

9:00-10:30 Talk to user (a petrology professor), load sample, discuss analysis, edit analytical method, do some test analyses, refine method, get routine analysis underway.

10:30-10:50 Reassemble spare ICP-MS lenses.

10:50-11:00 Update SHRIMP sample documentation.

11:00-11:20 School forum. Monthly meeting in which the director and/or business manager tell the entire staff what slings and arrows of outrageous fortune the university administration has chosen for us to endure.

11:20-12:30 SHRIMP sample preparation. Mostly polishing, labeling, and cleaning mounts made earlier in the week.

12:30-1:30 Lunch.

1:30-3:15 More sample preparation. See ¹⁴C guru in hall, discuss possible participation in upcoming mass spectrometry workshop. Liaise with rock crushing lab supervisor about a number of samples in various states of preparation.

3:15-3:45 Work on Astrophysical Journal comment.

3:45-4:00 Find papers needed for comment, email files home to self, get changed, ride home.

For those nose-to-the-grindstone students and academics wondering why I piss off so early, the answer is that the Union got cheesed off at me for working extra hours, and the university didn’t want to pay me overtime, so I stopped.

What is your day like? Anyone- even the grad students- are welcome to memify this question, but the people about whom I am particularly curious are:
CJ
Sabine (who can hopefully talk about her old job now)
James