Cool Science

Unexpectedly, I learned some chemistry tonite from David Blaine . Is it bad form to give away an illusionist's secrets? Hmmm. Well, I guess I'll risk it seeing as how I don't figure out most of his illusions/tricks any way and it's very interesting science.

The illusion is a great one for Blaine's street magic style; he wanders down the street until he spots some one drinking a hot beverage. That's important. He urges one of the coffee-drinker's friends to produce some coins, a whole bunch. That is also important. He plucks a nickel (interesting choice) from the palm of this unsuspecting person and places it in his own hand. Blaine then pours the other dude's coffee into his own hand onto the coin. Before everyone's eyes the coin melts and slips through Blaine's fingers.

At first, I felt outrage, feeling certain that Blaine had polluted the streets of fair NYC with mercury, lead or both. But I was wrong. I did know he could have only used an alloy with a peculiar property. And after a few moments on the 'net, I knew this could only be Field's metal, a sufficiently non-toxic alloy of bismuth, indium, and tin which has the marvelous property of being a fairly deep eutectic (by 'deep' I just mean that it is a particularly low melting alloy compared to other eutectics). So what is a eutectic alloy? It's a specific mixture of elements which forms a solid well below the melting points of any of the individual components. Of course if any one in my lab were to be caught discarding a few grams of bismuth, tin and indium in the streets I would be fired and my host institution would be fined a six figure sum. Call it 'magic' and apparently the EPA doesn't care anymore. Sigh.

Perhaps the best known eutectic alloy is solder, which epitomizes what a eutectic is all about. Solder is a eutectic metal alloy which melts low enough that we can work with it fairly easily and safely with soldering irons. Another way to look at it is that solder solidifies very quickly once the heat is removed, which is a nice feature since you don't want to risk having the solder deform while you're waiting for it to cool and solidify.

So you have surely figured out now also how this works. Back in his studo, Blaine (or an assistant?) made plaster casts of all of the silver colored coinages and then made a good stash of them all using Field's Metal, which melts at 62 Celsius and therefore is trivial to melt and pour into casts (and is also silvery in appearance). As per the above link, it's so easy to cast Field's Metal that it can be a children's toy! Since Field's Metal melts at 62 Celsius these fake coins will stay solid in Blaine's pocket with no trouble. Blaine urges the bystander to pull out a bunch of change - he needs to spot a good match to the fake coin he has stashed somewhere in his sleeve. When Blaine takes a real coin out of his victim's hand, he only needs a sleight of hand to substitute his own coin. Then pouring hot coffee (a good bet the coffee is hotter than 62 C) onto the fake Field's Metal coin, he lets everybody watch it melt in the palm of his hand and then let's the molten metal slip through his fingers for extra drama.

So 'eutectic' is a pretty scary word, but just recall Blaine's amazing melting coin as an easy mnemonic.

Posted by Dave at 11:45 PM | Permalink | Comments (3) | TrackBacks (0)

Here are a few tips which I'll feel better about after I exorcise them here. Some of these are 'official' and some are 'dave-isms'. Can you spot which are which? Enjoy:

1.
spectra : plural
spectrum : singular
spectrums : NOT A WORD

Use in a sentence: "My last spectrum fit well with the other spectra I acquired today."

2.
Tick marks in figures should never lie inside the figure body, since they aren't data.

3.
data:plural

Use in a sentence: "None of these data support the model that..."
Trick: replace 'data' with 'facts' to determine if you have written your sentence properly

4.
OK, this is not specific to science, but never begin a sentence with 'Because'.

5.
Similarly, never begin a sentence with 'This'

6.
Omit figure titles. If you *must* have one, then don't regurgitate the axis labels.

7. Incredibly, contractions are making it into publications (don't, can't, etc.) showing that some editors don't (pardon: do not) seem to care about proofing for these any more. Catch these yourself or else.

Posted by Dave at 12:22 AM | Permalink | Comments (4) | TrackBacks (0)

It's almost Father's Day and the golf cliches are building to an unimaginable high. Is it too much to ask to spread out the emphasis a little? Geek dads every where rise up, rebel, let your iphones be heard! Honestly, De Beers look like amateurs compared to the golf lobby who might just succeed in taking over Father's Day. What is the world coming to?

Of course, that's what we should be saying about this oil spill. Americans are demanding that new technologies and science be brought to bear to remediate the oil, but nobody seems to get it. BP has created a disaster it can't afford and doesn't know what to do. That's obvious. The government is in a trickier position of having to explain to Americans that seemingly miraculous solutions for soaking up oil may have more sinister problems. The government would appear to be sticking (hmmm, pun not intended but it works) to conventional approaches which have passed the myriad of regulatory hurtles to show that they make some sense and won't do more harm than good. The reason is obvious: the feds don't want to make things worse - the well known and rightly feared 'law of unintended consequences'.

And so I made the mistake of tuning into Huckabee. Sigh. I got excited when he started an episode with a basin of water in front of him and revealed a studio full of lab-coat clad people all with basins of water and oil samples ready to demonstrate new technologies to remediate oil. SCIENCE, I thought. And so I watched intently...as Huckabee proceeded to roll a previously recorded smear on Obama for several minutes. I think 'ok, I should have expected this, I'll tune back in a few minutes'. So I channel surf for 5 minutes or so, come back hoping to see some creative science and exciting ideas and...Huckabee is running another over-produced smear on Obama for many minutes. So I assume he got to it at some point, but not before over-indulging his political feelings and discouraging me of my patience.

Well dads, as at least a symbolic touch we could all go into our garages and turn in those random jugs of used motor oil we all seem to have. I just did that recently - felt good. This is where I'd really like to cook up some cool idea to use Father's Day to rally a fresh attack to stop the oil in the gulf coast. I got nothing (ok, not entirely true) - but it's not going to be that easy. As for Father's Day, let's reclaim our day : - stop the toil on the golf course.

Posted by Dave at 09:55 PM | Permalink | Comments (0) | TrackBacks (0)

This is where I confess that for some time now I have been surfing the web and youtube for information on the brown recluse spider, because now that we have kids and we live in an old house with lots of spiders I get just a little defensive and paranoid. The outcomes of a nibble are gross, and I'm not even going to link to the youtube videos, and let's just leave it at that. Now even though the brown recluse doesn't do well in our fair state, I'm allowed to be concerned.

So the other day we get in the car to drive to the PO to drop off a netflix and I notice that there's this elongated piece of debris like fine straw streaming horizontally off of the sideview mirror like a thin bunch of sticks, flapping wildly in the breeze. It's flying right next to my arm which is hanging out the window and I think about flicking it off. But then at a stop sign, out of the corner of my eye this little group of twigs unfolds in Ridley Scott fashion into a nicely sized half-dollar sized spider. And when I go again it stretches out and goes flapping in the breeze again holding on by just a thread of silk. I'm impressed and feeling both some admiration and sympathy for the arachnid, but also a little creeped out...because a big, freakishly strong spider is flying chaotically next to my arm in a 30 mph breeze. I soon draw my arm into the car.

So I pull over to take a closer look at the spider. It's light brown, with long thin legs. But so are like half of all the spiders in the world so I need to be a little more intelligent than that. First, it was big and in the right size range for an adult recluse, and out of range of the size of many common spiders. Next, it was very fast and was darting with surprising speed between the mirror and the hood when I brought a piece of paper nearby it, also classic 'recluse' behavior like the videos which stress the unusual speed and retreating reaction. Further, the body was fairly small compared to the legs, consistent with expected recluse appreance. And for what it's worth, in the very minor menagerie of spiders I've encountered so far, I hadn't seen any one like this before.

Now remember the recluse is not happy in our climate and has to be introduced from a warmer one, like the fair states of VA and NC where we had just spent time a couple days prior, and has to be somewhere warm also (like the warmth of a car - and our weather had been unusually warm the whole time also). In other words, it seemed plausible to me that this fellow could have been a stow away and enjoyed the warm spell that we were in.

So the only remaining challenge is to spot the violin (aka 'fiddle back') on a big, fast moving spider. This specimen was a lighter tan color, suggesting it might not be doing well and which is also a normal variant for the recluse also. But this does make it harder to spot the violin due to the weaker contrast, especially for a total novice. I did see darker coloration behind the head in the right area, but couldn't pin it down and had no interest in doing so.

The abdomen was the only thing that gave me doubt, as it seemed narrower than in the classic pictures which depict a rounder abdomen. But to be perfectly honest the little bugger had an appearance some what in common with this guy and the size and speed and shape were too close for comfort. So as this large, brown, agitated spider darted back and forth unpredictably around my open window with the kids strapped in nearby I flattened it unceremoniously with Jenn's flip flop.

Could have been a smart move, or could have been a dumb city guy doing in a perfectly harmless spider after watching one too many youtube videos. A candidate for something harmless and admittedly more likely would be the 'giant house spider', a nice big brown spider also. It's a strange world.

Posted by Dave at 12:10 AM | Permalink | Comments (0) | TrackBacks (0)