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OK, I’ve been posting everybody else’s YouTube videos, so what about METube? After all, it’s all about me.
Here is my YouTube debut, talking about infrared light as part of a full-length webcast on climate change. This was totally fun, I left Paul D. back at the webcast studio and ran off-stage, across the museum to the infrared heat camera exhibit…
Here’s my latest Science Teaching Tips podcast — As any teacher knows, the ability to ask good questions — and use students’ questions — is a valuable skill to have in your teaching toolbelt. In this podcast, TI staff biologist Karen Kalumuck describes how she tries not to answer every question that’s asked during a class, however tempting it may be. Instead, she’s learned how to guide her students to discover ideas for themselves.
Sorry for the lack of posts lately — I’m on the verge of porting the blog over to a new location, and holding off on posting so that I don’t have to re-post after I make the move while I’m in this limbo state. So, stay tuned for the unveiling of the new location!
For those of you in Boulder or Denver– are you interested in learning about podcasting? We’re pulling together a small group of people (mostly writers) who would like me to teach them a little bit about why to podcast, and how to go about it. The cost will be lower the more people we’ve got, and we’ll tailor the workshop (and its length) to the needs and desires of people in it. So, if you’re curious, this is a great way to dive in! Contact me at riggmail-geek (at) yahoo (dot) com.
I’ve also run some workshops for K-12 teachers on listening to, using, and making podcasts in the classroom, if anybody has an interest in that workshop.
Everybody’s favorite — microwaving a lightbulb. Pretty!
At least two posts suggest that if you put the bulb in a mug of water (with the bulb part sticking up) then it won’t explode. I believe that’s because the water acts as a dump for the microwave energy, keeping the bulb from heating up out of control.
What’s going on? This is similar physics to two of my previous posts (microwaving a CD, and the microwaving a grape post). Lightbulbs are a partial vacuum inside, but also have a small amount of gas, usually Argon. The microwave makes a current in the metal of the bulb (just because microwaves push charges around). This current lights up the filament in the light bulb. But it doesn’t glow in the way that you’re used to seeing a lightbulb glow because the high voltage creates a plasma inside the lightbulb (remember, this is an ionized gas), and the gas glows purple. I’m pretty sure that this doesn’t require the lightbulb filament — in other words, this should work with a burned out bulb.
The light pulses because the magneton that creates the microwaves in your microwave oven is pulsing on and off. I’m not quite certain why there are the different colors created, though it seems to be related somewhat to the rotation of the bulb in the microwave. It may simply be that at different angles, the lightbulb acts as a stronger or weaker antenna for the microwaves, creating more or less voltage, and thus a plasma that glows at different colors as more or less energy is dumped into it.
I never found a good comprehensive site with a succinct explanation, but this page has some interesting discussion.
This is actually what normally happens in a regular fluorescent tube light (that is, an ionized gas glows), so if you put a fluorescent tube light in the microwave, it should glow like normal.
Hey all you bio-babes (and bio-boys) out there, wanna give us some feedback? A good friend of mine is a biologist and science writer, and is starting a new blog. No, you can’t read it yet, it hasn’t begun, but she’s searching for the “killer app” of a name. She’s got some ideas, below, and I thought perhaps some readers here might have some feedback or ideas!
She says:
I want my blog to mostly be a humorous look at unusual/interesting/beautiful living organisms, but also to include biology and science in general, with a sprinkling of psychology, archaeology, linguistics and popular culture. “A blog about the weird wonderfulness of life” is my working tag line (or should it be the wonderful weirdness of life?).
Here are some title ideas. Love ’em? Hate ’em? Of course, we can’t dare to compete with the lovely simplicity of Bioephemera, but we can aspire to some lower level on the nomenclature food chain.
The Artful Amoeba (reference to “The Artful Dodger”, cleverness of amoeboid slime molds, and how beautiful they, and by extension, a lot of other organisms, are)
Angry Amoeba (.com taken, inexplicably, by a web development company)
Neon Centipede
Neon Crawling Slime
Bashful Brittlestar
The Inquiring Tentacle
Goodly Creatures (Reference to The Tempest: Miranda:”O Wonder! How many goodly creatures are there here!”)
Wild Kingdoms (.com taken — reference to Mutual of Omaha and Linean taxonomy)
Kingdoms Gone Wild
Witty Water Strider
The Well Cultured Amoeba
The Well Cultured Bacterium
Linean Explosion (from Carolus Lineaus, one of my science heroes and inventor of binomial nomenclature, and Cambrian Explosion)
Thanks in advance for any suggestions or feedback on favorites!
OK, I wouldn’t let it run quite as long as these bored college students did, but it DOES look REALLY cool (and it’s a great use of those annoying AOL CD’s, or the romantic mixes that your old boyfriend made for you):
And another really pretty one (gotta love the Darth Vader-esque breathing in the background), with an extra bonus: aluminum foil!
You can play around to see if it matters if there are images on the CD, if it looks different printed side up or shiny side up, etc. This site claims that it works best label-side up, and that the less ink on them, the less they smoke.
As you know, it’s not supposed to be good to microwave metal. That’s because the microwaves can push the electrons around in the metal. (Electrons in non-metal, or non-conductive material are kind of glued in place, so they can’t be pushed around). That can make the metal heat up (just like a metal wire will heat up when it’s conducting a current) and do all sorts of bad things to your microwave. You can read more about microwaves and what they do to metals here.
So, CD-ROM’s have a thin aluminum layer. And the microwaves push the electrons around in the aluminum, making big currents, which heat up the aluminum so much that it vaporizes (turns into steam)! The electric current is still there, though, so it jumps across the vaporized aluminum (making a pretty light show) to get to another section of aluminum. There is a little bit of similar science between this and the Microwave a Grape activity I posted earlier, in that you’re seeing air glow as electrons jump through it (a phenomenon called arcing). You’ll see a bunch of little paths burned into the aluminum after a while. An interesting observation from this site:
Some of the islands will be shaped so that they make very good microwave antennas. These spots will focus the microwave energy, and get very hot. Now you will see just a few bright spots spewing a lot of smoke. The good part of the light show is over, turn off the oven.
Here is a lovely image of a CD post-microwave, showing beautiful fractal trees where the electrical arc made its way across the aluminum.
I’m still a little confused as to why the patterns burned in the CD follow these circumferential patterns. I imagine that the CD data is originally etched in circumferential patterns, making the aluminum thinner in these regions, and thus channeling the electricity in these circles.
For extra fun, if you happen to have a Tesla Coil lying around, here is what happens when you place the microwaved CD on top of the Tesla coil. I got this from ElectricStuff.co.uk, which has even more pictures.
I believe what’s happening is that the electric current from the Tesla is flowing just through the parts of the CD that still have aluminum on it, generating high heat and arcing in lovely patterns.
In this week’s episode of Science Teaching Tips, we look at my favorite thing — light. Light, like, rulez. Dude. And so does my old mentor, Paul Doherty, who will tell you one of his best stories from the history of science about how the spectrum came to be the spectrum. I mean, what the heck is indigo anyway? The answer turns out to be, like all good history of science stories, steeped in mysticism and superstition. Give it a listen, it’s a good story!
I’m surprised at the number of people who haven’t seen this one, but then again, neither had I until I went to the Exploratorium (where they’ll stick anything in a microwave).
Put a bar of Ivory Soap (no substitutes!) on a paper towel in the middle of the microwave. Press go. About 2 minutes should do it. Here’s what happens:
And this video will show you what it looks like when you take it out afterwards
What’s going on? Well, the reason that Ivory Soap floats (try it) is that it’s puffed full of air (here’s some history of why that is). There are tons of tiny bubbles whipped into it, sort of like when you make whipped cream. It’s an emulsion of soap and air. The bubbles of air have water vapor in it. When you microwave it, that water vapor creates pressure on the air bubbles making them expand and puff up. The air bubbles themselves expand as they heat since the volume of a gas increases with temperature (Charles’ Law). And the soap softens, which allows the whole thing to expand into a big puffy pile. And when you stop heating it? The soap’s no longer soft, so it gets rigid and hard, but stays its expanded puffy self. You can use it like soap now, though it’ll be a little weird!
Other brands of soap tend to just melt.
Here’s a nice explanation, as well as how to use this as a classroom lesson on density, from Steve Spangler Science. And some more classroom suggestions from About.com.
Here’s what you do — slice a grape in half, but keep the halves connected by a little “hinge” of grape skin. Some suggest drying off the grape halves a little. Some suggest using a green grape in particular, and some say to cut it in quarters. Put the two halves next to each other, face up, in the microwave. It’s best to place it slightly off-center, as microwaves have hot-spots and “nodes” and the center is a “node” of radiation. Press go. Click here to read the rest….
I am a physicist, writer, podcaster, and educator in Boulder, CO. On this blog I get to wax on about science stuff I think is cool (like weird science, or stuff we think is true but isn't), K-16 science education, hands-on science activities, teaching pedagogy, and how to communicate science. Geek on. 8-)
Sciencegeekgirl 