I’m experimenting with the blog theme, so do not be alarmed if things look confusing, wrong, or are in strange places. Hopefully all will be settled down soon.
We were halfway down the hill when someone expressed the feeling that this area was creepy at night, and they felt like there might be serial killers or possibly zombies around.
Someone else reminded her* that if there were, she didn’t have to be the fastest–she just had to outrun the slowest person in the group.
“That would be me,” I said. It was funny because it was true.
I’m not Jackie Joyner-Kersee by a long shot, but I can generally summon some speed if necessary. At the moment, though, I was a semi-mobile traffic impediment, as I’d been limping for a day and a half for causes unknown.
Well, the proximate cause was known: the feeling that some was hammering a nail into my right knee, especially when going down stairs.** The ultimate cause was unknown: I hadn’t run into, tripped on, twisted, fallen into, bumped, or slept weirdly on anything. I hadn’t accidentally kicked myself in the knee. I hadn’t banged it on the seat in front of me in the airplane or run into the turnstile in the Tube. I had just walked around London and then started to be aware of an ‘ow,’ which quickly escalated.
Basically, my only hope lay in my lopsided gait convincing the zombies I was actually one of them so they’d go after the second-slowest instead. If it was serial killers, I was out of luck.
Human knees are interesting. Other apes have different knee joint angles–that is, their femur comes straight down from the hip, and the tibia and fibula come straight down from the femur.
For a quadruped, this is great. The center of mass is located in the torso, and between the front and back limbs it’s easily supported by two or more limbs at any given time.
For a biped, this is terrible. The center of mass is located in the torso, and when walking it’s unavoidably supported by only one leg sometimes. Stand with your feet directly under each side of your hips and then walk without moving your legs any further under your body.
If you had straight knees like a gorilla, that’s what you’d be dealing with whenever you were attempting to be bipedal. Walking’s doable, but wouldn’t walking bipedally be more effective if your supporting limb was in a centered location under your center of mass?
Enter the human knee. Your femur doesn’t go straight down: it angles inward under your body. Then your tibia and fibula go perpendicular to the ground. Your knee is the point where the angle in your leg changes:
(pictures from here)
Of course, that doesn’t mean we can all be Shawn Johnson:
But it does help with the walking on two legs.
This is how your knees, being the knees of a bipedal primate, are different from other ape’s knees. Isn’t evolution awesome? Yes.
Adaptation of the knee joint doesn’t address the “just one supporting leg while walking” issue, so there’s still the option to fall down a lot more than if we were quadrupeds.
So if there’s all these chances to fall down, why bipedalism?
Open questions in science: also awesome.
*Possibly him, but statistically it was probably her.
**So many stairs.
Welcome to the first installment of a new feature in which I will talk about different places and their roles in the history of science! Because not only does science happen every day, but many people walk around on where science happened previously every day.
Where: Arthur’s Seat, Edinburgh, Scotland
Why did I choose Arthur’s Seat? Because it inspired this feature. A friend of mine visited Scotland, posted a picture of Arthur’s Seat on facebook, and I got super excited and wrote a comment about it. I have visited Arthur’s Seat in a science-learning context.* And it was awesome. And I’m going to share with you now.
Isn’t it weird to think about when there wasn’t really science as we know it today? All someone has to do to convince me I want to read a history of science book is allude to it being set in the vicinity of the 1800s, back when science-as-we-know-it was only half-formed and it was possible to be on the cutting edge of lots of things at the same time. It completely fascinates me.
In the late 1700s, there wasn’t geology as a science. There was Arthur’s Seat, and there was a Scottish guy named James Hutton, and they were both around Edinburgh.
Arthur’s Seat is an extinct volcano. Trying to imagine Scotland with active volcanoes kind of breaks my brain, but that’s history for you.**
This is Arthur’s Seat:
And what James Hutton noticed was this: rock layers did not always nicely lie on top of each other. Sometimes rock layers had been turned vertically and there were other horizontal rock layers on top of it, and sometimes rock looked like it had flowed through other kinds of rock like a liquid.
And one of the places his noticing happened was here: the Salisbury Crags near Arthur’s Seat.
If that had happened
if the processes of rock formation moved at the same rate then that they did now***
it had taken a loooong time for those rocks to form. Much longer than 6000 years.
James Hutton was not a snappy writer. He tended to come up with sentences like this:
Time, which measures every thing in our idea, and is often deficient to our schemes, is to nature endless and as nothing; it cannot limit that by which alone it had existence; and, as the natural course of time, which to us seems infinite, cannot be bounded by any operation that may have an end, the progress of things upon this globe, that is, the course of nature, cannot be limited by time, which must proceed in a continual succession.
His book about his ideas eventually expanded to around 1200 pages, which didn’t help him at all on the publicity front, but nevertheless James Hutton was the guy who founded modern geology.
Hutton did conclude Chapter 1 of The Theory of the Earth with the following:
The result, therefore, of this physical inquiry is, that we find no vestige of a beginning,—no prospect of an end.
Okay. One, I love this quote to pieces. Two, yes indeed that is the title of this post. And no, I have not broken the song-lyrics post-titling convention:
(Fair warning: I’m going to talk about another James Hutton-related site at some point. Yay geology!)
*You’re going to encounter this class when I talk about different places a lot.
**For instance, Madison used to be covered by a glacier, but the amount of time I spent this summer hiding in air-conditioned coffee shops from 100+ degree heat indexes was regrettably large.
***this idea came to be called uniformitarianism, and was popularized by the later and better-known geologist Charles Lyell.
This post is not about dancing.
This video is about dancing (and awesomeness):
but this post is not.
No! It is to point you toward a review I did earlier this month over at the book blog Sophisticated Dorkiness, which belongs to my friend Kim Ukura. Kim is the new editor of the Morris Sun Tribune (yay, Kim!).
Here’s basically what I thought when I saw Feathers sitting on Kim’s bookshelf:
Feathers!!!!! They are awesome!
Here’s an exchange I’ve had several times since taking the book:
Me: I’m [about to read/reading/just finished with] a new book.
Other Person: What’s it called?
Other Person: What’s it about?
Me: Feathers. Actual feathers.
Other Person: …Oh.
That’s right: this book is called Feathers and it’s about actual feathers like are on birds.
To tie in to the everyday theme of this blog, reading this book has made me extremely alert to the presence of feathers. And birds.
Guys, there are a lot of birds in downtown Madison.
Here are some birds I saw while out for a walk the other day at my new, non-downtown apartment:
I promise that there are three sandhill cranes in that photo, sort of at the center and then going right.
The author of Feathers, Thor Hanson, talked about how writing a book about feathers meant that people brought him all kinds of feathers. And birds. And bird parts.
Some of you might know about it being almost always illegal to possess eagle feathers in the US. The same is true for other birds of prey.
Also, it does not require intent for you to run afoul* of this law. Just FYI.
*I definitely typed “afowl” first and almost left it.
a real, if paraphrased, exchange on the subject of swimming after eating:
[friend's boyfriend]: …and then you’re full so you sink like a brontosaurus.
me: Current models have brontosauruses with a system of internal air sacs like birds, so you’d probably float less efficiently than a brontosaurus. Because you’re a mammal, so you… don’t have the… um, air.
It’s like a disease. I can’t stop myself.
I’m also the type of person where my friends pretty much know that all they have to do to get me to like an item is to slap a Steelers logo or a dinosaur on it.*
And so it is this frame of mind which, in the course of things, brought the following article to my attention a couple years ago: Tipsy Punters: sauropod dinosaur pneumaticity, buoyancy, and aquatic habits.
You know you can’t resist that title.
Brontosauruses are a type of sauropod, the long-necked dinosaurs.** Of course when you use the word “brontosaurus” there’s always the chance someone will jump in with “There’s no such thing as brontosaurus” or something like that, since technically, brontosaurus turned out to be the same as apatosaurus, and since apatosaurus was named first, the brontosaurus name was replaced.***
So, brontosaurus. Floating. Here’s the thing: there are these fossil dinosaur footprints, called trackways, and some sauropod trackways are manus-only, meaning only the front two feet (“hands,” hence manus) put down tracks. The question being, how did this happen?
This could happen for dinosaurs because, according to Henderson’s models, the center of buoyancy and the center of mass of the sauropods isn’t necessarily in the same place. Center of mass is the place in an object where, basically, you can model gravity as acting on just that spot. On humans it’s in the torso somewhere, around the pelvis.
Center of buoyancy is similar; it’s the place in an object where you can model the buoyant force of the water/other substance it’s floating in as acting on just that spot. When floating, if your center of gravity isn’t aligned with your center of buoyancy, it’s like leaning too far over on the balance beam; gravity is suddenly opposed by nothing and you flip over.
Now model the sauropods. Evidence suggests that, like their modern-day relatives birds,**** sauropods had a system of air sacs in their bodies. Henderson’s modeling technique is interesting (slicing!) but I’m not going into it here. Suffice to say that when modeling where the center of mass and center of buoyancy are, those air sacs have to be taken into account or your physics will be very, very wrong.
Say these sauropods wandered into some shallow water (shallow for them, anyway). Gravity would push down on their center of mass, and buoyancy would starting pushing up on their center of buoyancy. According to Henderson’s model, apatosaurus/brontosaurus and diplodocus has a center of buoyancy a little in front of their center of mass, so their front legs started to lift off the ground while their back legs stayed. Camarasaurus and brachiosaurus, on the other hand, had a center of buoyancy a little behind their center of mass, so their hind legs started to lift while their front legs stayed.
Now you should be having hilarious mental images of sauropods punting around, half-floating with just two legs on the ground.
Have some pictures (from the Henderson article, colored dots added for visibility):
So that’s one way a manus-only trackway could show up: if a camarasaurus or brachiosaurus was punting around in the shallows, using just its front legs to propel it. And brontosaurus probably didn’t just sink; it actually might have floated a little bit. Even though it weighed like twenty tons.
*Or both. I have the model of this. And treasure it.
**When you read “long-neck,” if your brain went there: congratulations. You or someone you knew grew up in the ’90s!
***Even though everyone likes it more (and by everyone I mean me); taxonomy operates on a first-one-in-wins rule. This is also the reason that, if the new contention that triceratops is actually an immature torosaurus holds, then torosaurus will become triceratops.
****relatives, not direct descendants.
[note: this post originally appeared on August 10, 2010 at Original Blog (see here for details)]
I’m conflicted as to what to write about today. Solar sails are in the news, but the floatability of brontosauruses was recently mentioned in my presence and trust me, there is a history (of love) there between me and the sauropod buoyancy. Astronomy… dinosaurs… astronomy… dinosaurs…
My very favorite episode of Bones* is on right now, so I’m in a good mood. A bright, sunny mood. The dinosaurs will wait for a rainy day.
I have a powerpoint on solar sails already prepared, but I can’t just post it right up and tell you all to go to town because it’s full of equations,** so I guess we need to talk.***
So, the thing here: the Japanese Aerospace Exploration Agency (JAXA) built a solar sail, shot that puppy up into space, and the sail has now successfully unfolded itself and is ready to be tested as a method of actually steering its spacecraft.
Solar sails work basically like boat sails, except instead of being pushed around by wind, they get pushed around by light. Yay for transparency in naming.
Wait, you might say, that is ridiculous. Light cannot push things around.
Oh, but it can, through the phenomenon named radiation pressure for reasons which are, again, hopefully obvious.
Light, you see, has momentum. Exciting! So do all things that are moving. Usually when we talk about momentum we talk about mass times velocity, but light is made of photons, which don’t have mass. But relativity provides for photons to have momentum anyway. The important thing to take away from this paragraph is that photons have momentum; why is not immediately relevant.
So. Photons whiz along at 186,000 mi/hr or 3×10^8 m/s, with momentum. And then they collide with things, things like you and me and everything we look at, and they impart some or all of their momentum to the things they collide with, exerting pressure on them. Radiation pressure.
Radiation pressure is exceedingly gentle; at 93 million miles from the sun (also called 1 AU, or astronomical unit; about the distance the Earth orbits at), the pressure of the sunlight, around 4.6×10^-6 N/m^2, is incomparably lighter than the brush of a moth’s wing.****
So on Earth, radiation pressure isn’t going to make much of a difference. But in space? It’s a vacuum, so there’s no air pressure, no wind, and once you get out from the influence zone of large objects, no gravity… radiation pressure, gentle though it is, isn’t facing any competitors. So theoretically we should be able to send up some kind of space robot, attach a giant sail to it, and use that sail to float that robot around space like an awesome space-sailing-boat-type-thing.
Sounds awesome, right? Clearly it is or I wouldn’t be writing about it. But because radiation pressure is so gentle–and the farther from the sun our space-boat-robot goes, the gentler the radiation pressure gets–to get up to speeds fast enough to go anywhere in a reasonable time, you need your sail to be both large (to catch as much light as possible) and lightweight (because the more payload the sail carries, the less effect a given amount of radiation pressure has). And it’s not like it’s easy to get large, delicate, lightweight objects into space.
So we can’t send a sail up ready-to-go, it would tear or run into stuff or burst into flame on the way. You need to roll it or fold it or something. We’ve attempted solar sails before, but they failed on launch or wouldn’t unfold and things of that nature.
But now Japan has launched IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun),***** and it unfolded, and now they’re going to test how the sail steers and moves its little robot payload around. Which is awesome: advent of new technology!
Additionally, artists’ renderings of solar sails look super-cool.
*The Witch in the Wardrobe. It makes my heart want to explode in a shower of confetti and stars and other tiny hearts full of sparkles.
**I have two powerpoints about the floating dinosaurs, also full of equations.
***Also, the slides are slightly nonsensical without accompaniment
… as it should be.
****Though, when panicked, luna moths can actually get some surprising force behind there. I know this because I have been repeatedly smacked in the face by one. But don’t let this anecdote distract you from the point: radiation pressure is minute.
*****No points for spotting the reference, sorry.
[note: this post originally appeared on July 20, 2010 at Original Blog (see here for details)]
Actually, it feels exactly like summertime, what with the 90 degree temperatures the climate has seen fit to inflict on this area lately.
And honestly, with that summertime, I don’t feel the urge to make an attempt at insightful analysis of, like, breaking news. Or non-breaking news. I feel the urge to read novels out in the park and eat Klondikes and go hiking.*
Hiking last weekend I learned about a fun new plant. Most people already know about poison ivy, the scourge of campers and hikers and other outdoorsy people everywhere. Poison ivy is a lovely little vine, identifiable by its three leaves, which lurks and gets it oils all over the skin and then gives you a nasty rash. I learned to identify it via my parents, who pointed it out with dire warnings since I was born, approximately.**
Poison ivy’s damage is inflicted by the urushiol oil in the plant; the oil tends to induce an allergic reaction, called allergic contact dermatitis; the same kind of reaction can be induced by other irritants, including metals like nickel. But the degree of reaction produced by poison ivy contact varies from person to person and sometimes even within a person’s lifetime.
What I learned about from the signpost in the campground was wild parsnip.
Wild parsnip works differently from poison ivy. Instead of allergic contact dermatitis, wild parsnip hurts you with phytophotodermatitis. It looks harmless, until you get the sap on your skin. The sap sensitizes your skin to ultraviolet light–the same kind of light that gives you sunburn–and so when ultraviolet light shines down on the skin (which it will, since you’re outside running into wild parsnip), you can get burns, blisters, and even brown marks that can last for years.
*I can smell someone’s fire through my window and it smells like outdoors and wonderfulness.
**Once I hugged a tree covered in poison ivy and evaded leaf contact by pure luck. The tree-hugging was on purpose; the poison ivy presence was not. Since then: paranoia.
[note: this post originally appeared on May 25, 2010 at Original Blog (see here for details)]
Recently, I had to buy new exercise pants because my old ones were too big.*
In that spirit, I’m trying to develop walking as a habitual form of exercise (as opposed to hiking, which I generally get to do only on weekends, though I admit I kind of blend them around in my tracking journal.)
So: does it really?
Before we get to the current study, let’s discuss how, exactly, 21 days might have infiltrated our collective consciousness.**
It all seems to stem from Dr Maxwell Maltz, a plastic surgeon who wrote a self-help book called Psycho-Cybernetics. Wherein he apparently made the (anecdotal) observation that it seemed to take his patients who had had arms amputated about 21 days to stop feeling phantom pains in their missing arm.***
I have to tell you, arm amputation has never played a major role in my life, so I don’t think that’s really applicable here. Maltz never made a formal study of the 21 days claim.
But now! Dr Phillipa Lally and her co-authors have done a study of habit formation. It’s just one study, but still: at least they have some actual evidence. What they found, perhaps unsurprisingly, has nothing to do with a magic 21-days number.
Instead (page 10),
The average modelled time to plateau in this sample was 66 days, but the range was from 18 to 254 days. We were only able to ﬁnd one statement in the literature discussing how long it takes to for a habit. This was from Ronis, Yates, and Kirscht (1988), who argued that a behaviour is habitual once it has been ‘performed frequently (at least twice a month) and extensively (at least 10 times)’ (p. 213). Our study has shown that it is likely to take much longer than this for a repeated behaviour to reach its maximum level of automaticity.
So the average time in Lally et al’s study to form a habit was 66 days, but it ranged between 18 and 254 days. Numbers, you will note, which are not 21.
Also on page 10,
It is interesting to note that even in this study where the participants were motivated to create habits, approximately half did not perform the behaviour consistently enough to achieve habit status.
The study was performed with people who were asked to pick a habit that they would like to have for the study, so they were internally motivated to get their habit, but half of them didn’t form the habit anyway.
You may have guessed by now that page 10 is the ‘discussion’ section:
Comparing increases in automaticity score over 2 days when the behaviour was either performed on both days (mean increase
= 0.79) or there was a missed opportunity in between (mean increase = 0.55) shows that a missed opportunity did not materially affect the habit formation process. This is encouraging for researchers designing health interventions which aim to establish healthy habits. It suggests that although repetition of a behaviour is required in order to form a habit, some missed opportunities will not derail the process.
So it may be that you can miss a day and still successfully form your habit. Which is nice for me, because I’m skipping today’s walking because of blisters.****
***I would like to substantiate this by getting the actual book, but my library’s catalog indicates the only version it has is a translation in Urdu. Seriously. If I ever find one in English, I will update this footnote.
****Blisters form when friction separates layers of your outer skin and the intervening space fills with fluid. Even though it doesn’t feel like it, the point of the blister is actually to protect the tissue underneath it with the fluid cushion.
[note: this post originally appeared on April 13, 2010 at Original Blog (see here for details)]
Last Wednesday, I went to see Great Big Sea play*. Since then I’ve listened to pretty much nothing but, and I listen to music in the background for quite a lot of my daily routine.
Yet somehow, as I’ve sat here in my quiet apartment trying to think of what to write here, my brain has had “I’ve been waking up your neighbors barking up your tree” on infinite loop repeat. It’s roughly five seconds of an almost four-minute song, and I haven’t listened to Bon Jovi in weeks**. The worst part is that I actually know the rest of the song, but it just won’t play the whole thing.
I have an earworm.
The name earworm is a literal translation of the German ohrwurm***. James Kellaris, at the University of Cincinnati, characterized the earworm as a cognitive itch that our brain wants to scratch. Apparently women, musicians, and the anxious are most prone to earworms.
The music that is earworm-inducing tends to be repetitive, simple, and have what Kellaris calls an “incongruity,” something that sticks out, like a shifting time signature.
A 2005 study at Dartmouth found that the auditory cortex in your brain is responsible. If a song is played to you, the auditory cortex activates as you listen. If you’re familiar with the song, and the song is turned off, the auditory cortex will just keep going. The fake song-hearing appears to be your brain following the reverse of path of the what it would do were the song actually playing, though exactly why you catch the earworm no one knows.
According to a study by British researchers Philip Beaman and Tim Williams, the best way to make an earworm go away is to ignore it. I usually go with ‘sing other songs.’
*it was the greatest 2 hours and 49 minutes of my life.
***and is not related to the actual insect corn earworm… I hope.
[note: this post originally appeared on March 23, 2010 at Original Blog (see here for details)]
St Patrick is supposed to have driven all the snakes out of Ireland. Note ‘supposed’: it’s generally considered that the snakes were a metaphor for non-Christian religion, not actual snakes.
Because Ireland has never had actual snakes on it.
As the National Zoo points out, the first snakes evolved around the same time as T Rex did, about 100 million years ago, which means the globe looked something like this. Or this, for the all-at-once map view.
Really ancient snakes did not live in Ireland because Ireland was underwater.
All right. If we fast-forward a bit to around 14 million years ago, Ireland is now above the sea and the world looks pretty much as you’d expect. But, there are still no snakes in Ireland, because Ireland… is an island. And snakes aren’t great at swimming**.
Snakes are cold-blooded, which means they don’t regulate their own body temperature; they use their surroundings instead***. This is not an ideal setup on a glacier; if there were any snakes on pre-glacial Ireland, they became snakesicles.
Afterward, Ireland was still separated from the island of Great Britain by the Irish Sea. Snakes aren’t any better at swimming, so Ireland remained snake-free, saintly intervention not required****.
*Yours or someone else’s. Authenticity optional. 34.5 million Americans claim some Irish ancestry, according to the US Census Bureau. Not to mention the many people blessed with the name ‘Erin,’ especially in the ’80s (you can look at the Social Security Administration’s baby names site for further details).
[note: this post originally appeared on March 16, 2010 at Original Blog (see here for details)]