I’m starting my own business, doing freelance science education, writing, blogging, podcasting, and anything else that comes my way.  (Got a contact or job for me?  Send it my way at riggmailgeek at yahoo dot com — resume here.  My experience is broad, but in a nutshell I’m well-suited to create innovative education and communication programs about science for the public, or for K-12 teacher professional development, using writing, podcasting, and inquiry-based learning).  So, dear readers, got any clever ideas for a name?  I’m thinking the obvious “sciencegeekgirl incorporated” though I’m not quite sure if the “incorporated” is kosher given that I’ll be an LLC.  Ideas?  Tips on setting up your own freelance biz?  All help and creativity appreciated!

I finally just checked out the Pathways Project, which provides pre-recorded video answers to your questions about how to teach physics.  Color me impressed.  I chose a teacher from the drop-down menu and asked a question — in my case, “How do I teach electrostatics?”   I was told that my chosen teacher (Paul Hewitt) didn’t have a pre-recorded answer, but two other teachers did.  I was treated to a detailed discussion by Chuck Lang (about 3 minutes) on how he presents electrostatics to his students.  I was also given a choice to ask related questions (“Should I teach electrostatics?”, “How can I use computers to teach electrostatics?”), as well as to ask similar questions from Compadre (the online digital archive of all things physics-education-related).  What a great way to get mentoring from experienced teachers who I haven’t even met!

I’m cross-posting this from a fun little discussion we just had over at Morning Coffee Physics. (Perhaps ironically, all my posts took place in the wee hours of the night, sans coffee). Jasper wrote a really neat little post about why snow sparkles and I asked him if he knows why snow crunches underfoot when it’s cold.  It’s been really cold (really cold, whimpers this recent transplant from San Francisco) in Boulder lately and my tires and feet have been making cacophonous sounds in the snow.  I always had this sense that maybe it was because of snow crystals rubbing together.

Jasper wrote:

I did a bit of googling. From the few (sketchy) sources I saw, it looks like the crunch sound comes from the sudden release of air from the air pockets in a pile of snow. That I can believe, however, one explanation includes the following:

“When you walk on snow, your boots apply pressure. If the snow is warmer than about 14 degrees F (-10 degrees C), the pressure partly melts the snow, which “flows” under your boot instead of breaking. If the snow is colder, it does not melt, and your boot crushes those innocent ice crystals, accounting for that plaintive scrunching sound.”

As elegant as that explanation sounds, I suspect it won’t really add up… (literally even). It sounds a lot like the physicist’s myth of ice skating being explained by a similar process (Pressure from skate -> melting ice -> sliding). In one of my classes we did this calculation and it turned out that the freezing point of ice under a skate would only change by about 1 degree maximum. I suspect something similar for the preceding claim about crunching snow.

Going on physics intuition alone… I’d probably say the temperature dependence of the squeakyness of snow has more to do with the temperature dependence of the structure of the snowflakes. Maybe the shapes that snow crystals take on at low temperatures are better at making noisy air pockets… * shrug *

I shared his skepticism of the online explanation that he found.   It seems implausible that crushing would create that sound, but maybe my experience misleads me. It just seems like most of the sound is coming from the sides of my shoes in the snow, creating friction, rather than from my shoe coming down.  If I step straight down, rather than grinding my foot sideways into the snow, it is quieter.  But I also don’t think that a “different shaped snow crystal” explanation works for me, since the snow has already fallen to the ground and thus its crystal shape is already determined.  Once it’s on the ground, it crunches when you walk on it if it’s really cold, and doesn’t if it’s not.

After I wrote all that, I found a good link that seems to support what I just wrote (don’t you love it when that happens), and also incorporates the idea of different shaped snow crystals, but not in a temperature dependent way.

There are two — no, actually three — physical factors affecting the crunching / noncrunching of trodden snow. The mechanism behind all three is the same — lubrication, good or bad. When snow does NOT crunch, then the grains / crystals in the snow are well lubricated. When snow DOES crunch, then lubrication is poor. The lubricant is of course water in all cases, coming from two sources, both of which are temperature-dependent:

(1) Ice crystals are always surrounded by a very thin layer of water (a phenomenon already observed by Michael Faraday). The thickness of this layer varies with temperature, ranging from a one molecule thick layer at about -10 oC, to hundreds of monomolecular layers at -1 oC.

(2) Pressure lowers the melting point of water. If you step on snow, then the crystals are pressed against each other. The ice at the contact points may melt and create a thin lubricating layer of water. Unfortunately, the pressure from the soles of your shoes is far to small to melt snow at any temperature, so this factor, interesting as it my seem in itself, is rather irrelevant in this connection.

(3) The third factor is the shape of the ice / snow crystals: crystals with a greater number of pointed edges crunches more readily. An extremely pointed structure of the snow crystals can sometimes offset the other factors, making snow crunch even when it is warmer than -10 oC.
It is difficult to say how these phenomena interact in order to lubricate (or not lubricate) the snow crystals, but in any case something seems to be happening at around -10 oC, enough to make a sharply noticeable difference: if it is colder than about -10 oC, then snow crunches, if it is warmer, then it usually doesn’t.

Ten-degree rule of thumb

These factors, taken together, determine the precise temperature at which snow starts crunching. But the -10 oC rule is a surprisingly good rule of thumb, if you want to predict whether or not you will experience the nice crunching sound of snow when you take a walk at Christmastime.

But if anyone knows something more, please let us know!

That’s the title of a very well-done  book that I just finished (Who’s Afraid of Marie Curie by Linley Erin Hall) which outlines a lot of the challenges facing women in science, technology, and medicine, from grade-school to college, graduate school, post-doc, and faculty and professional positions, plus concrete recommendations based on the research on how to improve the numbers of women in science.

For example, a gender-fair classroom, she says, would offer boys and girls similar amounts of criticism and praise, since girls tend to get non-specific feedback like “that’s good,” or “OK,” which doesn’t actually help them improve.  Teachers need to push girls to work on problems that challenge them, instead of “rescuing” them.  They’re smart enough to figure it out (whatever problem “it” might be), and it’s important that they develop that confidence in their own skills and abilities.

There is also a very good summary chapter on the research on gender differences in scientific ability.  As you might have guessed, males and females are more similar than they are different on most (but not all) aspects of mind.  She reviews the questionable ability of standardized tests (like the SAT) to demonstrate gender differences that are real (boys tend to score higher on the SAT than girls, but girls’ SAT scores tend to underpredict their grades in college math classes).  She talks about stereotype threat, which I’ve written about before.

Most of the book focuses on career choices facing women, however.  If you’re a woman considering a career in science or tech, I’d suggest giving this book a gander.  Some interesting factoids:

1. Female scientists and engineers tend to marry other scientists, or at least other professionals.  68% of female physicists are married to other scientists, but only 17% of male physicists are.  Women seem to enjoy having this compatibility and understanding in their partner, plus men outside of science can be intimidated by women scientists.  However, this can result in the “two-body problem” where both members of the couple try to find similar positions in the same town.  It can also penalize the woman because she ends up being more responsible for domestic duties, but both members of the couples have demanding careers.
2. Unconscious bias can play a large role in discrimination against women in science.  I’ve written about this before (Advice for Girls in Science and the Meritocracy).  It can be very hard for women to know they’re being treated differently.  In one study (looking at evaluations of postdoctoral fellowship applications) women had to be 2 1/2 times as productive as a man to get a similar rating of competency.  Another study looking at letters of recommendation for medical school applicants found that letters written for women tended to be shorter, and tended to include phrases that raised doubts about her competence.  <sigh>
3. Women tend to under-estimate their ability, whereas men over-estimate theirs.  I’ve seen this to be true, and a friend of mine who leads outdoor activities has also remarked upon it.  When a man says that he’s sure he’s in good enough shape to do a long trek, he’s more doubtful.  And when a woman isn’t sure if she can do it, he usually encourages her, because experience has shown him that they’re usually selling themselves short.  In undergraduate life, this can mean that women are more likely to leave the sciences than men, because they’re more likely to doubt their ability when challenged.  This can be particularly prevalent in “weed-out” courses.  One study found that while women regained some of the confidence they lost in weed-out courses, they never fully recovered.  Those courses did permanent damage to their sense of their ability to succeed.
4. Men spend more time trying to figure things out on their own. Women ask for help sooner.  But women might clam up, she says, when surrounded by men who aren’t asking any questions.  I’ve had this experience myself, many times.  It’s part of the reason I left the physics major.  I wanted to work on homework with a couple of the guys from class (there were no other women), but they just sat and worked on their own, and blew off my questions and attempts to talk about what we were learning.  I concluded that they knew this stuff better than I did and if I was cut out for this, it should be easier for me.  (Years later, my instructor told me I was one of the best students in the class.  Why didn’t he say so earlier?)
5. Men tend to have an instrinsic sense of self-worth whereas women are socialized to rely more on the approval of others.  This ties in to the self-confidence problem, and helps explain why women tend to leave the sciences.  When we’re used to feeling good about what we can do when others give us praise, then when things get tougher in college and grad school, it’s easy to get demoralized.  It seems that while both men and women find the later stages of scientific training demoralizing, it’s tougher for women.  Men will tend to stick with it.  I know that this was true for me, and still is.  I feel good in response to what others say about me and my abilities.  I know that other studies have shown that it’s not good to believe that failure reflects poorly on your self-worth.  If you fail a math test and think that means you’re stupid, then you’ll just avoid math.  If you fail a math test and think that you should have studied harder, then that gives you ammunition to improve in the future.  I wonder if that has any bearing on the intrinsic/extrinsic sense of self-worth stuff.
6. Some women go into science because they can. That is, there’s this sense that if you’re smart enough to do science, then you should.  Social science or other fields are not as high of a calling.  Plus, we need women in science as role models.  So some women feel guilty if they leave science.  Again, I know this was true for me to some degree.  Physics was the hardest science could get, and so I wanted it….
7. Fathers’ involvement with their daughters is important. Women who were only children or didn’t have any brothers reported (in the author’s small sample) having more mentorship from their fathers in tech and science.  As an only child, and the daughter of a chemist, I found this observation very interesting.  One female graduate student observed, “I wonder if part of the reason I’m comfortable with science is that my father didn’t have a son to help him.”  Myself, I always wished my dad had brought me down into his woodshop and taught me to hammer things together.  But he did take me fishing.  I’m a bit of a tomboy, in some ways, perhaps because of that relationship I had with my dad.  And I wonder if I got more mentorship in science from him than I think.
8. Women often have lower salaries than men because they don’t ask for more money. This is the primary message of a book called “Women don’t ask” by Babcock and Laschever.

The book had a wealth of websites and resources for encouraging girls in science, and for professional women in science to connect.  I’m not sure how much of that I’ll put in here, but if there is interest let me know and I’ll be sure to do so.

A few cool things about science that relate to the holidays.  I wrote this *before* Christmas, but, oh well, better late than never?

Dot Physics has a wonderful post on why Christmas tree lights stay lit even when one of them burns out, which is an unusual way for a series circuit to work.  Some nice explanations using Kirchoff’s laws make this a wonderful little post to stimulate a science lesson for the season.

From Sebastien Martin

I have an old post on why it’s a myth that no two snowflakes are the same shape.

And Morning Coffee Physics has a delightful little post on why snow sparkles. This is just my kind of science — gorgeously explanatory post about something we see every day.

Sebastien Martin at the Exploratorium has some beautiful images on his Flickr site showing how they used Christmas lights to demonstrate resonance and harmonics (see picture at right).

Steve Spangler Science gives you some ideas to deck the halls…holiday decorations with science.

And then of course there’s the old favorite Instant Snow (video on Teacher Tube).  Insta-Snow is made from sodium polyacrylate, a water-absorbing polymer.

And on the Ellen show….

Yup, it’s time for those “top 10″ lists for 2008.  I don’t generally post other peoples’ lists here, but heck, this is one area where I know that I haven’t been paying close enough attention to know what’s important.  So here is an edited version of the Physics Findings for 2008 from Physics News.  Phil Schewe does such a great job with these, they’re a delight to read.  You can read the whole thing at Physics News Update (and subscribe to their e-newsletter).

TOP TEN PHYSICS STORIES OF THE YEAR

The following list was chosen by editors and science
writers at the American Institute of Physics and the American Physical
Society.  It winnows a wealth of discoveries into the following ten
topic areas, which are listed in no particular order.

SUPERCONDUCTORS

What’s new-discovery of an unusual class of materials made from iron
and arsenic.   Superconductors don’t lose any energy when electricity
runs through them, providing they’re chilled to very low temperatures.
Superconductors are used in specialty applications where high
electrical currents are needed, such as in MRI scanners at hospitals or
in the magnets used to steer particles at atom smashers.  …

The new iron-arsenic materials are the first relatively
high-temperature materials that remain superconducting above a
temperature of 50 K that don’t contain copper; the copper materials are
brittle.  Researchers hope that the iron-arsenic version might lead to
the more practical manufacture of superconducting wire.   Furthermore,
having a new class of materials to study should help theorists
understand how high-temperature superconductors work in the first
place.
Background: A summary of work in this area can be found at Physics
Today, May 2008; APS survey of topic.

LARGE HADRON COLLIDER

What’s new—the LHC, the world’s largest scientific instrument,
started operations in September.  At this huge particle accelerator,
located underground near Geneva, Switzerland, two beams of protons, each
traveling at unprecedented speeds will be smashed together.  The goal is
to create exotic new particles that can’t be observed in any other way
except in the tiny fireball created by such violent collisions.  ….

Problems with some of the apparatus forced a premature shutdown
…  General operations should resume in summer 2009.
Background: a summary of the magnet malfunction which brought testing to
a halt in September and a timetable for operations are available here.

PLANETS

What’s new-planets orbiting distant stars have been imaged directly, and a host of interesting results have come back from spacecraft hovering near the planets in our own solar system.  Extrasolar planets, planets orbiting far-away stars, had been detected indirectly by watching what happens to the light coming from the star.  But now the glare of the star has been blocked sufficiently that the extrasolar planet itself could be imaged.  The Gemini, Keck, and Hubble telescopes provided pictures. Background summary here.

In our own solar system, at Mercury, the Messenger spacecraft  made  first-ever maps of large portions of the surface. At Saturn, the Cassini  craft found geysers near the south end of the moon Enceladus.    At Mars, measurements made by several craft strengthened evidence in favor of sub-surface glaciers outside the polar regions. Meanwhile, the Venus Express craft recorded pictures at several wavelengths, facilitating, among other things, a better knowledge of clouds on Venus.

QUARKS

What’s new-unusual combinations of quarks were observed for the first time.  Physicists believe that an atom consists of one or more electrons orbiting a central nucleus.  The nucleus, in turn, is made of protons and neutrons, and these particles are made of something still more elementary-quarks held together by gluons.  … One discovery consists of the sighting of nuclear particles containing rare “bottom” quarks.  Background here.

[See the full article at Physics News Update for more on these experiments   -geekgirl]

FARTHEST SEEABLE THING

What’s new-seeing a flash of light from 7 billion light years away.
One of the brightest of all celestial objects is gamma-ray bursters,
objects that emit immense amounts of gamma radiation, the highest-energy
form of light.  The brightest-ever gamma ray burster was observed by the
Swift satellite.   Since looking out into space is equivalent
to looking back in time, this flash would have been coming from a moment
when the universe was only half its present age.  Publication in Nature.

ULTRACOLD MOLECULES

What’s new-first ever accumulation of molecules in large numbers and
at a temperature near absolute zero.  Using lasers to slow a gas of
particles down to near stillness is by now a standard method for
measuring the subtle properties of atoms.  Steven Chu, nominated to be
the Secretary of Energy, won a Nobel Prize for pioneering this subject.
Cooling molecules in this same way is difficult since molecules, made of
two or more atoms, have complicated internal motions.  But this year
several labs succeeded in first cooling atoms and then, at a temperature
close to absolute zero, getting them to combine into molecules. …
Background at http://www.aip.org/pnu/2008/split/875-1.html; figure
http://www.aip.org/png/2008/306.htm; PRL text and overview at
http://physics.aps.org/articles/v1/24

DIAMOND DETECTORS

What’s new-getting little imperfections in diamond to tell us about
how atoms behave like tiny magnets.  Diamond is made of a cross-linking of carbon atoms.  If one
carbon atom is missing from this network, the empty hole, in combination
with a stray nitrogen atom, acts as a sort of strange molecule in the
middle of all those carbon atoms.  This “molecule” can light up like a
little LED when you shine laser light in.  This in turn, can be used to
measure extremely weak magnetism.  Possible applications include data
storage for computers or high-sensitivity detectors. … See news summary at
http://www.aip.org/pnu/2008/split/858-1.html.

COSMIC RAYS

What’s new-experiments settle one mystery and uncover others.  Cosmic
rays are super-high-energy particles whizzing through the cosmos.  When
they smash into our atmosphere the rays turn out mostly to be ordinary
particles, such as protons or electrons, but with energies thousands or
millions of times higher than particles speeded up at accelerators on
Earth. [See full Physics News Update article for new results -- there are many!  -geekgirl]

LIGHT PASSES THROUGH OPAQUE MATTER

What’s new—getting light to behave in a new way. When light strikes
an opaque material like milk most of the radiation is scattered; little
of it passes through the sample.  But in an experiment at the University
of Twente in the Netherlands, much more of the light can be made to
traverse the scattering material if beforehand the wavefront of the
incoming light is shaped by special filters. Background summary.

MACROSCOPIC FEEDBACK COOLING

What’s new—Scientists at the AURIGA lab in Padova, Italy have cooled
a one-ton aluminum bar to a temperature below 1 milli-kelvin using
special electrical circuits.  The bar is part of a detector designed to
measure passing gravity waves from space.  Using sensitive magnetic
sensors and feedback coils, the ringing of the bar (which is essentially
a large tuning fork) at one characteristic frequency was cooled from an
equivalent temperature of 4 K (the temperature of the bath of liquid
helium in which the bar sits) to a temperature of about 0.17 mK.  Lower
temperatures than this have been achieved with this feedback cooling
technique but only with much smaller masses.  Background: essay and PRL
article at http://physics.aps.org/articles/v1/3

Phillip F. Schewe

For this week’s episode of Science Teaching Tips, I’ve got a story from a veteran teacher about her first year of teaching — which was quite unusual.  She was placed in a rural school in Guatemala.  You think you’ve got it tough?!  Hear about her challenges in Episode 63 – Teaching Abroad.

Here are some great gems from some really old posts over at Swans on Tea. Thanks to Rhett at DotPhysics for the technical assistance.

Robots doing amazing things:

Carbon dioxide is heavier than air (neat thing to try at home)

Weird psychology trick (how does he do that?)

I just read this lovely discussion of how a more open scientific culture (think open-access science) could improve the collective memory of science. This was on the Back Page of APS News (subscribers only) and here is the author Michael Nielsen’s blog post about the topic too, with some additional information. His basic premise is that we don’t exchange scientific information freely, in a sort of public scientific marketplace, because there’s a lack of trust like there is in the consumer marketplace. He writes:

In science, we’re so used to this situation that we take it for granted. But let’s compare to the apparently very different problem of buying shoes. Alice walks into a shoestore, with some money. Alice wants shoes more than she wants to keep her money, but Bob the shoestore owner wants the money more than he wants the shoes. As a result, Bob hands over the shoes, Alice hands over the money, and everyone walks away happier after just ten minutes. This rapid transaction takes place because there is a trust infrastructure of laws and enforcement in place that ensures that if either party cheats, they are likely to be caught and punished.

If shoestores operated like scientists trading ideas, first Alice and Bob would need to get to know one another, maybe go for a few beers in a nearby bar. Only then would Alice finally say “you know, I’m looking for some shoes”. After a pause, and a few more beers, Bob would say “You know what, I just happen to have some shoes I’m looking to sell”. Every working scientist recognizes this dance; I know scientists who worry less about selling their house than they do about exchanging scientific information.

I just loved this analogy. It’s absurd, yet understandable, how hard it is for scientists to collaborate. But there’s a ton of stuff being written now about open access and what it can do for science, on my blog and others.

That long blog post title is the summary of a very interesting piece of research just written up in Cognitive Daily.  This is worth going over and taking a peek at the original post, because it’s quite an interesting piece of research.

The research question was whether people’s memories follow a predictable pattern.  After all, we seem to remember more stuff from our 20′s and 30′s than, say, our 60′s.  The researchers found, basically, that more life-defining events happen in our 20′s and 30′s (like marriage, having kids) and those events create more long-lasting memories.  I’m grossly paraphrasing here, so take a look at the original post for the clearer picture.

Cognitive Daily says:

This corresponds well to other researchers who have found that immigrants remember more details about the years surrounding their time of immigration than non-immigrants. So if you immigrate in your 30s, you’re more likely to have memories from your 30s than someone who immigrated in her 20s. Other studies have found a memory bump in people from Bangladesh corresponding to a period of political unrest in that country. So it seems that our memories are affected more by the events in our lives than just the physical development of our brains. We’re not all destined to remember more of our teens and 20s than other years; we’re just more likely to experience significant, life-changing events in those years than others.