ClarifyScience comments

2012 March 8, Thursday

No post, just a place to collect comments.

ClarifyScience placeholder post

2012 March 8, Thursday

The first real post is expected in 2012 March or Q2.

Mis-stated matter

2011 June 6, Monday

[Some late-night silliness…]

Cat drinks water from a glass
CC-BY-NC-SA @ 2011-06-06

Cat drinks.
Dog thinks.
Dog asks, “Is that water in your glass, a solid, liquid, or a gas?”

Cat thinks.
Cat winks.
Cat replies, “Meow. Yes.”

Dog frowns.
Dog barks.
Dog inquires, “WooTF?”

Cat explains.

“Against the glass, the water pressed, shear force you can’t neglect.”
“And so, a solid.”
“Above the surface, in humid blending, air and water dance.”
“And so, a gas.”
“Within these thin boundaries, bulk water lies, sticky and slidy.”
“And so, a liquid.”

Dog protests, “But… but the meat of it… only the liquid matters!”
Cat corrects, “State a problem, before discarding skin.”
“A mosquito larva, breathing snorkeled microclime, would disagree.”

Dog ponders larval plight.
But with wagging tongue, recites, “It’s a liquid iff it takes the shape of its container.”

Water droplets sitting spherically on a leaf
CC-BY-NC-SA @ 2011-06-06

Cat licks whiskers.
Cat licks dew drop.
Cat suggests, “Dogs should know better than that.”

Cat looks at water droplet
CC-BY @ 2011-06-06


Science education content, come the revolution

2010 October 22, Friday

Morning sunlight brightens the classroom. Casey opens a tablet.  It’s 9:05.

Sounds like the beginning of a “tablets with revolutionize evolution” post, doesn’t it?  But no.  I’ve been bending peoples’ ears about content.  Descriptive content.  For K-grad science education.  The stories we tell students about how the physical world works.  And someone at dinner asked, “Ok, say you’re right.  What does the revolution look like?

The teacher noticed the sunlight too.  So she begins the morning with astronomy.  Casey’s tablet says, “The Sun, is a Big, Hot, Ball!”  Casey exclaims, “A ball!”.  Casey likes balls.  On the screen, there is an interactive white ball.  With spots.

That’s it.  There’s the revolution.

Missed it?  It’s there at the end.  It’s easy to miss.  No, not the spots.  No, nor the interactive – how could anything educational not be interactive?

It’s the “white”.

Huh?  Why?  Compare to the present.

Have you played the “ask an Astronomy grad student the Sun’s color” game?

Q: What color is the Sun?
A: yellow

Q: What color is Sunlight?
A: white

Q: Explain how those two can be?
A: <silence>

As embarrassing as this is for astronomy, it’s not the problem.  The problem is you can easily do worse than “yellow”.  Just ask a non-Astronomy first-year physical sciences grad student.  A most popular answer is “The Sun doesn’t have a color.  It’s lots of different colors.  It’s rainbow.”  So not merely a misunderstanding of a poorly taught star classification scheme.  Instead, a basic ignorance of color and light.

Casey’s tablet shows a large white square.  Cartoon prisms float across it, breaking white into rainbow.  Casey finger paints the rainbows back together to white.  Red light blends with green into yellow, and yellow with blue into white.  It’s 9:15.

Some afternoon in the not too distant future, there will be a second-grade student named Casey.  And Casey will have a sounder understanding of color, and of sunlight, than your current average science grad student.

And that matters.  A great deal.  Not so Casey can win at trivial pursuit.  Or eventually become a slightly better graduate student.

Step back.  It is miraculous that science works.  That the universe is understandable.  That pieces of knowledge plug together.  That where a piece doesn’t fit, you know you have misunderstood something.  And can go back and figure out what.  That there is such a rich tapestry of connections between the pieces.  That the more you understand, the easier it becomes to learn more.  And to exercise that knowledge.

But all that only works if you get your descriptions right.   If instead, most of the pieces you are handed are broken and misshapen, and all are misunderstood, then you have a rather different story.

A story about a shallow mess of a pile of decaying pieces.  Of incorrect and misremembered and disconnected trivia.  Of stamp collecting, not insight.  Of Harvard Business School grads not knowing what makes summer from winter.  Of physical science professors unconnected with biology, not knowing RNA from DNA.  Of most introductory science students remaining unclear on most of the few concepts taught, for large values of most, and small values of few.

There’s nothing unavoidable about this condition.  It’s just not one we’ve cared enough about to change, given the effort required.  And lack of funding.  And lack of recognition.  With the collective heavy lifting needed, and largely absent, being from the science community.

It is wonderful that we can dig far enough out of this mess to allow research to happen.  But getting content pervasively right?  And beyond that, getting it pervasively insightful?  That’s a necessary but not sufficient condition to science education ceasing to be a disaster.

Oh, and that clueful Casey some future morning?  It’s not just Casey. It could be most of Casey’s cohort.

Casey’s friend changes the temperature of the ball.
“I… I can tell what temperature you did, by what color it is!”
“What’s a Sirius?”

(This post is second “write, don’t revise, just post immediately” effort.  The alternative, setting things set aside for revision, regrettably isn’t resulting in posts.)

Printable paper Earth globes

2010 July 22, Thursday

cube globe

Map Projections: Polyhedron Maps contains printable paper Earth globes. Paper craft world maps. In a variety of numbers of sides.  Fewer sides mean easier construction, but a less round and more distorted “globe”.

Tetrahedron, octahedron, cube, dodecahedron, icosahedron, truncated icosahedron, cuboctahedron, rhombicuboctahedron, and soccer ball Earth globes.

Because the site is poorly keyworded, people find my Making globes of the planets instead, when this is what they really want. Thanks to the most recent and enthusiastic correspondent, who prompted this post.

I encourage comments with links to similar sites.
One is JAXA AMSR Paper Craft [via Earth Science 3D Paper Models and Toys ]

Other ideas:
– The blank globes available for assembly practice could instead be used for “draw or paint your own globe” art and geography projects.
– It would be nice to have a suite of topical globes, so any time one is teaching a science topic (global winds, currents, biomes, rainforests, population density, crustal plates, geologic periods, etc) it would be easy to print out and assemble a little “globe” to make it tangible.
– If you are teaching polyhedra in maths class, or projection, why not have some pretty examples like these?

Helium balloon – heading for the stars!

2010 July 19, Monday

My wiki project (“Extreme-effort descriptive content for K-grad science education”, aka “Science content doesn’t have to suck”) is on hold, that I might focus on getting a job. Sigh. But folks keep saying I should blog more (like, at all), and this dreadful quote just went by, so here goes…

At that point, in accordance with the familiar, enduring magic of helium, it will weigh less than nothing at all.
[From The Man Who Would Fall to Earth, on page 2. The author does better later.]

My usual reaction to dreck is to think “There are so many wonderful stories which might be told instead.  We sooo need a wiki.  Stories like…”.


Escape! Free at last!
Helium heads for interstellar space!
Alpha particles going home!

What’s the story of this balloon? Or, punting the rubber, of the helium bit?

It’s impossible to do this for real. That would take weeks, or months, not the few hours I have for this post. Thus the need for a wiki. But some highlights are clear.

Briefly, the big picture includes:

  1. atmospheric He is headed out of the solar system,
  2. and it is alpha particles from the decay of heavy nuclei,
  3. which were synthesized in the supernova which triggered solar system formation.

In slightly greater detail,

  • Escaping the balloon. I’m unclear whether it’s a rise and pop, or a float and leak. Both stories have nice linkage to others, including weather and superpressure balloons, surfacing divers, H and He sneaky leakiness, etc.
  • Near-term journey. Atmospheric outgassing; blowing in the solar wind; termination shock; entrainment; and ISM.
  • Long-term journey.  I don’t know the numbers.  What’s a free He going to do around here for the next few Gyr? What are the odds of getting into another star?

Then, looking backwards…

  • Industrial extraction, storage, distribution, and economics.
  • Long-term experience of a heavy nuclei on earth. Living in the decay chain, waiting for your turn to go. Neutralization; diffusion; reservoir caps.
  • Supernova: unstable nucleosynthesis; hell; trigger shock. Solar system formation.
  • Getting from big bang to nova. Filament flow; galaxy mergers. I’m unclear on whether an earlier stellar experience is likely or not.

The hard part is gathering the information.  Only then, the very much not as hard part of generating correct and fun and enlightening end-user content.  Here faked carelessly for crude illustration.

ME: So, you’re a Helium atom?
He-p: Yep, that’s us.  Two protons, two neutrons, and some electrons we picked up.
ME: And you’re headed for space?
He-n: We are headed for the stars, man!  By tomorrow we’ll be mixing with the atmosphere.  Odds are an Myear from now, we’ll be out of the atmosphere and into space.  Wind at our back, blazing along, half a Mm per second.  A century to the wind wall,
ME: heliopause?
He-n: yeah, and then depending on what time of year we leave earth, we’ll either surf the bow wave for time, or wave sayonara.  Bye bye Sol.
ME: A million years? That seems a long time, no?
He-n: We’ve stuck on this rust ball in unstable nuclei for the last 4.6 Gyear. Another 0.001 Gyear?  No problem.  Way better than say waiting 8 Gyear for earth to vaporize.
ME: What are your long term plans?
He-p: We don’t know yet.  Hang out in the local interstellar cloud for a bit, of course.  Or maybe one a little more dense, depending on when we get off earth.  But long term?  Hang out, orbit the galaxy for a few Gyear, maybe do another planet or star someday.
ME: So, tell us about your life.
He-p: Well, we we’re all born 13 Gyear ago,
He-n: just like everyone else
He-p: well, us nucleons, yes, but fluffy ‘nuclei suspended in electrons’ human over there,
He-n: oh, never mind, no offence intended,
He-p: yes, well.
ME: …


Once upon a time, a large star exploded.

Well, sorry, that’s it for this evening, and for this post.  Comments encouraged.

OLPC Repo Watch

2008 November 17, Monday

OLPC-related projects keep their source code in a variety of places. is an exploratory attempt to create a combined list of OLPC-related project repositories.

Thus making it easier to see people’s work.

The list includes all projects on and, and projects found searching for “olpc” on,,, and  Also activity pages on

I would appreciate feedback on whether you find it useful.

Numeracy software – some ideas

2008 January 30, Wednesday

Vision for a numeracy activity (Activity is OLPC-jargon for a software program) is my rough sketch of a numerate educational desktop.

Simplified OLPC laptop emulation on linux

2008 January 27, Sunday

A new version of xo-qemu is available.

xo-qemu is a script for downloading, managing, and running OLPC QEMU disk images on linux.

The One Laptop Per Child (OLPC)<> project creates a linux distribution for its laptop. It is released as numbered builds (ie, “versions”), in several streams (eg, separate streams for developers and end users). These builds are available in several forms, one of which is a disk image that can be run on the QEMU virtual machine. This script makes it easier to obtain, manage, alter, and run these disk images on linux. It provides virtual, slightly broken, emulated OLPC XO laptops.

olpc_xo_qemu-0.006 is a bugfix release.
It should work with all the builds 0.005 did, plus current joyrides.

This is alpha quality software. It is unclear how many people, if any, are using it. Please drop me a note if you are. Thanks.


My thanks to Eduardo Silva (edsiper) and his XO_Monitor for the FUSE filesystem mounting.

Example use:
$ xo-qemu –report
$ xo-qemu –new-user
$ mkdir builds laptops
$ xo-qemu –get-build joyride latest builds/
$ xo-qemu –make-laptop laptops/one `xo-qemu –get-build joyride latest builds/ |tail -1`
$ laptops/one/xo on
$ laptops/one/xo xephyr on
$ laptops/one/xo xephyr off
$ laptops/one/xo ssh ls -a
$ laptops/one/xo do import -window root screenshot.png
$ laptops/one/xo mount
$ ls -a laptops/one/root laptops/one/olpc
$ laptops/one/xo mount -u
$ xo-qemu –help

A new blog

2007 November 24, Saturday

Hi, I’m Mitchell N Charity, an ex-MIT software engineer.

This blog is envisioned as a few posts a month on a range of topics, including One Laptop Per Child, programming languages (especially Perl 6 and Ruby), and science education (especially rough quantitative reasoning).

This is my first public blog, and an experiment. Does blogging help fill the gaps between wikis, web sites, and mailing lists? Do I enjoy and keep it active? Does it find readers and generate discussion?

The name “Bootstrap Exercises” comes from computing. “Bootstrapping” is creating a not-yet-existant system, using (often) more limited existant systems as tools. Often the effort and pain of creation would be much less if the new system could be fully used as tool in its own creation. Eg, “if someone had ever done this before, it would be much easy for us to do now”. While you obviously can’t fully use something until it exists, often parts of it can be used earlier. The challenge and art of a bootstrap, is to incrementally orchestrate parts and placeholders and jigs, and tools partially working and variously broken, to craft a minimally costly development path to the desired system. And it’s a process which occurs with remarkable similarity in many fields of engineering, education, and society. Civilization is a bootstrap exercise. It’s a process usually frustrating, often tragic and joyful. And one dear to my heart. Thus the blog name.