Month: May 2014

Good News, Everyone!Good News, Everyone!

“Good news everyone! I’m sending you on an extremely controversial mission!”
―Professor Hugo Farnsworth, “The Birdbot of Ice-Catraz”, Futurama

It’s graduation season, and I’m in post-production now after playing the role of Audience Member in three recent productions of Commencement 2014. At UC Berkeley’s Department of Earth and Planetary Sciences, Professor Tanya Atwater of UC Santa Barbara provided the keynote address. She was excited to report on her experience as part of the team writing the new science standards.  For members of the EPS department, the “good news” is that the new standards specifically include Earth & Space Science as one of four core disciplines.  Advocates of coding-in-every-classroom will also be happy that one of the four is “Engineering, Technology, and Applications”, though they may be disappointed to find that coding is not all there is to technology.

However, as Professor Atwater pointed out, this is a creation devised by a committee, and a large one at that.  These standards are huge, complex, and demanding.  I won’t be surprised if primary teachers throw up their hands and say “Heck, the old Science Framework was complicated enough!  We’re going back to literature, thanks a lot.” I had a peek at a few pages–the new standard can be surveyed in an interactively, online.  For instance, if you select Grade 1 and Physical Sciences, you are taken to a page entitled Waves and Their Applications in Technologies for Information Transfer

If that’s not enough to send your primary-grade teacher screaming to the arts-and-crafts cupboard, he/she is then presented with a grid of expectations about what first-graders should be able to understand and demonstrate about waves, from sound waves to light waves.  I can tell by the “clarifying statements” and all the hyperlinks to definitions for everything from the requirement that students “Make observations to construct an evidence-based account” to explaining that you use “Cause and Effect” to show that when the lights are off you can’t see objects.  Well, says the gamer kid, what if I have my night-vision goggles on? 

Meanwhile, the teacher is supposed to be tracing all the Common-Core standards links and the cross-discipline values obtained.  As an engineer, I find that sort of thing daunting, while I suspect most trained teachers find those elements-links an easy yawn–it’s the demand they convey science skills to kids at what seems to be a very sophisticated level that presents a barrier.   Remember, it’s unusual for an elementary-school teacher to enter the field with more than a bare minimum of science or technology training.

Not good news?  Well, it may be good news for some students currently graduating in the sciences–the new standards create a market for teachers who have science toolkits ready to hand.   And if states are not too heavy-handed in adopting these standards, the NGSS provides tons of leeway in the actual curriculum developed and in both straight-up statements and in the subtext of the descriptive matter the NGSS strongly urges the use of hands-on, experiential learning techniques.  That’s good, especially in elementary school, because hands-on activities are the best, overall, at evoking those Aha! moments that make science exciting.  What the scientists working on that committee were most excited about was the prospect of bringing that thrill to more students, not only to attract some to actually becoming scientists or engineers but also to allow those following other paths to understand what motivates the ones who do follow the siren song of science.

For example, if you jumped to Professor Atwater’s page, you’d have read her non-committee-developed description of her motivations to teach and her love for science, “In lecture, I used to think I wasn’t a good scientist if I admitted my passion. No more. In the last few years I have adopted a style of expressing my delight along with sharing why I’m delighted – the intricate order and sense (and, sometimes, irony) of how things work – wonderful!”

One of my best experiences during Commencement Week was talking about education with a Kindergarten teacher who was struggling with making sure his (yeah, don’t go sexist on me–men can so teach kindergarten) students each got the attention they needed, despite a class size of more than thirty, in a year when he had no parent volunteers to help out.  And though he was looking forward to summer vacation, he was the most interested to hear about some of my “Messy Monday” science experiences.   As a result, I’m determined that the next couple of activities I put up here under the “Messy Monday” label will be ones targeted to the K-2 crowd.

So, well, the new science standards, if you can get past the committee-style presentation, could be turned into good news.   Let’s get kids doing the kind of science that comes naturally to them:  trying things out, making mistakes, watching what happens.  Let’s help them break free of seeing what they expect to see–it’s those wow moments of unexpectedness that give doing science that endorphin rush.  It’s when the comet is chasing its tail on its way out of the inner Solar System or a water jet sprays farther than you guessed or you suddenly realize that a rainbow isn’t part of a prism or a raincloud or even a soap bubble–it’s the light itself that makes the rainbow.



Moon & Spica

Eclipsed Moon With Spica



A few weeks ago, we had a beautiful lunar eclipse visible in North America.  It was well worth sitting out to watch the Earth’s shadow advance until the Moon was completely covered and glowing with a warm red hue, then retreat until the Moon shone bright once again.  Here is a combination of a poem written for a workshop many years back, inspired by another lunar eclipse, with a few photos from this year’s event.  Multitudes of astrophotographers caught fine images of that eclipse.  This time, my equipment on hand was my hardy little point-and-shoot Lumix, which yielded many images suitable for artistic manipulation, especially with effects added by the drifting fog that interrupted our clear view.  Mars was in view as well, so I’ll include one image with Mars.  Can you spot it?

I watch the Mother walk my night,

spreading her darkness through my shadows.

She turns to me as the night turns, and I watch, I gaze,

rapt in the music of her light.


2014 April 14-15 Total Lunar Eclipse
Wrapped round and full in the stillness of this, my night,

she draws in light and darkness from the sky,

and sets them in my hands and at my feet,

until the whole land is an image of sky,

until I am full, full round and whole,

wholly wrapped in the music within my darkness.


Fog Rainbows
She waxes as the night wanes, and I gaze, gaze,

until I dream I am a fish which has never before known water,

and now, for the first time, breathes …

until I dream I am a child who has never known her name,

and now, for the first time, dreams …


Artist's Impression
dreams she stands with a woman, a stranger,

in a land which bears an image of sky.

The other, the stranger, is silent beside her,

while she speaks to the mother as a favored daughter.

As she speaks, I give back through my hands

the light and darkness which is the sky

until the land rests again beneath my shadows,

until the child knows me for herself.


Floating in the Ether
Even as we greet and join each other,

the Mother steps over the edge of the world.

Even as the stars first claim the sky,

I breathe the mist of my first morning.


Bloodshed Moon


The Eight-Sentence ParagraphThe Eight-Sentence Paragraph

Apparently there is some sort of internet rule that all pages must have pictures. Even tweets, which were supposed to be the haiku of the internet now have to have photos attached.  Sorry, but this post has no pictures.  Wouldn’t be appropriate, as you’ll see.  Please don’t report me to the internet police.  Oh, I’ll put in some links.  Will that help?

This is a story I wrote for my son after a school lesson like to killed his interest in writing, fiction or non-fiction.  Given that he’s going to be spending the next semester writing a senior thesis in biology at UC Berkeley, I feel it’s only fair to take credit for saving his writer’s mind back in fifth grade.  Of course, his favorite writer is Charles Darwin.




Thomasina Keck sighed, looking out on the chaos of her fifth-grade class. There were too many questioners in this year’s group, too many boys who objected when girls gave them the business, too many girls who preferred to talk in class. Her hopes of getting thirty decent essays on her desk by the end of the month were fading fast. And the stupid standardized tests were scheduled for the week after that. No one would be paying attention to anything that week; the stress of Test Week wiped out everybody, including the teachers.

Mark Peterson sighed, squeezing into the back-corner desk surrounded by chattery girls. An aura of doom hung over his head. Sooner or later today, he knew, he would tell Maura or Sue to knock it off, and his name would be up there on the board. “How can I help it if the only one she hears is me?” he had moaned to his best friend Drew only yesterday.

It didn’t help that Sue kept track of his Detention Count, as sort of an anti-charitable act. She giggled as he slid into his seat. “One more time, Markie-Mark,” she said, just loud enough for Maura to hear. Eight times up on the board, and it was Detention. Mark gritted his teeth and tried to focus on laying out paper and pencils from his binder. The last thing he wanted to do this afternoon was sit in the office writing about how he could have been a better student.

Mark tipped his chair back, so he could see around Sue, and made a face at his best friend, Drew. The Evil Ms. Keck had put the friends as far away as possible. Drew pulled a face of his own, his trademarked Sick Fish impression, made their secret sign for “crazy”, and pointed dramatically to the front of the room.

When he looked, Mark’s heart sank even lower. Ms. Keck had written across the board “The Eight-Sentence Paragraph.” Oh, no. Writing time. Dimly, Mark remembered a time not so long ago, in third grade, when writing had been his favorite subject. Fourth grade had been a bummer. Not only had he and Drew been stuck in separate classrooms, but Drew got Ms. Houlihan, the teacher who had all her kids write their own books as a class project. He, Mark, got stuck with Mr. Black, whose idea of language arts was an endless series of grammar worksheets, word finds, and spelling words written three times each. Mark had only survived by writing in his journal every day while Mr. Black went through the worksheets one question at a time every morning.

Now, here was this Ms. Keck, trying to teach him, Mark, how to write a paragraph! Mark grunted, picked up his pencil, and laboriously wrote out the now-familiar list:

  1. Introduction.
  2. Reason.
  3. Explain.
  4. Another reason.
  5. Explain that reason.
  6. Another reason.
  7. Explain that reason.
  8. Conclusion.

Then Mark wrote:

Eight-sentence paragraphs are pointless. They are really dumb. It is a way for stupid people to pretend they are writing paragraphs. They are really fake. Real books have paragraphs with lots of different numbers of sentences. They are boring. No one wants to read the same thing over and over in one paragraph. Only really bogus brainless dweebs write eight-sentence paragraphs.

Sue was leaning over. She was reading his paper. That made Mark mad. He glared at her, just barely keeping his mouth shut. But she just made the peace sign at him. What a bogus brainless dweeb! he thought.

Up at the front of the room, her nose twitching with the smell of the dry-erase marker, Ms. Keck tried to pretend she didn’t see the little exchange going on in the far corner. She knew Mark was in a bad spot, but she just had to have someone between those two jaw-waggers, Maura and Sue. This month it was Mark’s turn. He deserved a little slack. So she pretended not to notice how he’d scooted his chair back so he could read the book on his lap.

“All right, now, class,” she said, trying to inject a little energy into her voice. “Can anyone remember how we build our eight-sentence paragraph?” After eight weeks, you’d think they’d have it down. A few kids raised their hands.

“Alyssa.” That girl usually had an answer.

“Can I go to the bathroom?”

Ms. Keck felt like whapping herself in the head with the dry-erase eraser. That’s just what she needed—a procession of girls tripping off to the washroom.

“Alyssa, surely you can wait until recess. You just came in from lunch.”

“But I really really really have to go.”

All right then. She didn’t want to play the ogress today. But she could use her teacher power. Alyssa’s pal Katie was already standing up. The bathroom, like everything else in this cockamamie California school was reached from outside the building. So school rules were that all bathroom trips required buddies. Ms. Keck pointed to the big girl at the back of the room.

“Antoinette,” Ms. Keck called out, and the oversized girl in the back row jerked her head up from a page of doodles. “Please go with Alyssa.” Katie plopped back into her seat with a dark look.

Mark, despite his surreptitious reading, followed this little battle with some pleasure. Katie and Alyssa were the official class Popular Girls. They were fond of hanging out in the corner of the playground and calling the boys names when Yard Duty wasn’t listening. Some of the names were so rude that Mark wasn’t entirely sure what they meant.

But The Evil Ms. K. did not let her victory distract her from the task at hand. She turned immediately back to The Eight-Sentence Paragraph. Mark closed his eyes and felt a familiar feeling rush through him. First he felt hot, then cold, then all fluttery. He had a funny feeling recess would be bad today. It was always bad when he was feeling angry like this.

He opened his eyes and stared down at his book. It was the library’s copy of The Prince and the Pauper. Ms. Keck’s classroom copy was some bland kiddie version. It left out all the good stuff, like just exactly how mean and nasty the pauper’s dad was. He scanned over the two pages that were visible. Not one paragraph had eight sentences. He turned the page. No eight-sentence paragraphs here, either.

“I bet,” he thought, “there isn’t one eight-sentence paragraph in this whole dang book. Someone should show Ms. Keck.” And although he didn’t believe in wishing any more, Mark silently wished with all his heart that someone big and impressive and really convincing would really truly show Ms. Keck a thing or two about her stupid eight-sentence paragraphs.

Suddenly, he was aware that a large hand, a grown man’s hand, was resting on his desk. Half of his official eight-sentence paragraph was covered by the hand. It was rough, a little wrinkled, with short fingernails. He could see flecks of dirt under two of the fingernails.

“What’cha reading there, boy?” a low, masculine voice said behind him. Mark could feel all the hair on the back of his neck stand right up on end, as if he were a cat. Numb with surprise, he simply lifted up the book so the person behind him could see the cover.

A hand to match the first appeared from behind his head and picked up the book. The man chuckled. It was a pleased, contented chuckle, the kind you hear when your dad catches you picking up your room before he’s told you to.

“That’s not the best one. Written to make a point, as I recall, not just to tell the story.”

“Oh, but I really like it. And it doesn’t go all gloomy in the end, like Connecticut Yankee does.” Drawn into an argument, his favorite kind of conversation, Mark forgot he had the creeps and twisted around to look at the visitor.

The man was kind of tall. He had fluffy salt-and-pepper hair and a funny puffy mustache. He smelled strongly of tobacco smoke, which was kind of unpleasant but not quite as bad as the smell of Mark’s aunt’s cigarettes.

“Excuse me?” Ms. Keck’s voice struck its coldest, firmest level. “And you would be…?”

“I would be, madam, that most unwelcome of creatures, the unexpected visitor,” the stranger answered with a cheerful grin. His long, gangly legs carried him up to the front of the room in a few relaxed strides. “I’ll not be any bother. I’ll just set myself in the corner here. You just go on with what you were doing.”

The visitor wasn’t exactly in the corner when he said this. And it was hard to believe that Ms. Keck would not be bothered. He had planted himself at her desk. What’s more, he leaned back in her chair and parked his feet on the corner of the desk, right next to her Styrofoam mug full of Sharpie markers.

The class could not help itself. It gasped. It was a very soft, collective ah! And this meant Ms. Keck had to stifle her urgent need to tell this fellow off. By no means was she going to unbottle the energy of this class by giving any indication that she was bothered. She forced a smile.

“Welcome to our classroom, Mr. — ?” And she made it a pointed, direct question.

“Clemens, ma’am. That would be Mr. Clemens. I’m visiting from Connecticut, now, but I spent some time out here in California some time back, when I was in newspapers.”

“Is that so? Well, Mr. Clemends, if you can bear with us, we are reviewing our latest lesson in writing. Hassan, would you tell our guest what we have been studying?”

Hassan was usually quick off the mark. He was a short-term student, the son of a Nigerian engineer who had been brought over to the states for some big project up at IBM. Hassan had previously attended rather upscale private schools. But today, the boy was too dazzled by the tooled cowboy boots resting six feet to his left. He only turned his head slowly back to the front of the room and said, totally Americanized, “Huh?”

Corrina raised her hand and waved it vigorously. Having won the right to speak, she rattled off, “We’ve been studying paragraphs, because all our old essays are all just one big paragraph and you told us that was bad and so we have to learn to write paragraphs and the way to write a paragraph is to write eight sentences.”

“Very good, Corrina,” said Ms. Keck, actually allowing herself to feel a little pleased that the girl seemed actually to have absorbed the lesson.

The visitor shifted, making the old chair squeak. When the students’ heads swiveled his way, he asked, “And how long might those sentences be?”

“Oooh! Oooh!” It was Mayella’s turn to reach for the ceiling. “I know!”

“All right, May,” Ms. Keck said. “How long should each sentence be?”

“Short and sweet!” So that was two correct answers in a row. Ms. Keck felt a warm happy glow. Maybe things were going all right after all.

“Wonderful!” she said. “Let’s just go round the group and see if we remember our sequence. Neal, why don’t you start us off?”

Neal, a thin nervous boy who looked like he ought to be wearing glasses, coughed out, “Introduction.” Ms. Keck turned and swiftly wrote the word next to the number “1” she had ready on the board.

Oh, she was in her element now. Without looking over her shoulder, she called out the names and wrote their answers.

“Elena, what’s sentence number two?”

“Um, a reason?”

“Yes. Sasha?”


And so on through Carmelita, Edgar, Isaiah, Adnan, Paul, and Nick, until Mark could look up at the board and see his list replicated in orange marker. Ms. Keck finished her list with a flourish and turned with a smile.

“There now! I think you have it! Very good, class!”

But then there was a weird noise over at Ms. Keck’s desk, and everyone looked away from the teacher. The visitor was leaning over, tapping something on his boot. That was what made the strange thocking noise. Mark leaned over his desk to see past Sue’s bangs. It was a pipe. The guy had a pipe in school. Did he have the nerve to light it up?

But Mr. Clemens just tucked the empty pipe between his teeth. He may have had the nerve, Mark decided, but he just plain wasn’t that rude. He had claimed everyone’s attention, though. And once he knew all eyes were turned his way, the tall man stood up, grasped the edges of his vest with those big, gnarly hands, and said, “Poppycock.”

Ms. Keck made a squeaky noise. Then she swallowed and said, very coldly and politely, “I beg your pardon, sir?” She stood up very straight and stiff, somehow managing to be looking down at him, even though she barely topped five foot three.

“I said, ‘Poppycock’,” Mr. Clemens repeated, extracting the pipe from his teeth and tucking it into the pocket of his vest. “By which I mean, floptwaddle. Malarkey. Or, as the English fops so elegantly put it, stuff and nonsense.”

Ms. Keck, you had to give her credit for that, stood her ground. “And I said, ‘I beg your pardon?’, meaning ‘Have you forgotten that I am the teacher in this room?’”

But the big man was only revving up. “That’s confoundedly easy to forget, madam, when I hear you spouting such a load of tomfoolery. What in the blazes do you mean to accomplish here? The single-handed degradation of the art of American letters?” And he strode right up to the front of the room, picked up the eraser, and wiped The Eight Sentence Paragraph clean out of existence. Three of the boys at the back of the room actually burst into applause.

Ms. Keck stared at the invader. She honestly didn’t know what to do. She couldn’t leave the class to get help, not with a stranger in the room. Shouting for help could not be effectual, not in her hard-won self-contained classroom at the far end of the building.

Besides, what would she say? “This terrible man just erased my whiteboard”? She would be the butt of staff room humor for weeks to come. Nothing for it but a fight to the bitter end. She squared her shoulders, and stepped right up to the smart-alecky so-called visitor.

“Mister Clemends. You seem to have forgotten your promise. Observing classrooms is permitted. Interfering in lessons is not.” She glared up at him. He smiled down at her, with a twinkle of laughter in his eye.

“Very well then, madam. How about you provide some evidence of this spider-shaped paragraph, eh? You there, boy,” Clemens said, crooking a finger at Mark. “Let’s have a look through that book you have there.”

Mark passed the book forward, suddenly anxious that his sneak reading was now front-and-center with Ms. Keck. The visitor would be gone by the end of the day, for sure, well before she handed out detention notices.

Mr. Clemens took the book into his big hands gently, almost affectionately. “Says here,” he said with evident satisfaction, “that this book is one of the great classics of American literature.” And he slapped the slim hardcover right into Ms. Keck’s hand. “I dare you. Count the sentences in those paragraphs. Mark my words. I wager that you’ll not find even one, but even if you do, it will not read anything like this…” and he proceeded to quote Mark’s “bogus dweeb” paragraph, verbatim. Mark turned bright pink. He could feel it, like a fever. For once, he was relieved to be at the back of the room, with only Sue close enough to see. And her eyes were riveted to the front of the room.

But Ms. Keck was not giving up. “The children are learning to write essays, not fiction, sir. And you must realize that they are just beginning to learn about the structure of writing. The eight-sentence structure teaches children to organize their thoughts as they write and to justify the arguments they present in an essay.”

“Just beginning?” Mr. Clemens cast a skeptical eye around the room. “These great big boys and girls are only just beginning to write? What kind of a sorry excuse for a school is this?”

“A school with a well-ordered curriculum, Mr. Clemends. Now, if you don’t mind, we have very little time to complete our lesson today.” Ms. Keck felt herself in command again. She stepped back and glanced significantly toward the door, giving the ignorant interloper a fair opportunity to leave the room.

From his corner seat, Mark actually had a good angle on the action. He could see Ms. Keck with her head high, her chin in that commanding attitude that usually presaged a Name on the Board. But he could also see the bright gleam in Mr. Clemens eye as he took two steps towards the door, and then turned sharply, taking up position at the left side of the whiteboard. Once more, he had captured the attention of the class. Ms. Keck was totally upstaged.

Mr. Clemens reached down and picked up a marker, and pointed it at Mark.

“You there, boy. What’s your name?”

“Er…” Mark took a second to glance over at Ms. Keck. She was turning pink, too, but slowly. Would she explode? No one had ever seen Ms. Keck actually lose her temper. But then Mark realized that for now, he didn’t care about whether the teacher would break down and have a tantrum. He wanted to hear what this Mr. Clemens had to say, if only because the mysterious guy liked his book. “I’m Mark Peterson.”

“Good. Now, then, Mr. Peterson.” No one had ever called Mark “Mister” before. “Why don’t you stand up, so the other pupils can hear you? That’s better.” Mark felt a little funny standing up in the corner with everyone’s eyes flicking back and forth from him to Mr. Clemens. “Now, let’s hear from you. What’s a paragraph?”

“Um.” Mark felt desperate. Suddenly, he was sure he’d forgotten everything he ever knew. All that actually came to mind was Ms. Keck’s eight-sentence flapdoodle.

“Come along, come along. Madam, do these children also not know how to speak up?”

That helped Mark, because it revved up a little of his mad. Of course he knew how to speak up. “A paragraph,” he said, fumbling around in his head for those slippery words, “is when you have a lot to say on an idea and it just doesn’t fit into one sentence.” And he stopped to think a little more. What was even more amazing was that no one interrupted him. “But it could still be one sentence, if it has an idea that doesn’t fit with the ones around it. Or it could be really really long, like maybe a description. Or …”and his eye caught the poster of the Declaration of Independence at the far side of the room. “Or a list. Like a long series of …of…trials and usurpations.”

Mr. Clemens favored him with a grin, and turned that grin full force on Ms. Keck. It actually made her step back a little. “You see, madam? These children know what a paragraph is. Don’t you, boys and girls?” He pointed to Charlie, who sat smack in the middle of the room, because Ms. Keck could be sure he’d never say anything to anybody. “Why bother using paragraphs? Speak up, boy.”

And Charlie did better than that. He stood up, like he’d seen Mark do, and then he spoke up. Mark saw Ms. Keck’s mouth actually flap open in surprise. “Well, it would be a mess, wouldn’t it, if all the words just kept going and going? It would give you a headache.”

Then Maura raised her hand. The big man pointed and she stood up. “When the paragraphs are big, you have to read slower and when they’re short, you read faster. Do writers do that on purpose?”

“Aha!” laughed Mr. Clemens. “You have caught us out! See here, madam, you have children here who actually read books!”

Maura sat down, but she also twisted around to look back at Sue. This is so cool! she whispered.

And then Alyssa and Antoinette appeared in the door. Ms. Keck took her chance and marched across the room to meet them. “Girls,” she said, keeping her voice level and clear. “Please run up to the office for me and ask Mr. Cochrane to come over here.”   The pair were more than willing to skip class a little longer, not having been entranced by the Unwelcome Visitor.

Ms. Keck had every right to be in a panic. She had every justification to be calling in the heavy artillery. But as she stood there in the doorway, watching her students take turns standing up and speaking up, she took the time to give herself three nerve-calming breaths. No sense wasting all those hours in yoga class. She ran her eyes over the border strip on her whiteboard, which read, “Every new day is an opportunity, not a challenge.” It just one of those Classroom Inspiration decorations that ate into her meager salary. But maybe, just maybe, there was a grain of truth in that fatuous message.

Very calmly, Thomasina Keck walked up to her whiteboard. Mr. Clemends was still holding the orange marker, so she picked up the green one. She took a moment to think, and to listen, and then she began to write.

Mark’s brain had been working on overdrive ever since Mr. Clemends had answered Maura’s question. He had said “you caught us.” This guy was a writer, a real writer. Who in the class knew a real writer? Was someone’s Mom or Dad just as sick of the Eight-Sentence Paragraph as all the kids were? Did he know of any writers named Clemens? Had they heard him right?

Mark flipped over his paper and started scribbling down the names of writers: LeGuin, Konigsberg, Pilkey, L’Engle, Shakespeare, Sachar, Tolkein. No, too many women. Too many dead guys. Wait, he told himself, the bookshelf is right here. So he shifted his chair just enough to get a clear angle on the spines of the books in Ms. Keck’s classroom library. It didn’t take long.

Mark felt like his arm was going to pop out of its socket, he was holding it up so high. But Maura and Eleanor also had their hands up, and Eleanor was waving hers back and forth eagerly.

Suddenly, Mark realized that Ms. Keck was at the board, writing away feverishly in bright green marker. Mr. Clemens and she seemed to be working together, as if he were in fact an invited visitor. Every time a student spoke up, Ms. Keck scribbled something new on the board.

Mark couldn’t help being interested. He switched to holding up his right arm so he could write. Below the crossed-off names on his paper, he tried to copy what Ms. Keck was drawing. Somehow, it just looked cool, way cooler than the old eight-sentence list.

Finally, Ms. Keck tapped Mr. Clemens on the shoulder and spoke very quickly in a low voice that nobody else could hear. He pulled the cap off the orange marker, wrinkled his nose at the smell of the ink, and tested it on the board. Satisfied with the stinky tool, he wrote across the top of Ms. Keck’s green writings “The Authentic Paragraph”. Both adults stood back to admire the result. They both seemed happy. It even looked as though the Evil Ms. Keck was starting to smile.

When they turned back to face the class together, Mr. Clemens immediately pointed to Mark and said, “All right, Mr. Peterson. You have something more to say?”

Mark had nearly forgotten he had his hand up. But what he had to say was still on the tip of his tongue. “You’re the writer, aren’t you? Andrew Clements?” And he was careful to pronounce the t right before the s. “I really like your books. I read Frindle back in third grade and Drew and I made our own newspaper last summer, like in The Landry News, only we didn’t do it in school and we didn’t get famous, or even in trouble either.”

The visitor managed to look surprised, but he didn’t say anything. He just cleared his throat.

Ms. Keck whirled back around to stare at him. “Oh! I had no idea! And to think we have all your books in our class library! Why didn’t the PTA tell me you were coming?”

And just at that moment, Mr. Cochrane appeared at the door. He paused for an instant to assume what Ms. Keck thought of as his Aura of Mastery, that mixture of pose, gesture, and superior eye contact that declared him top dog in his little territory. Then he sailed into the room with a cheery “Good morning, fifth-graders!”, Alyssa and Antoinette marching behind him like a pair of half-size bodyguards.

One sharp look from Ms. Keck, and the girls fled to their seats. A word from Katie Lynn and Alyssa was back on her feet squealing “Oh, Mr. Clements! Can I have your autograph!”

Ms. Keck met Mr. Cochrane halfway. “Is there a problem here?” he intoned quietly, favoring the class with a deceptively cheerful smile.

By now, Ms. Keck could hardly remember why she had thought it necessary to send for the principal. “Not at all, Steve,” she said soothingly. “It’s just that we had an unexpected visitor in class today, and I knew you would want to be in on the excitement. Did the PTA President fill you in already?”

Mark had his eyes glued to the teacher and the principal. From here, it actually looked as though Ms. Keck was heading him off. Then a wave of oohs and aahs from the girls in front of him alerted Mark to something new. Mr. Clements was headed his way.

When he stopped next to Mark’s desk and Mark looked up at him, the author seemed even taller than he had up at the front of the class, towering over little Ms. Keck. He had Mark’s book.

“Glad you enjoyed the book, son,” he said. “Do me a favor. Try out my favorites. There’s a lot of Tom Canty in that old Huck Finn.”

Mark took the book back almost reluctantly. It seemed to spell an end to this adventure. “Okay,” he said. “I’ll check out Tom Sawyer. Mom says I should wait some before I read the big one.”

He was rewarded with one last deep chuckle. “Don’t wait too long. Huck’s not much older than you are, leastways with his life frozen in those books.” And he squeezed Mark’s shoulder as he moved on behind the row of desks.

“Children, can I have eyes front now, please?” came Ms. Keck’s commanding voice once more. Mark jerked his eyes up from the cover of The Prince and the Pauper to see the teacher pointing at a bunch of squiggles on the whiteboard. “Let’s show Mr. Cochrane what our visitor helped us work out today. Mr. Clements, would you like to…? Mr. Clements?”

There was no one in the classroom but twenty-seven students, one teacher, and one principal.

Brianna leapt from her desk and leaned out the door. “He’s gone!” she gasped. “Where did he go?”

“Now I’ll never get my autograph!” Alyssa whined.

Mark leaned back and tried to signal Drew. Mr. Clements had been heading in that direction. He must have slipped past Drew and out the door while Ms. Keck was getting fired up to show him off. Who knew a guy like that would be too shy to talk to the principal?

Up in the front of the room, Ms. Keck found herself still on balance, going with the flow. She only had to raise her voice just slightly, injecting a bit of calm and certainty. “Mr. Clements had to leave,” she said. “Our lesson did, after all, run much later than planned. But we still have our results, don’t we? Let’s take these last few minutes before math time to share them with Mr. Cochrane.”

The new paragraph-teaching approach was a huge hit. Steve Cochrane bought into it primarily because he was there when it was invented, and he used it to great effect in his political machinations up at the District Office. The kids bought into it because they, after all, had invented it. The teachers, as usual, were willing to try anything that worked.

It was Drew who named it, Mark Peterson’s buddy, the one kid who hadn’t actually had much to say that day. He’d sat there in the back of the room, stewing over all the attention “Mr. Peterson” was getting. And so he was the first one to notice the pattern Ms. Keck’s scribbles had made.

The biggest scribble said simply, “One Main Idea”. She’d circled it, so it made a big blob in the middle of the board. Then she had “Topic Sentence” in parentheses right next to the blob. The parentheses were big and swoopy, nearly meeting at the top and bottom. If you squinted, that made a blob with a head. So that made the New Improved Paragraph into some kind of creature. It was a live animal, crawling across the board.

It looked like it was crawling because there were all these words written as if they were springing out of the sides of the blob. Some made sense from what Drew remembered the kids saying in class, like “Details” and “Dialogue”.   Others made sense later, when they all copied the creature into their language arts notebooks and Ms. Keck explained why she chose certain words. For instance, “Pacing” had to do with Maura’s question about whether authors used paragraph length to get readers to slow down or speed up.

But long before he had the meaning of all those words clear, the shape of the whole thing was obvious to Drew. It was a spider, just like Mr. Clements had called Ms. Keck’s Eight-Sentence Paragraph. And he couldn’t help adding his own little observation, when he put in his suggestion for the Official Name, “It’s not really all that different from what Ms. Keck was trying to get us to do all along. The one big idea is the introduction and conclusion and all the other stuff is details and explanations. They just don’t necessarily add up to eight sentences every time.”

So Spider Paragraphs they were, all the rest of that year and for the rest of the years that Ms. Keck taught fifth grade. And she never tired of pointing out Andrew Clements’ books on her shelves at the back of the room. There were a few times that she wondered if it had really happened, such as the time she clipped a newspaper feature about the author.   He looked rather different than he had that day in class.

But Drew earned several shoulder-punches at afternoon recess that day, for sucking-up to the teacher. Only his best buddy gave him a break. Mark dragged him free of the guys and over to their personal hideout, in the shade of the bushes behind the backstop.

“Just look at this,” he said, urgently, pushing a hardcover book into Drew’s hands.

“What?” Drew protested. “I’m not on detention. I don’t have to read during recess!”

“No, no. Look here.” And Mark was eagerly flipping the pages at the front of the book, just as far as the title page.

“Oh, man,” Drew frowned. “You are in for it. This page is scribbled all over. You know what they make your parents pay for a damaged book?”

“Come on, come on,” Mark said impatiently. He bit his lip, he was so excited. He couldn’t stand it much longer. Drew was his best friend, the only one he could possibly trust with this. And he had to show somebody. “Just read it, will you?”

And Drew read it. The scribbling was actually pretty tidy for cursive writing. It looked smooth and even, as if it were done by someone who actually wrote by hand more often than by computer.

And he read it again. And again. Why was the last bit in quotes like that? Oh, yeah. Oh.

Mark watched him, tasting the metallic saltiness of the blood from his lip. Did Drew get it? Did he see?

“Oh, man,” said Drew. “Listen, I’ll help you pay the fine. No way do you want this book to ever go back to the library. Wow.” And he looked Mark in the eye. “Mind if I borrow it, sometimes, just to look at it?”

“Yeah, sure. Just don’t ever tell. Swear?”

“Swear.” And Drew handed back the precious book, with the long inscription on the title page. Mark knew this was one book he’d be keeping forever. While the end of recess bell squealed outside the hideout, he turned once more to read that loopy, elegant autograph:

To my dear friend and colleague,

Mark Peterson,

all the best of luck in the future.

Samuel L. Clemens

“Mark Twain”


Chasing Comets

Chasing Comets: Supplies & ResourcesChasing Comets: Supplies & Resources

Supplies and Materials

Below, you’ll find a handy supply document you can download, with shopping lists for small and large groups and a range of cost estimates, depending on how much of the supplies you can acquire from available supplies or donations by participants.   With a minimal outlay, you and your group can experience being comet chasers–observers of comets.

Basically, you need a bunch of badminton birdies for your comet heads—keep in mind you don’t need performance-grade shuttlecocks or even new ones. If your high school has a badminton team, they will have worn-out birdies you can take off their hands.   A grungy, beat-up birdie makes a more realistic comet head.

Chasing Comets

Birdies for Comets

And you need a bunch of ribbon—curling ribbon for the comet tails. The supply sheet estimates ribbon packages at around $8, but if you look at this photo, you’ll see the last time I bought supplies, it was out of the clearance bin at $2. And if you can get one in five of your participants to bring in a roll to share, it won’t cost you a dime.

Chasing Comets

Zoom Out–Yes! Here’s All You Need To Make Comets

The one oddball item is that tulle fabric ribbon for the big comet. This you might have a hard time finding in your junk drawer unless you’ve been helping a bride make wedding tchochkes. But for $10 you can buy enough to make three huge comets. Cut five-yard lengths and tie one end of each to a vane of a single birdie, allowing a few inches of extra length to fan out as the comet’s “coma”. Tulle scrunches up easily, so even a six-inch-wide ribbon will feed through the holes between the birdie’s vanes.

Chasing Comets

Detail–How To Tie Fabric Tails

You should be able to borrow a portable fan and a playground or soccer ball. If you can’t, it will take a roughly $25 expenditure to get those items in stock—a cost you can recoup in part by either donating it to the group you’re working with or simply deducting the expense as part of your cost of volunteering.

And it is presumed you can find a pencil, which makes holding the small model a little easier when you’re doing the demo with the fan;  here’s the trick for hooking the pencil to the comet head:

Chasing Comets

Holder For Fan Experiment

Depending on how good you are at scrounging supplies and locating soccer balls, your costs will range from $10 to $85 for typical group sizes.   The spreadsheet I use has a calculation column to adjust the requirements list for other class sizes  So, if you want a copy of this  fully-functional workbook, “like” the Facebook page & I’ll send you one via a Facebook “message”. (You can also try emailing me through the “contacts” page here, but you’ll get a faster response on FB.)  Your FB contact will be used for nothing other than sending you a file and boosting the “likes”-count on my page.  [Insert maniacal laughter, if desired.]

Meanwhile, you can get the static workbook as a pdf right away:

Just Supplies Chasing Comets


Resources and References

Now that you are all excited about comets, here are some fun places to go where you can find more cometary material:

A lovely one-page summary from the Spaceguard Program (sponsored by the European Space Agency) gives a clear description of comet tail structure and dynamics, including a neat animation of what both tails look like as the comet proceeds around the sun. The ion tail streams straight back, while the dust tail is curved a bit as the particles within the dust tail blend movement due to their individual orbits about the sun and the forces of the radiation pressure. Net, both tails roughly point away from the sun, as in our demonstration.

Sweet page from NASA with helpful animations and clear descriptions.

Follow the European Space Agency’s comet-chasing spacecraft, Rosetta, as it aims for the first robotic landing on a cometary nucleus.

Read this:  a “real” science article with a good set of detailed discussions of the types of comet tails and how they work.

Or, try this excellent piece by freelance science writer Craig Freidenrich on the inner workings of comets.

The Swinburne Centre for Astrophysics and Supercomputing’s educational site helps with details on the structure of comets.

Explore a public-domain catalog of Solar System images, from Hubble and other spacefarers.

Discover how Oort clouds may be one way star systems interact directly with one another, because the Oort clouds project so far out.

See the invisible part of a comet.

Find out all about radiation pressure.

Plan to catch sight of the meteor shower sponsored by Comet Halley.

Explore the origins of comets at this UC Berkeley site.

Check out NASA’s solar system photo gallery, with images from NASA and European Space Agency exploration missions and telescopes.

Visit the Lunar and Planetary Institute’s educational site, with even more hands-on activities for young astrophysicists. Roam their site for educator workshops and more.

OK, seriously, I’m not the only science blogger keen on comets.

A new comet is incoming this month (May 2014).

Our guy Euler was the first one to suggest that light exerts pressure, but we had to wait over 100 years to get to Maxwell, who proved it, and then another quarter-century went by before some Russians managed to measure radiation pressure. (Also, gotta love Google Books.)

Oh, and by 1915 the proof of radiation pressure made it into Scientific American.




Chasing Comets

Chasing Comets: Notes for Project Leaders #2Chasing Comets: Notes for Project Leaders #2

OK, we’re back for part 2.  Remember that our goal is to impart an intuitive, long-term understanding of how comet tails work.  I’ll give you an observation worksheet that students can use during the Comet Running game, but if time or attention-spans are too short for a worksheet, dispense with that element in favor of learning through movement and Socratic dialogue. (What? You think an engineer wouldn’t have read the Greek philosophers?)

If you have time and enough outdoor space for the “Game” version of this simulation, move right along to “Stage 2” now. The promise of a chance to make their own models is what will entice the students back to the classroom. Otherwise, save the great outdoor model for another time or place and move directly to “Stage 3,” building the individual models.

Stage 2: The Game

Chasing Comets

That’s One Big Comet

This is an outdoor game, and it works to best advantage with a nice BIG comet model. Four five-yard lengths of white fabric streamers attached to a single badminton shuttlecock (“birdie”) make our Comet Chase model. A playground ball or a soccer ball (around 8” in diameter) stands for the sun.   Sort the participants into groups of no more than five and no fewer than three, and move to the great outdoors. A grassy area is safest, because this game involves some complicated running; if you’re stuck with pavement, tone down the running to “jogging” and allow a little extra time.

Start by laying out the ground rules for the game. First, each group will get to play every role. There are three parts: being the sun, being the comet, and being observers back on Earth. Remind everyone of your local rules for behavior outside. It’s harder to listen to instructions out in the sunshine and fresh air!

Take a moment to review the lesson so far. Place the model Sun on the ground, at least ten yards away. Ask an adult helper or one of the students to stand about halfway between the class and the Sun and to hold the head of the comet

Chasing Comets

Large Comet Head With Coma

while you extend the tail’s long white streamers.   This model is much more evocative of the scale of a real comet, which has a tail tremendously longer than the diameter of its coma, or head—but it’s still not a scale model. Allow for some oohs and aahs, but move on to your query: which direction should the comet’s tail point? Don’t move yet; both you and your helper just stand in place.

Chasing Comets

Large Comet: Incoming or Outbound?

Don’t be concerned if it takes more than one answer to get the right one! Some may still want to know which way your comet is moving. But in a few moments, you should achieve the consensus that the tail should point towards the class and away from the sun.

Now, add the movement and ask everyone to call out which way for you to move. Ask your helper to start walking (slowly, please!) towards the sun and then to loop around the sun. You will need to move quickly to keep the comet’s tail pointing away from the sun. In fact, even if your helper cooperates by walking slowly, you will need to break into a run! As you run, if the students aren’t already hollering directions to you, tel them to keep reminding you which way to point the tail: away from the Sun!

Pause partway and while you catch your breath you can demo a technique for helping to align the tail while in motion. With your outside hand, hold the streamers. With your inside hand, point at the Sun. The tail-runners should always find that pointing at the Sun also means pointing at the comet’s head.

Now, it is finally the students’ turn. Run as many iterations as necessary to ensure that each group does each job at least once. For instance, for a class of 20, allow time to run the game at least four times.

The Comet Group: The comet group needs one Head and up to four Tail-Runners. Name the comet after the person who’s serving as the Head. Comets are always named according to the last name of the comet’s discoverer. So if you have Robin Williams as the comet’s head, then this will be Comet Williams. Getting the comet named after him/her may compensate for the fact that the “head” only gets to walk slowly around the sun.

Meanwhile, the tail-runners get to hold the ends of the tail streamers and run to keep the comet’s head between themselves and the Sun.  In the normal course, the “tail” group will tend to lag a little and spread out, but that actually serves to more-accurately represent the shape of the dust tail. If you’re working with a two-tails group, designate one especially determined runner to represent the ion tail by taking one ribbon and maintaining a straight line from the ribbon end through the comet head to the sun.

The Sun Group: The sun group stands in the middle of your running space. One or two group members hold the model sun overhead. This makes it easier for the Comet group to see if they have successfully aligned the comet head and the sun. If the tail-runners stray out of line, members of the sun group need to to shout out “Got you! Got you!” or “Solar Wind Coming!” to warn them that the solar forces are blasting the tail.

The Astronomer Group: The people who are not part of the sun-comet demonstration still have a critical role. They are not just watching other people play the game, but they are tracking the shape of the comet’s tail as it passes around the sun, as observers on Earth. Depending on their perspective at each point in the comet’s orbit, the tail will appear longer or shorter. For example, if the comet is roughly between Earth and the Sun, the tail may look short, because it is stretched towards us. If you have time for writing, ask the Observers to sketch the comet as they see it. (See the handout.) In an average class, each student will get to observe the comet at least twice, which is very helpful for catching the unexpected views.

When every group has had a chance to play every role, take a few minutes to review one more time. As a comet is orbiting around the sun, which way does its tail point? By now, everyone should be willing to state that the tail always points away from the sun.

Still, you may still have a few hold-outs who are not quite sure this can be true. If you are lucky and it’s a sunny day, you have a hole card to play. Invite the students to each imagine that they are comets. “Guess what? You can see exactly where your tail would be. Who can point at it? Where’s your tail, Comet Human?”

If you are not saved by the insight of a student who’s totally absorbed the lesson, it is OK to resort to hints. “Everyone has one. It’s easy to see. Yes, you can see your comet tail! Where is it? Which way does a comet’s tail point? Right: away from the sun. Where’s the sun right now? What do you have that’s pointing away from the sun? It’s not bright and shiny like a comet’s tail. It’s dark, because there are no sunbeams there.

“Yes! Your shadow is your comet tail. It points away from the sun, always, no matter what direction you run.”

Stage 3: The Reward

Finally, everyone needs a model comet of their own to take home and show off and share with family members everything about how comet tails work. This is not an art project; it’s an opportunity to review and experiment individually. If some students are fussy about carefully arranging their streamers to make a colorful pattern, that is all right, but the point is to assemble a working model.

Each participant needs 24 feet of curling ribbon and a birdie (remember what I told you earlier about calling it by its proper name—be prepared for lots of giggling and teasing if you insist on that) . Cut the ribbon into eight lengths of roughly 3 feet. It is perfectly all right—and in fact more realistic—if the streamers come out various lengths. And depending on the students’ social skills, it is also all right for them to exchange colors once the cutting is done. (There are always some who prefer to discover a multi-color comet and others who prefer monotone.)

Once each student has six streamers, have them tie one end of each streamer to the head of the birdie.

Chasing Comets

Detail–Attaching Ribbon For Comet Tail

Your meticulous planners will distribute them evenly around the netting; others will be clumped randomly. Either is fine. Every comet is unique and most are quite non-uniform.

Be real. This project is not done when it the comets have been only built. Everyone needs a chance to try them out. They will, of course, want to toss them around the classroom; if this is not acceptable, make some provision for them to try out that technique outdoors. More scientific, of course, as time permits, is to allow the participants to take turns trying out their comets in the pretend “solar wind” of the classroom fan. As long as they willing and able to mind safety rules about working around a fan, by all means have everyone try out the tail position approaching, passing, and retreating from the Fan Sun. But don’t get all hot under the collar if other comets are flying through the room while you monitor the fan users. Just imagine you’re in the Oort Cloud and you’ll be OK.

Up next:  Supplies You Need and Resources You Can Use

Chasing Comets

A Cluster of Comets, Incoming & Outbound

Chasing Comets

Chasing Comets: Notes for Project Leaders #1Chasing Comets: Notes for Project Leaders #1

In this activity, the most important idea is to explore and experiment with models and games to understand how a comet’s tail behaves as the comet hurtles around the sun. The key concept is that the comet’s tail is being pushed away from the sun by the ionizing radiation, solar wind and even the light itself blasting out of the sun. This means that when the comet is inbound, approaching the sun, its tail streams behind it, like a horse’s tail. But on the outbound journey, as the comet leaves the sun behind, its tail flies out in front of it. What we hope the participants will take away from these activities is a picture of what a comet looks like as it moves and the knowledge of why it looks that way.

Comet-tail behavior simply makes sense when “experienced” from the comet’s point of view.  If by any chance some of these facts are a discovery for you, too, don’t feel like you have to keep it a secret that you are learning–have fun with it. A key ingredient in the formula for growing a scientist is that finding out how the universe works is fun. Or, in the words of one physicist profiled in the film Particle Fever: The real answer to “why do we do this is . . . because it’s cool.”)

Keep in mind the constraints of your particular situation when assembling your materials and pre-planning the project. For instance, if there aren’t enough classroom scissors or if session time is tightly constrained, you can pre-cut the ribbon for the individual comet models into 3-foot lengths. Be aware of opportunities for participants with special needs—for instance, the comet-running activity does require at least one person to be standing still. In return, that one who just can’t stand still could be a pinch-runner. If the group as a whole isn’t particularly fast-moving, the “running” game can be done at whatever pace suits the team.   (One can be a “student” at any age—most of us middle-aged folks are not exactly speed-demons.)  If you’re planning this as a home-schooling project, this is one you’ll want to save for a get-together with other home-schoolers–you need at least three players and it is ever so much more fun with a group.

Stage 1: The Small-Scale Experiment

This description may look long, but that’s just to let you walk through it easily and to share some photos to help. This whole Stage 1 should take about fifteen minutes, tops.   I’ll spare your weary eyes and park the “Stage 2” and “Stage 3” activities in the next posting–but don’t worry, the entire activity fits into a single science session if you can claim an hour’s time to play with.

Before distributing materials, bring out one individual model comet, the sample to be used for the models everyone will take home. It’s simply an ordinary badminton birdie with long streamers of ribbon tied to it. For now, keep the ribbons bunched up inside the net of the birdie. Explain that the ball at the end of the birdie is the comet’s nucleus, the frilly part can be its atmosphere, or coma, which begins to form as the gas and dust which jets away from the outer layers comet as it warms up.

Chasing Comets

One Small Comet

Notes: I’d suggest that you relax and let your sample comet be imperfect—comets are messy creatures by nature and you don’t need that one super-meticulous individual slowing down the whole event by striving to exactly matching a perfect sample. If you have an older, more experienced group of comet enthusiasts to work with, you can interject the extra information about the distinction between the ion and dust tails—perhaps even represent them by different ribbon colors. On the other hand, if you’re working with anyone between the ages of 5 and 15, and you don’t want to deal with distracting snickers and giggles erupting through the group, simply refrain from using the technical term for a birdie. Oh, come on, you know why.

OK, back to it. The ribbon represents those gases and dust particles that make up the comet’s tail(s). Now, if we toss our model across the room, what happens to the streamers tied to it? Right . . . they float out behind. They don’t stretch out in front or clump in a bunch around the head of the “birdie”. You can demonstrate by trying to throw your comet backwards: hold the tail in front and toss, but the tail will just fall back to the head and—if your throw is a mighty one—end up in back again..

Now, invite answers to a key question: why does the ribbon float behind? What pushes the tail behind the cone as it flies through the room? With a little nudging, you should get general agreement that it is the air pushing on the lightweight streamers, shoving them behind the “head” of our comet.

But now we must turn to a more difficult line of questioning. Pull out playground or soccer ball (a handy model for the sun), and ask one student to stand and hold up your Sun so everyone can see the next portion. Bunch up the comet’s tail in the back of the shuttlecock again, and carry the comet in a “flight” around the “Sun”. As you move, ask the students to think hard about what happens to the comet’s tail as it whips around the sun.

Start easy. Shake out the streamers, and stretch them out with your free hand. Move the comet towards the sun. Which way should I point the streamers? Everyone will be quick to tell you to pull them backwards, away from the sun. Now, place the comet at its closest approach to the sun, just before it curves back to head into deep space again. “I’m at the Sun now,” you can say, “zooming around the back of it. And moving as fast as I’ll go in this journey. Which way should the streamers point?”

Usually this question generates some disagreement. A reasonable argument would be that you should hold the streamers behind the comet, as it moves, which would mean the comet’s tail would point along a tangent to its orbit around the Sun. (Even if the students are covering tangents in math, please don’t interrupt yourself to pause and discuss tangents right now! Use this lesson later to enliven the math session.)

Chasing Comets

Tail Behind?

Chasing Comets

Tail In Front?

Chasing Comets

Tail Sideways?

Some students may suggest—quite logically–that when you are that close, the Sun’s gravity should pull the tail towards it. If the group is large enough, you should also get someone who can argue that the tail should point away from the sun—for now, it doesn’t matter if this is a knowledge-based claim or just a contrarian viewpoint from snarkiest person in the room. Whatever hypotheses are offered, just accept them as proposed solutions and demonstrate what each would look like.

Finally, move to the “outbound” portion of your comet’s orbit. “Our comet now flies on away from the sun, perhaps to return in another century or two. Now, which way should the comet’s tail point?” Again, if you have managed to keep a poker face so far, the most popular answer is likely have the tail streaming behind the comet. As before, accept and demonstrate each of the guesses. If students have reasons for their theories, let everyone hear them. Discussing and justifying hypotheses is an integral part of the real scientific process.

If you have access to a blackboard (oh, well, it’s modern times, so, okayokayokay, you can use your smelly whiteboard or that fancy tablet-linked projector), now is the moment to leave off demonstrating with the model and sketch the competing hypotheses for everyone to see. Your picture will look kind of like this. Please remember to Keep It Messy.

Chasing Comets

Discussing Possible Tail Directions

Have you ever read one of those annoying mystery stories in which the author leaves you in the dark about a critical fact that solves the entire case? Well, here too, we have denied our puzzle-solvers an important clue. So, tell the group it’s time for a change of topic. But actually what we’re doing is rolling out the narrative twist that makes the whole thing so cool.

Here on Earth, it is air that pushes the streamers on our comet model. But how much air is there out in space? (So little that you might as well say “zero”!) But without air, why should any comet have a tail at all?

What comes out of the sun? You should hear the following answers: heat, light, maybe even radiation. But has anyone heard of the solar wind? The sun blasts out particles, too? The sun is shooting out plasma, protons and electrons flying through the solar system at thousands of miles per hour. This is the solar wind, which blows through the solar system all the time, at thousands of miles per hour. The particles are tiny, not even as big as atoms, so it is an invisible wind. And like wind, it’s not perfectly even, it gusts and changes from moment to moment as the Sun itself changes.

All of those things we named help to make our comets look the way they do. Consider your audience…

Explanation #1: You are all correct. All of that stuff blasting out of the sun–light, radiation, heat, and the solar wind–shove all that stuff leaking out of the comet into a tail. And since all that stuff is coming from the sun, the only way the tail can point is away from the sun.

Explanation #2: All of those answers are correct . . . and they all combine to make a comet’s tail. The heat of the sun warms the comet to free the gases and dust. The solar wind blasts the gases—and the particles in the solar wind also interact with those gases, stripping some of their electrons to make that part of the tail a glowing stream of ionized gas. The radiation from the sun actually can push things, and that pressure is just strong enough to shove those tiny dust particles enough to counteract their tendency to fall towards the sun. And the visible sunlight reflects from the spread-out cloud of dust, making the comet shine in our night sky.

Again, with older/experienced participants, now is the time to clue them in that radiation pressure—the totally cool idea that sunlight itself exerts pressure—exists because light is electromagnetic radiation and electromagnetic radiation is a wave and a wave [] pushes on the objects it encounters. You may not feel battered and bruised by the TV and radio waves powering through you day and night or be physically bowled over by the sunlight forming a gorgeous rainbow. But: it’s enough to push fine grains of dust. The only sad thing about radiation pressure is it’s not common knowledge yet—it’s been proven since 1873.

To represent these solar forces, we need to make a breeze. For that job, a fan does the trick. When we turn it on, it blasts a healthy “solar” wind. (Be sure to experiment in advance with your fan and sample comet–there’s a lot of variation in fan settings.)

Chasing Comets

Inbound Comet

Hold the comet in the “inbound” position, with the front of the birdie pointed at the Fan Sun.  Yes! We were all correct: the tail points behind the comet as it moves towards the sun.

If the fan is strong enough, you can also use the model to hint at how the length of the comet’s tail changes. Far from the sun, the comet has no tail; far from the fan, our streamers dangle to the floor. A little closer in, a real comet’s tail appears as a pale streak behind it; as you approach your fan, the model’s streamers lift up and begin to flutter weakly behind it. Near the sun, the tail stretches out millions of miles behind a real comet’s head; near the fan, the your streamers stretch their full length.

Now, what about when the comet is heading away from the sun? Which way will the tail be pointing, now that we know about the solar “wind”? Nearly everyone will see, now, that it must point away from the sun.

Chasing Comets

Outbound Comet

Demonstrate that this works: you point the birdie’s nose away from the fan, turn on the blast, and the streamers flow out over the front of the birdie. The shape of the birdie helps emphasize the incongruity of our expectation—that the tail goes behind—with the reality: the solar forces push the tail.

If the class has patience for one more test, add the third question: what happens when the comet is rounding the far side of the sun, and is pointed “sideways”? Hold the comet model perpendicular to the flow of the fan.

Chasing Comets

Comet At Perihelion

Let everyone see how the tail sweeps out to the side of the comet. It always points away from the sun, no matter what direction the comet is pointing.

Here’s 13 seconds of one model comet in action:



Coming Real Soon:  Stage 2





Chasing CometsChasing Comets

As a  re-entry activity, let’s fall right into the project which inspired the overarching theme for this so-called blog:  cometary tails.   That is, in this instance, we’ll be “studying” the behavior of the tails of actual comets falling along their orbits about a star.    But of course, this is a “Messy Monday” project, so it  involves running, arguing, and playing with scissors (not all at the same time).

So far, the only star whose comets we’ve observed have been those of our own Sun, but as our star is not particularly unusual, it’s likely that comets ply their trade throughout the cosmos.  We’ll not be delving too deeply into astrophysics, instead we’ll be building fun models of comets and playing games which illustrate the apparent motion of a typical comet’s tail.  If you’re running this project as part of a school science program, you can double-count the activity as a P.E. session, as the central game involves more than a bit of running, though not likely moving as fast as a comet.

Just as a reminder, what I want to give you in these “Messy Monday” project descriptions is 1) enough background on the science that you’ll be prepared for questions and have resources to draw on if your own curiosity is triggered, 2) a play-by-play description of running the project with a group, recognizing that your time and resources are limited and your participants will vary in both interest and prior knowledge, and 3) a shopping list detailed enough to help you minimize your costs as well the time you have to spend assembling supplies.

Shoemaker-Levy panoramic (courtesy NASA-NSSDC)

Fragments of Comet Shoemaker-Levy heading for Jupiter (courtesy NASA-NSSDC)

So, What Do You Want to Know?

For thousands of years, humans have wondered at the strange visitations of comets.

Natural philosophers of the middle ages studying comets.

Natural philosophers of the middle ages studying comets.

In our time, people now understand that comets are not harbingers of doom or annunciations of the births of kings but fellow travelers in our solar system, icy bodies wheeling in towards the sun and shedding a fraction of their substance as they approach the sun.  However, a key aspect of the comet’s tail remains counterintuitive to us earthbound air-dwelling creatures.  The tail of a running horse flows behind her as she gallops, so we naturally expect that the tail of comet simply flies behind it as it plunges along its course.  But a comet’s behavior plays tricks with such expectations.

Where do comets come from?  The Solar System is a big place, but for most of us, the territory ends with Pluto, the Object Formerly Known as The Ninth Planet.

Great_Comet_of_1577 by Georgium Jacobum von Datschitz public domain

The Great Comet of 1577

However, if you’re a fan of Cosmos (either Carl Sagan’s or Neil DeGrasse Tyson’s version) or if your school is lucky enough to have new textbooks, then you’ll know about the Oort Cloud , that sphere of orbiting material from which most comets emerge.  Do you realize how much farther out this region is? On a scale of one inch per 100,000 miles, in which the orbit of Pluto would be one mile across, the distance from the Sun to the Oort Cloud would be the length of the state of California.  It’s even been hypothesized that the Oort clouds of neighboring stars may physically interact, exchanging comets.

The Oort cloud is a long way out, but it’s still a part of the Solar System, because the objects there are still subject to the Sun’s gravity.  Occasionally, a piece of this clutter is jostled from its orbit and begins the long fall towards the sun.  Depending on the path it takes as it zooms around the sun, the comet may slingshot out of the solar system entirely or it may settle into a new orbit, returning to loop around the sun on a regular schedule.   For instance, Comet Halley returns every 86 years.  The last time round, it actually came in ’86–1986 that is.  I was lucky enough to visit New Zealand that year, so I can confirm that Comet Halley was extremely unspectacular that year–only just barely visible.  Fortunately, New Zealand itself is spectacular every single day of any given year.    NASA was more successful, having a noticeable advantage in telescope access.

Babylonian Astronomers Wrote Down Their Observations of Halley in BCE 164

Babylonian Astronomers Wrote Down Their Observations of Halley in BCE 164

Comet Halley's Appearance Dooms King Harold in 1066

Comet Halley’s Appearance Dooms King Harold in 1066

Comet Halley in 1910

Comet Halley in 1910

Comet Halley in 1986 (Courtesy of NASA)

Comet Halley in 1986 (Courtesy of NASA)

                                                                                                                                                                                        But why do comets even have tails?  We don’t see shiny tails glowing in the wakes of our planets.  Well, it all has to do with the change in environmental conditions as the comet moves towards the Sun.  Comets are composed of water ice, frozen gases, rocky matter, and even traces of organic compounds.  As this frozen jumble approaches the sun, it warms up enough that the various ices in the outer layers of the comet become gaseous—water vapor, ammonia, carbon dioxide.  These gases bubble and boil into a misty cloud, so the comet will have an atmosphere of sorts, called the coma, for the duration of its passage through the inner Solar System.  The gas expulsions may even shoot out of the comet’s rocky layers like jets, causing the comet itself to tumble as it falls along its inward path.  At the same time, very small-scale “dust” particles are swept from the cometary nucleus.  This is not the heavily-organic dust we find under our furniture here on Earth (if you really want to know what’s in household dust don’t use “Google images”;  stick to text searches or just ask your friendly neighborhood allergist).  What we mean is that the particle size—a few microns—is extremely fine, about the same size as the particles in cigarette smoke.

We get our fabulous cometary tail once these newly-ejected gases and dust of the coma approach the sun just a bit closer, enough that the various solar emissions can have their ways with the comet’s atmosphere.   First, there is sunlight itself, which acts in several ways to provide us with the visual spectacle of the comet’s tail.

The simplest role of sunlight is to shine on the cloud of dust ejected from the nucleus.  That’s the main tail we see.  But that still doesn’t explain why the dust forms a tail at all:  the secret is that light, as electromagnetic radiation, actually exerts pressure on objects, and with tiny objects like cometary dust this radiation pressure force is enough to fan that  material out from the core.  Plus, there is a cool bonus “secret”: that most comets actually have two tails—one formed by the gases and one formed by the dust.  The ultraviolet radiation in sunlight blasts the gas particles, stripping away electrons, and so creating a mass of ionized gas, which fluoresces (mostly blue) in sunlight. Then those glowing blue ions are blasted in a straight line away from the sun by the solar wind, a stream of high-energy particles hurtling at supersonic speeds through the solar system.  The solar wind is a wonderfully intricate system in its own right, but for our purposes here it is most important to convey that, like earthly winds, it consists of particles moving at high speeds and that its direction is away from the Sun.

The result of all these combined forces is that a complex, continuously shifting cloud of gases and dust streams out from a comet during its time in the inner solar system and that tail—or, rather, pair of tails—points away from the sun, even when the comet is on its way back out to its origin.  (If you’re a die-hard comet enthusiast, you’ll know that the dust tail does curve inward a bit, as the small particles of dust battle with the solar forces, striving to curl into their own individual orbits about the sun, but from our earthly perspective, the outward forces have the upper hand.)

In the next installment, we’ll get down to the nitty-gritty of building our own comet models and playing a game of As the Comet Tail Flies.

Oh, yeah, and I’m not making things up about radiation pressure.  Consider the prospects for spaceflight under the power of light!

The Japanese IKAROS spaceprobe in flight (artist's depiction by Andrzej Mirecki).

The Japanese IKAROS spaceprobe in flight (artist’s depiction by Andrzej Mirecki).

Avoiding HyperboleAvoiding Hyperbole

OK, right, it’s been so long since the last post that even my backup program is writing me off as too far gone. Too bad, Updraft, back to work, you lazy batch of code.

True, some comets hare off to interstellar space on hyperbolic orbits. However, two or three things:
1) There’s much to be said for the sweet homey stability of an elliptical orbit.
2) On a hyperbola, there are two arms, and who’s to say if you’re on the right one?
3) My top speed is less than 2 m/sec whereas an escape trajectory on Earth demands moving at about 11,500 m/sec.
4) I’m not actually a comet, I’m a human being who is interested in comets both as astronomical objects and as metaphorical images.
5) That’s four or five things.

Aiee Hyperbola Wiki

Redlining on a hyperbola. Aieeee!

Stuff happens, and it’s not exactly a huge crime to neglect a blog that no-one is reading. Last year, I whined about the inconveniences of having a broken arm. Well, there’s worse stuff than a broken arm. Besides, I needed time to read other people’s websites. Like catching up on the doings at Gunnerkrig Court. Like reading anything about robots that turns up on IEEE Spectrum. Or reliving grad school days on Jorge Chan’s Ph.D. comic. Or vacillating between reading Allie Brosh’s hardcopy book or her online stories at Hyperbole-and-a-Half.

In the meantime, I’ve managed to keep up a little better on the easier-to-maintain Facebook & twitter side of things, under the Pixel Gravity moniker.

But it’s time to dump more stuff out on the world and see if anyone who isn’t a spammer notices.

Here’s the deal:  I’ve got a year’s worth of science projects for kids that I want to share.  Maybe they’ll be a book too, some day.  (Insert self-knowing laugh here.)  I’m a year behind on delivering my Grand Canyon stories & pictures, which I promised my fellow-travellers would be “up” by the end of last summer.   But there’s other stuff I want to address as well.  So there will be a little discipline applied, in a way that would help any of my imaginary readers look ahead for the next entry in a category of interest.

First week of the month:  One “Messy Monday” project

Second week:  One “Grand Canyon” entry–either a half-day of storytelling or a photo album.

Third week:  Science & fiction stuff–the science fairly topical, the fiction

Fourth week:  An extra week to play catch up, first on the Grand Canyon, and later on Messy Monday, but also a piece of flexible time for interesting stuff of the moment.  For instance, Memorial Day Weekend will yield four days of BayCon 2014.

Next up:  Comets in orbit…