Cometary Tales Hands-On Science Cooking With Kuiper: Notes for Project Leaders

Cooking With Kuiper: Notes for Project Leaders

(update:  2/18/2015)

Last week on the tvweb, this happened: astronomer Derrick Pitts turned up once more on “The Late Late Show”.  And even though science-loving Craig Ferguson has moved on to new horizons, Director Pitts stayed and showed Guest Host Wayne Brady how to make a comet.  So I looked back at my entries for this project and realized they need some updates, and particularly some visuals. Have patience–it’s a multi-entry blog feature, so look for two more entries for the complete Updated Edition of “Cooking With Kuiper.”

The Kuiper Belt–that donut-shaped aggregation of hundreds-of-thousands of rocky objects orbiting beyond Neptune–is one of the most interesting regions of the Solar System just now.  Just last year, NASA’s Deep Impact explorer hurled a probe into the surface of Comet Tempel 1, flinging up a curtain of debris to reveal more about the comet’s composition.

Deep Impact's probe sent back this image just before striking Comet Tempel 1 (Image: NASA/JPL-Caltech/UMD)

Deep Impact’s probe sent back this image just before striking Comet Tempel 1 (Image: NASA/JPL-Caltech/UMD)

NASA’s New Horizons mission is due to arrive in July 2015 at Pluto–the most famous Kuiper Belt object–to observe the newly-redesignated dwarf planet and its five moons and then head out to explore.  You can check in on the progress of the mission at NASA’s home for New Horizons.  There is a general agreement among astronomers that the comets which return again and again (periodic comets)  began in the Kuiper belt.

In this project, we’ll be building a model of a comet using household supplies to represent most of the comet’s components and dry ice to capture the icy-cold environment of the Kuiper Belt.   While most Messy-Monday projects are entirely hands-on this particular activity is meant as a demonstration with controlled audience participation.  Some students may be careful enough to work with dry ice…but too many are not, and the step at which the dry ice is added can be dynamic and unpredictable.

A study of comets draws in much of what students should know about their planetary system and extends that knowledge into new and intriguing areas.  Students in intermediate grades probably know the basics of comets…that they come from the far reaches of the solar system, that they have tails, and that a comet crashing into the earth makes a cool disaster movie.  They might be surprised to know that scientists still want to find out more about comets, because all we know about comets so far is from watching them on their travels through the solar system.  Just a few months ago, the Rosetta spacecraft launched in 2004 by the European Space Agency actually landed a robotic explorer named Philae on Comet Churyumov-Gerasimenko, so why not launch an investigation into the nature and structure of comets by building our own lumpy, irregular, gas-spewing comets?

This activity is best paired with at least one hands-on activity centering on comets.   The second activity in this series combines a crafting-style model construction project and a cometary motion simulation game.  Other resources can provide other activities.  For instance, students can make a flip-book illustrating a short-period comet’s behavior as it travels from the orbit of Neptune to the sun and back.  And users of Pixel Gravity can run a simulation of the comet impact which led to the demise of the dinosaurs.

In the next installment, we’ll assemble a supply list for this project.  I recommend you  plan to build at least two comets, to let more kids participate and also to illustrate just how different two comets can be.

 

You might also like to read:

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

Messy Monday: Science Projects for Kids, Teachers, and Parent HelpersMessy Monday: Science Projects for Kids, Teachers, and Parent Helpers

Welcome to the first official posting under this new category.  In these installments, I’ll be sharing science projects developed over many years while serving as The Science Mom at my local elementary school and in a community after-school program.   When my friend Jean Southland and I first started the in-class projects, the teacher invited us in on Mondays, to create a fun activity for that worst-of-days to students, the First Day of the School Week.  We fooled around with ideas to give this extra science class a name and settled on Jean’s simple and inviting “Messy Monday”.  Since then, Jean moved on to wider-scale education duties, from teaching to administration, and she is now head of  a local charter school.  In the meantime, I continued with developing classroom-scale science projects and coaching a small robotics team.

When the youngest of my kids finally moved on from elementary school and my geek needs were being satisfied by playing with robots, I felt twinges of guilt that I was leaving the next round of students in the lurch.  The most-frequent comments I heard when running science project sessions could be summarized as: “I could never do that”.  Sometimes it was the teacher, in which case she/he would mean  “I can’t spare the time to figure out supply lists, shop for stuff, sort out materials, and test procedures.”  Other times, it was another parent, in which case the meaning was either  “I could do that, if only someone would explain what it’s supposed to mean” or “I understand the science, but someone needs to give me a checklist to follow.”   And in these times, potential cost is always a concern, as most supplemental projects—from field trips to science experiments—end up being funded by parents or from teachers’ own pockets.

In these episodes, I’ll be having a stab at meeting both sets of needs.  With any luck, the end result will be a book of “recipes” for science projects with enough information provided for teachers to slot into their curricula in order to satisfy the science standards they must meet, with clear supply lists to distribute to classroom-helper parents, and with step-by-step instructions for completing projects that any interested parent or teacher will be able to not only follow but build upon to suit their own audiences.  While (like every other blog in the Known Universe) the ultimate result is to be a book of projects that a teacher or parent helper could have at hand, in the short term, there will be first, these erratic blog entries and second, a series of leaflet-style e-docs in a more readable/printable form, to be available from the usual e-book suppliers.  Think of the blog entries as the beta version, the leaflets as the Basic Edition release, and the eventual book as the Portmanteau Edition, with updates, extensions, and add-on packs as needed.

To open the subject, I’ll be delivering a flurry of quick posts to get things started, but then will back off to a more regular pace.  The goal is to deliver one project-worth of information in no more than two weeks.

Every Messy Monday project guide has four key components:

  •  A set of notes for project leaders, sketching the key elements of the project and the science topic it is meant to address
  • A detailed supply list, structured to make it simple to purchase supplies for either a one-shot demonstration or for a classroom-sized group activity.
  • A set of instructions for working through the project with students, including commentary to help cope with common classroom-management issues, questions that are likely to arise, and issues to keep in mind from safety to fairness.
  • A rough estimate of the cost to run the project.

So, let’s get started with a truly cometary project…

On Aisle 42, Universe Components: The Atomic Marshmallow ProjectOn Aisle 42, Universe Components: The Atomic Marshmallow Project

Now that you have all of your supplies ready, it’s time to guide your group through the construction of a model atom.

Start by handing out the marshmallows and ice-cream topping pieces.  With younger participants, it can maintain focus if you mention that there are extra supplies for snacking on afterwards.

Start with the marshmallow.  Most of an atom is empty space.  And most of a marshmallow is nothing but air frothed into sugar.  So this marshmallow represents the “empty” space of an atom.  For older participants, you can encourage them to think of the sugar of the marshmallow as representing not only the energy that permeates what we call “empty” space but also the forces that hold the atom together.

For a very long time, the atom was believed to be more-or-less of uniform density, an amorphous mixture of tiny negative particles called electrons swirling around in a positively-charged “pudding.”  In 1911, Ernst Rutherford and his team completed a series of experiments that shocked the physics community by revealing that most of the mass of an atom is concentrated in a tiny, central nucleus containing all of the positive charge.  For our model, in honor of Rutherford, we’ll build a helium (He) atom, which has a nucleus containing two protons and two neutrons.  (Much of Rutherford’s research focused on the alpha particle–which happens to be exactly the same as a helium nucleus.)

Let your dark-colored candies be protons and your light-colored candies be neutrons.  (It doesn’t really matter, but textbooks often draw protons as dark dots and neutrons as white dots.)

Using the wooden skewer or toothpick, drill a small hole in the side of the marshmallow. Now use the same toothpick or skewer to push those nucleons (a word which here means “candy pieces representing protons and neutrons”) into the center of the marshmallow.

This is a good time in the activity to stop lecturing and instead gather suggestions from the participants and sketch their ideas on a board if you have one, or to gather around some sketching paper for discussion purposes.  You can expect to see pictures that look much like a planetary system, because that’s the way the atom often (still!) is drawn in textbooks.  You might have a knowledgeable participant who’ll shout out something like, “Shells!  The electrons are in shells!” or “They’re in the Cloud!”  Regardless, during the discussion, build on these volunteered suggestions to reach a description of the electrons as whirling around the nucleus in a cloud, going so fast that you can’t really tell exactly where they are, only that you know roughly how far they are from the nucleus.

At this point, we have a positively charged ion, because we haven’t added any electrons yet.  A helium atom needs two electrons, negatively-charged particles, to balance out the two positively-charged protons.  Once it was established that the positive charge is concentrated in the nucleus, where did researchers decide that the electrons belong?

Our helium atom’s two electrons do indeed share an electron “shell”, a layer of electrons a known distance from the nucleus.  So let’s put a very thin, energetic, sparkly shell around our atom.

Before setting up the shell supplies, pause to demonstrate the procedure.  If you’re working with younger students, you may need to stress that everyone will get their turn.  If the “mess” part of the activity is an issue, set up a protected area where the messy activity is OK and let the participants queue up to build their atoms in assembly-line fashion.

To create the “electron shell” skewer the marshmallow firmly on the wooden stick, then very briefly dunk it into the water, then tap off any excess water into the water container. Tapping off excess water is important, because otherwise the marshmallow can get soggy, which makes for a less-attractive candy atom.

Marshmallow on skewer dunked into clear plastic cup half-full of water.
Dunk
Wet marshmallow held by skewer on edge of plastic cup of water, drops of water dripping off.
and un-dunk.

Each group needs a container with about a cup of water in it and another container with a packet of dry gelatin mix emptied into it.  (For fun, choose a gelatin color in keeping with whatever events are ongoing, or a local sports team’s colors…anything to drive interest.)

Finally, gently swirl the damp marshmallow in the gelatin mix.

Set the decorated marshmallows aside on a sheet of waxed paper or a plate.

As time permits, participants can make other atoms…stuffing different numbers of protons or neutrons into marshmallows and adding a shell of electrons.

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