Cooking With Kuiper: Notes for Project Leaders

December 27, 2012| cometary| 0 Comment | 5:23 am

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Hands-On Science

(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)

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: 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.

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.

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.

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:

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.

On Aisle 42, Universe Components: One Will Make You SmallerOn Aisle 42, Universe Components: One Will Make You Smaller

A Top-Down Search for the Strange Charm of Putting Up With Those Quarks at Bottom of the Universe

For part two of our universe-construction project, while the helium models dry, it’s time to delve into the depths of the sub-sub-atomic universe.

Consider those carefully-constructed model atoms. Each contains protons, neutrons, and electrons.

As it turns out, with electrons, there are (so far as physics can determine at present) no smaller particles needed to build an electron. Electrons are part of a group of six elementary particles called leptons. Some of these leptons–the neutrinos–were predicted to not even have any mass, but experiments have shown that while they are incredibly low-mass, neutrinos do have some mass. Interestingly, these experiments leading to even more new developments in fundamental physics and the Standard Model theory. Still, electrons are by far the most numerous leptons (at least in our corner of the multiverse.)

In our candy-based model, we have more than one proton crammed into in a nucleus. Each of those protons has a positive charge, but we all know that objects with the same charge repel each other. Why does the nucleus stay together?

In our model, of course, there is all that sticky candy. But in the real atom, there is also something that, in its own way, makes protons stick together. These other particles are one type of another class of matter, called mesons. These strange, essential, particles are stable only inside the nucleus, where (like our sticky marshmallows) they act as a “glue” to hold protons and neutrons close together.

Given that extremely tiny leptons have been observed, as well as tiny mesons inside the nucleus, protons and neutrons may begin to seem too big to be elementary particles. Sure enough, it turns out that protons and neutrons are also made of smaller particles. And those mesons, too, are made of those same even-smaller particles. And, while it took thirty years to search them all out, a total of six more fundamental particles (on top of the six leptons) have been found. Most of the matter we know about only requires two of those particles–plus the electron–but modern physics predicted six, and sure enough, there are six of them.

Meet the QUARKS. Their six kinds are: up, down, charm, strange, top, and bottom. Each kind comes in a matter form and an antimatter form.

Intriguingly, the terminology for “kinds” of quarks is flavors. Other characteristics of quarks and leptons include color, another clue to the pleasure scientists find in these discoveries. For now, we’ll experiment with the flavors of quarks. Unlike real quarks, we will use macroscopic objects that also happen to taste sweet.

As usual, if you’re working with youngsters, begin by reassuring everyone that there will be plenty of time to eat their quarks later. Each person gets one each of the six flavors of candy…quarks. Because the candies will be handled a lot during the first stage, tell them not to open the wrappers yet. Observe the candies. One side has the brand name on it, and the other side is plain. If we put the candy name-side up, we’ll call it a quark, and if it has the plain side up, we’ll call it an antiquark.

Quark vs Antiquark

A meson is formed by pairs of one quark and one antiquark. Give the group some time to see just how many combinations can be made of such pairs. (A few special mesons combine two or three such pairs, in quark combinations.)

A Small Set of Mesons

This will take some cooperation–participants will want to get together and different groups will organize their tests differently. Meanwhile, if you have access to a whiteboard or poster paper, you can sketch out a list of simple mesons shown below. For smaller (or older) groups, you can also pass out copies of this grid and let everyone check off the combinations as they are discovered.

	quark	antiquark	candy (name)	candy (plain)
bottom eta	b	b	pineapple	pineapple
Upsilon	b	b	pineapple	pineapple
charmed eta	c	c	purple	purple
D+	c	d	purple	peppermint
D0	c	u	purple	red
J/Psi	c	c	purple	purple
Strange D	c	s	purple	green
Charmed B	b	c	purple	pineapple
Kaon0	d	s	peppermint	green
B0	d	b	peppermint	pineapple
Phi	s	s	green	green
Strange B	s	b	green	pineapple
pion	u	d	red	peppermint
kaon+	u	s	red	green
B+	u	b	red	pineapple
Charged rho	u	d	red	peppermint
Kaon*+	u	s	red	green

What’s important from this exercise is realizing that all of these two-quark combinations can really happen. Some of the mesons are the ones that help stick nuclei together. Others are found in outer space, as cosmic rays. Others are only found when scientists smash other particles together to find out what they are made of. Recently, the last of the mesons described by this model was detected by an international team of physicists, using the Large Hadron Collider at CERN, in Switzerland. This prompted huge celebrations by physicists and the process inspired a documentary film about the search for the Higgs Boson, Particle Fever.

When I ran this project at BayCon in 2017, one of the young participants scanned the list above and said, “What about the top quark?” Trust a science-fiction fan to spot an anomaly. Indeed, none of the known mesons make use of the top quark, which is the most elusive one of all, and in some ways the most peculiar. The top quark is extremely unstable–even more ephemeral than the strange, charm, and bottom quarks–and it requires a large particle accelerator to observe one. (Fermilab managed it first; now CERN‘s Large Hadron Collider holds the record.) Even then, once produced, a top quark vanishes in 1/1,000,000,000,000,000,000,000,000th of a second. The top quark is also amazingly massive, fueling the deep interest in the nature of mass itself, which many think is one of the functions of the Higgs boson, which itself has only recently been (tentatively) observed. Scientists at CERN hope to use the relatively massive top quark as a test laboratory to verify their (provisional) Higgs boson observations.

Three-quark particles are called baryons–the most common of these are protons and neutrons. The next step for our own quark exploration is to find the combination of up and down quarks that yields the proton and the one that forms a neutron. Each person has 2 peppermint and 2 of one other color to play with. Each group can also pool resources (still keeping those candy wrappers on) to mix and match groups of three using only 2 colors of candy.

To sort out which of these combinations works requires one extra piece of information. We know that an electron has a charge of -1, a proton has a charge of +1, and a neutron is neutral, with a charge of zero. Another cool feature of quarks…and one of the hardest things their discoverers had to come to terms with…is that they have fractional charges. Before quarks, everyone used to think of a charge…equal to the electric charge of an electron…as an indivisible thing. Just like an atom. But just as it has turned out that atoms aren’t indivisible, neither is charge.

Up quark’s charge: +2/3

Down quark’s charge: -1/3

So, with just a little arithmetic, we can find out which of our combinations makes a proton and which makes a neutron. Here’s the cheat sheet:

uuu	2/3 + 2/3 + 2/3 = 2	Positive…but too much for a proton
ddd	(-1/3) + (-1/3) + (-1/3) = -1	Negative, so it can’t be a proton or a neutron. Note: it’s not an electron either–remember, an electron is already an elementary particle.
uud or udu or duu	2/3 + 2/3 + (-1/3) = 1	OK! It’s a proton!
(Just a reminder…the order the quarks are listed in doesn’t matter.)
ddu or dud or udd	-1/3 + (-1/3) + 2/3 = 0	Yes! We have discovered the neutron!

Aha, it’s a proton.

Aha, It’s a neutron!

So, the charge calculations show that protons and neutrons are made of two ups plus one down for a proton and two downs plus one up for a neutron.

It’s possible to have participants glue their protons and neutron quark groups together. A dip on the water cup from the atomic marshmallow project will make a candy piece sticky. However, these sticky messes will need to sit aside for a while to dry. If your participants include young children, you might want to skip that possibility, as a glued-up stack of Life-Savers could be a choking hazard.

Speaking of glue, the same BayCon2017 participants also suggested some ideas for incorporating gluons into our model. To cover the topic of quantum chromodynamics would be a fun challenge, but for the present, those lonely orange LifeSavers we’d set aside as those transient top quarks can be added between the red and white candies in our proton and neutron models to represent the color exchanges among the quarks.

So now we have established that everything in matter is made of tiny (and flavorful) points of dancing energy called quarks and leptons. How can we visualize the true relative sizes of these quarks, protons, nuclei, and atoms?

Poke a pin through a piece of paper and hold it up to the light, then pass it around, so everyone can see how tiny that hole is. Think of that bright speck as an electron or a quark. To be at the same scale, our helium nucleus would be about 3 feet across. A handy meter-stick or yardstick will provide a sense of scale, but for drama, bring out a huge balloon (the 36-inch size). It won’t be edible, but it will be fun to play with afterwards. If that big old balloon is the tiny nucleus, then to build a whole helium atom we’d need a marshmallow about seven miles (ten kilometers) across!

So let’s check back on our atom model from the atomic marshmallow project. It’s mostly nothing, just that airy, fluffy marshmallow. Remember how thin the “shell” of the electron cloud is, and how surprisingly hard it is to notice the tiny nucleus once the two little protons and neutrons were placed inside. Even so, in our model, the protons and neutrons are huge compared with the atom. Imagine how fantastic the resulting candy treat would be–and how many people could enjoy it–if we’d tried to make this marshmallow atom model to scale.

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

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

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.

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.

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

A Cluster of Comets, Incoming & Outbound