A Sense of Scale

Today we covered three small topics.  It's my last day with the 1-2
graders (I will rotate to the upper graders), and also the last day
before Christmas vacation, so I tried to squeeze in several fun things
and also answer some of the questions which arose last week.  So we
didn't go super-deep in any one topic, but we had a blast. 

We started with a movie: the ten-minute 1977 classic Powers of Ten by
Charles and Ray Eames.  I wanted to show this movie because the kids
had many questions last time, when I mentioned galaxies but didn't
have time to really explain them.  This movie steadily zooms out from
a person on Earth to show how big and how far apart astronomical
objects are.  The movie then zooms progressively in to show the sizes
of microscopic things.  (Note: if you want more snazzy modern special
effects you might try the more recent Cosmic Voyage, but Powers of Ten
feels more intense.)  I stopped the movie many times to answer
questions as they arose, but eventually there were too many questions.
We had four 3-4 graders in the room, and I will be doing astronomy
with them in the spring.  It looks like showing this movie would be a
good way to start my three months with them.  They could generate
questions, and we could take our time answering them.  The best
question today was, "How do we know all this?" and I hated not having
time to give a real answer.  My three months of astronomy with the 3-4
graders will be the answer to "How do we know all this?"

I then showed a website for visualizing the sizes of things, where you
control the zoom. This is a great site for showing how much
bigger the Sun is compared to Earth, how much bigger some stars are
compared to the Sun, etc.  But be warned: they do NOT show the space between these objects, so don't be fooled.  The space in between stars
is VERY, VERY BIG compared to the stars themselves. 
Apart from that, it's a great tool.  (One caveat: I did not zoom out all the way to the "estimated size of the universe"...there is no estimated size of the universe.)  Exploring this site also generated many questions, so that may also be a good icebreaking activity.  Because you can zoom in as well, it could even be a good icebreaker for life sciences as well.

A few more links for interested parents:

• http://www.nikon.com/about/feelnikon/universcale/  is a similar idea as the previous link but with a different feel.  It's worth checking out, but it mostly focuses on microscopic things rather than astronomical things (it has a few mistakes too.

• http://www.wordwizz.com/pwrsof10.htm is another site along these lines; it's not as pretty as the previous two, but it does properly show the vast space between things.

• http://www.powersof10.com/ is a site (currently in beta) by the Eames Office. I just discovered while gathering links for this post, so I can't say much about it other than it looks promising.

Activity number two was understanding orbits with a donutapult demo and play with the coin funnel.  Since I've blogged about this before, I won't describe it in detail here.  If you'd like to read about it, search for these terms (donutapult and coin funnel) in this blog's search box.

Activity number three will be the next blog post.

Mystery tubes 2012

This year I have a new title (scientist in residence) at Peregrine School, and a new format: every Friday morning with grades 1-2 for three months, then with grades 5-7 for three months, then grades 3-4 for three months.  This should allow me to go much further in depth with each group, and to facilitate really substantive projects on their part.  Today was my first day with the five first and second graders, and to break the ice I brought some "mystery tubes" which are basically like the one shown on this short video.

The students got their hands on the tubes, did any experiment they wanted to (short of looking inside the tubes), and drew what they thought was inside.  Most students went through a couple of iterations as they realized that their first model wouldn't reproduce their observations.  When a student was satisfied with his/her drawing, I brought out toilet paper tubes, strings, beads, etc so they could build a model and show that it behaved like the real thing.  The point: science is about building models (usually mental models rather than physical models), and this activity allows us to practice many aspects of this in one session, including thinking of experiments to test the model, performing those experiments, generating predictions from the model (hypothetico-deductive reasoning), and comparing the results of the experiments to predictions generated from the model.  Furthermore, since I never allowed them to look inside the tube we had ample opportunity to discuss how science is less about knowing the right answer than about the process of finding answers.  After all, nature never tells us the right answer directly.  Kids at this age are very much in the mode of gaining knowledge from books, but it is worth making them stop and think about how every bit of the knowledge in books was, at some point, figured out by someone who had to figure out by reasoning and then convince other people that it was correct. 

You can also read about the way I did this activity with mixed ages (grades 1-6) last year.   A note for teachers using this activity: it took much more time this year, 45 minutes, because the 1-2 graders did not have the fine motor skills to easily build their little toilet-paper-tube model with strings and beads.  With mixed ages last year, it seemed as if the young ones contributed equally intellectually, but the older ones probably did the actual tying of strings and beads.  And the 45 minutes was with two adults helping four kids!  If you try it with a larger group of 1-2 graders, you'll have to bring full-size materials. I do this activity with college students (who find it interesting and beneficial) so this activity is remarkable for the range of ages who find it suitable!

I learned something from Teacher Marcia too.  With five minutes remaining in the period, I wanted to have a wrap-up discussion with the kids.  She showed me a way to make kids pay full attention to the wrap-up discussion rather than surreptitiously keep working on their model: move them from the material-strewn desks over to the rug where they listen to stories etc.  This was brilliant.  Now if I can figure out how to do this with college students, I'll be set!

Liquid nitrogen ice cream

For the potluck on the last day of school, I made ice cream using liquid nitrogen.  Basic recipe: milk, cream, sugar.  For strawberry ice cream I added vanilla plus strawberry puree, and for ginger ice cream I added ginger syrup and ginger bits.  The LN2 cools it down real fast.  It was a big hit.

Liquid nitrogen

Last Friday (May 25) Vera visited Primaria and brought liquid nitrogen, which is as cold as Uranus or Neptune.  Pluto might warm up close to liquid nitrogen temperatures during its summer, but in its fall it gets a lot colder and nitrogen is thought to freeze out of its atmosphere onto its surface.  Fun stuff you can do with LN2 includes: (1) freezing a banana hard enough to use it as a hammer and pound a nail into a piece of wood; (2) make a balloon completely flaccid as the air inside cools...blow on it to warm it up and it pops back into its normal state; (3) freeze a racquetball and watch it shatter when thrown on the ground; (4) make ice cream instantly (Vera didn't do that one); (5) freeze a flower and see how it shatters when frozen; (6) freeze anything the kids suggest.  Vera also related it to the infrared camera I showed the kids earlier this year.  What color would LN2 appear on an infrared camera?

This is also a great demo for elementary (and older) kids, although we haven't done it there yet.   Keep in mind, it is a demo, not a hands-on activity, although you can definitely involve the kids in thinking of what to freeze next and making predictions for what will happen,

Icebreaking Activity: Mystery Tubes

Today was my first day with the elementary kids.  This is a brand-new school with about 22 students total in grades 1-6, and there is flexibility to work with age-segregated or mixed-age groups.  I did the mystery tube activity (with extension #1) because it's a good icebreaker, and it naturally comes first because it addresses the nature of science.  (By the way, I discovered this activity when the folks from http://undsci.berkeley.edu/ came to UC Davis and conducted a workshop on science outreach.  Their website is worth a look, especially the diagram showing the real process of science, which is the exact opposite of the cookbook 5-step procedure you see in most textbooks.  But maybe that's another post.)

I chose mixed-age groups because I was afraid the younger kids would struggle with it, and could use assistance from the older ones (the activity is recommended for grades 6-16, but I was pretty confident that grades 4-6 could handle it well).  There was a fair amount of awkwardness because everybody was new to the school, and there was no established pattern of working in groups; some students still didn't know some other students' names!  Considering that, it seemed to go fairly well.  While some younger kids did struggle, a few other younger kids just nailed it. So while I still wouldn't recommend it for a group younger than 4th grade, it was eye-opening to see some really good results from individual 2nd-graders.  At the same time, I have to admit that there wasn't much discussion of concepts like "Test results sometimes cause scientists to revise their hypotheses."  We were doing those concepts, but it was hard to discuss them in these mixed-age groups.  In the future, if I have mixed-age activities I might think about how to "debrief" the older kids separately afterward, to discuss how they can take what they learned in the activity and generalize it to make it useful in other parts of their studies and their lives.

A few tips for those wishing to do this:

• have a bucket of threadable beads ready.  These are handy for tying onto the strings in the models so they don't slip through the holes in the toilet paper tubes, as well as for connecting the strings in the interior (in any way they wish; I don't hint in any way that they should use the beads to connect the strings, but they get used because they're handy).

• I made tubes with different types of connections in the interior, because often when two groups of scientists think they're doing the same experiment, they're not really, due to some confounding variable.  So I think having all tubes identical subverts the process-of-science aspect of the lesson, and this came in really handy when students begged me for the answer (I honestly didn't know the answer for each individual tube) or thought they figured out the answer and tried to tell everyone else rather than let the others experiment more.
• If you suspect groups might not function well as a group, it's ok to forget about "sharing findings" and the like. I wish I had more toilet paper tubes because many students wanted to make their own model, and I think that would have been better than forcing students to build models in groups. It's hard to wait for your turn at improving the model! 
• We did it in 3 rotations of 20-25 minutes each.  I think it needs a bit more time than that, like 30 minutes.

Update: it may not have been clear why I don't want to tell them the answer. The activity is a miniature version of the process of science.  Students build and refine a model of how the tube works.  In the same way, when scientists build and refine a model of how the Sun works, for example, there is no way to reveal the correct answer.  They can only think of better and better ways to test the model, and improve the model if any test shows a problem with it.

Most discussions of the process of science focus on the mechanics of it.  Students pose a question ("How does this thing work?"), suggest hypotheses (saying "I think there's a knot inside" and drawing a diagram of where and what kind of knot), and then test their hypotheses ("If I pull here it should...").  This is all great, but teachers usually present it in a context where the correct answer is already known, or revealed at the end.  If the answer is already known ("today we will measure the density of water"), the activity turns into a dry, dull exercise.  If the answer is revealed at the end, the whole idea of science as an ongoing process of inquiry is subverted.