Biodiversity and The RAIL Project

Remind Me what RAIL Is?

The RAIL Project is an aquatic ecology project I do with my students each fall at Dakota high school.  The school has a small, sluggish stream on the northeast corner of campus that acts as a drain for several square miles of the Clinton River watershed.  RAIL stands for Riparian Area Integrated Learning.  The "riparian area" of a stream is the strip of shrubs, trees, and grasses along the edges of a river or lake.  Riparian zones are important because they filter runoff and groundwater of sediment and nutrients, and they also slow the runoff so it has time to drop in temperature before entering the water.  These are all good things because too many nutrients will cause algae blooms that lead a stream to become "eutrophic," or full of slime; too much sediment can plug up a stream and stress out native species.  Low temperatures are good because dissolved oxygen exists at a higher concentration in low temperature water, so native macroinvertebrates- not to mention fish- are more successful.

The point of this project is to allow students to determine, by collecting their own data from the stream, whether the ecosystem of the Dakota Drain is healthy or not.  Numerous factors play in here to make this determination, but one of the most important is our calculation of the biodiversity of the river area.

Biodiversity 101

"Biodiversity" refers to how varied the biological community (mix of species) is, in a certain space at a certain time.  Any community, from a stream or forest area, to the suite of bacteria living under your armpit, can have its biodiversity calculated.  Most measures of biodiversity are a function of both "species richness," or how many species there are, and "evenness," or how evenly distributed they are.  More species and more evenness mean higher biodiversity.

The figures below illustrate what is meant by "richness" and "evenness."  Each different shape represents a species in a biological community.  Note that evenness doesn't really refer to the physical distribution of species within the sample area.  It simply refers to the relative fractions made up by each species.  For instance, although the purple triangles in the second box are "evenly" spread out in the physical space, they dominate the community with their numbers.  Thus that community is neither rich nor even.

There are lots of specific ways to calculate biodiversity, but the one my students use is called the "Shannon-Weiner Diversity Index."  The equation is seen below.

In English, the equation says this: "The Shannon-Weiner diversity index of a sample is the opposite of the sum of the natural logs of the percent of each species multiplied by the percent of each species, as represented by the sample."

That's a very compressed way of saying that the index is a representative number that integrates both the evenness of the sample (the percent of each species) and the number of species (which directly influences the percent of each species).  Never mind the steps of the calculation; it has seven discrete steps and is hard to explain without showing a big clunky data table.  An extremely high Shannon-Weiner diversity index is around 3.5, and a low index is anything less than around 2.0.  Generally an index has no unit.

But if you are interested in experimenting with this particular index, you can play around with this Diversity Index Calculator.  (Name and fill in the numbers for a few species, and it will spit out dozens of different biodiversity indices for you.  The one my students are using is the fifth one on the left under the heading "alpha diversity."  It's the second "Shannon" index.)

How do Students Learn to Use the SW Index?

Now students are not exactly familiar with indices or natural logs, and at first they don't really have a clear understanding of what is meant by "evenness."  What kind of work would bring home the concept of biological diversity?

In a word: Candy.

While I was student teaching at Allendale middle school, my cooperating teacher, Kieth Piccard, had his sixth-graders practice finding the SW diversity index with M&Ms, which they of course loved.

Like sixth graders, freshmen love doing work with candy.  I took Kieth's lesson a step further and gave the students four different "biological communities" to study: M&Ms (6 colors), Skittles (5 colors), Reese's Pieces (3 colors), and York Pieces (2 colors).  Each color represents a different species in a biological community.

Each student chose a single Dixie cup with a sample of one of these four communities.  First they simply graphed the community and looked to see if it appeared to be even.

Below are a few typical graphs that students produced for each community.  Some of them chose to do pie charts instead, which is fine because it more clearly illustrates the fractional nature of populations within communities.

It's pretty easy to see whether the communities are even or not.  Reese's Pieces and York Pieces tend to be highly lopsided toward orange and white, respectively.  M&Ms and Skittles are more even, but M&Ms seem to have much more orange and green than the other colors, while Skittles Riddles show a more egalitarian distribution of colors.  (Skittles Riddles, by the way, are puzzling to eat, because the red tastes like green apple, while the blue tastes like watermelon, and so forth.  Students love them.)

Next students had to count the total of the sample, find the percentage that each color represented, and then use the Shannon-Weiner diversity index calculation above to find the biodiversity of the sample.  I only let students eat their candy after they had correctly calculated the index, which presented a pretty powerful motivator.

Students then had to contrast the SW diversity values of the different communities by collecting the values from other students, then graphing them in a single integrated graph like the one to the left.  These are some pretty typical diversity values for each community.

Some students ended up producing the slightly different graph at right.  Notice that here the M&Ms have a higher diversity value compared to the Skittles, and the York Pieces have a slightly higher value than Reese's.

This led students to have discussions about why some of them got different values.  Some students who had M&Ms pointed out that their communities were not very even, which was why some of them found that their diversity value was lower than Skittles, which are more even.  The same was true of Reese's and York.  A few York samples were split evenly down the middle, while Reese's was lopsided.

These comparisons helped students to see that both the number of species (species richness) and the distribution of each (evenness) both determined how diverse their sample was.

The Rub

So here's the rub.  Students will be held responsible for finding the Shannon-Weiner diversity index of the Dakota Drain, based on the vertebrates and macroinvertebrates they find out there.  This will allow them to make a data-informed assessment of the health of our ecosystem.  They already have a sense that our community is uneven, because they are finding dozens of viviparid snails and non-biting midges, with relatively small values from other species.  As for vertebrates, some students have even pointed out that we should not include the 59 Canada geese, 3 red-tailed hawks, or 4 turkey vultures we've spotted, because they are only passing through (migrating) and thus don't really represent our community.  After one more day of data collection, students will begin to compile their data and put together formal reports on the health of our ecosystem.

My students are experiencing what it is to be real ecologists.  The challenges faced by field ecologists are manifold, but the students are consistently showing that they relish the challenges and want to say something meaningful about the Dakota Drain.  Saying something meaningful about reality is ultimately what science is, and it is what every curious person wants to do, whether they know it or not.

Why isn't Pluto a Planet Anymore?

What is a "Planet" Anyway?

Don't scoff, it's a good question.  I have heard otherwise rational and reasonable adults deriding the 2006 decision of astronomers to demote Pluto to "dwarf planet."  Why the demotion, and why the stubbornness of many people- even some scientists- to accept that Pluto doesn't deserve the honorific title of Planet?

Let's go back to the astronomical heyday of the mid-1800s.  Then, everyone had a common and common-sense understanding what a planet was.  It was a large and spherical non-stellar body that orbited a host star in a regular ellipsoidal orbit (only because no perfectly circular orbit has yet been discovered).  But then Pluto was discovered by meticulous astronomical observation in 1930, and it was almost instantly blessed with the honor of planet-hood.  Unfortunately this was probably due more to hype and some miscalculations than any serious categorical consideration.  Upon its discovery, Pluto was erroneously supposed to be larger than Earth.  Being also the first such body to be discovered since Neptune's official discovery in 1846 (unofficially discovered by Gallileo way back in 1612), Pluto made a big splash in the scientific and- perhaps of greater historical significance- the layman communities.  Everyone knew it was a planet.  But this caused the first ripples of uncertainty concerning the meaning of "planet" in the minds of discerning astronomers.

Look at the graphics below.  Notice that Pluto (red) describes a single eccentric orbit in the time it takes Uranus (large bluish planet) to orbit three times.  Even these simple graphics should rub you the wrong way enough to wonder whether Pluto really "fits" in with the other planets.

                Inclined overview                                                          Sidereal view                    

                    Graphic source                                                         Graphic source

It wasn't until around 2005 that a really clear and unambiguous definition of "planet" was established.  Until the 1990s we seem to have had a liberal view of who deserved such a title.  Then in 1992 we discovered exoplanets, large objects orbiting stars other than our sun.  In the twenty-first century we discovered about a dozen dwarf planets orbiting at distances and inclinations similar to Pluto, and usually much more extreme.  Eris, discovered in 2005, is about 25% larger than Pluto; some even make incursions approaching the sun at smaller distances than Pluto, as the dwarf planet Orcus does.

So now we are left with a certain intellectual tension.  All these little dwarf planets, Eris and Haumea and Sedna- along with others- clearly belong to the same category as Pluto.  They are tiny, icy, impossibly distant comet-like bodies orbiting in highly elliptical (squashed) orbits at extreme orbital inclinations (tilts).  Some of them probably arrived in our solar neighborhood by being flung from interstellar space by wandering dwarf stars or even black holes.  They take between 100 and 12,000 years to orbit our sun.

So if these cosmic critters belong to the same category as Pluto, and Pluto is a planet, then these Pluto-like dwarfs are also planets.  To be honest, then, we would have to teach our youngsters a new planetary scheme that would look something like this:

Sun

Mercury

                                                     Venus         (Rocky Inner Planets)

Earth

Mars

Jupiter

                                                Saturn      (Gaseous Outer Planets)

Uranus

Neptune
Orcus

Pluto

                                                                    Eris                       (Dwarf Planets)

Haumea

Makemake

Varuna

Quaoar

Pallas

Ceres

Vesta

Ixion

2007 OR10

2002 TC 302

Hygiea

Sedna

(More coming soon...)

Can you imagine having to know 20 or more planets, most of which are so small and dim that not even a powerful private telescope can spot them?  These outer dwarf planets were primarily discovered with space telescopes anyway.  Can you see the arbitrariness of calling Pluto a planet?  Or at least see that to call Pluto a planet, we would have to do the same for a whole new system of tiny icy balls making up distant, cold regions of space sexily named the Kuiper Belt and the Oort Cloud?

Now we can see what would be a more reasonable definition for "planet" than simply any big thing that orbits our sun.  We are led to accept the following: A planet is a cosmic body that is large enough to attain sphericity by its gravity, sweeps its orbit clean of any other smaller bodies, keeps a relatively non-eccentric elliptical orbit around its host star, whose orbital tilt is similar to that of its solar neighbors.  So we have to be content with only eight planets.

It was thus reasoned by the astronomical community in 2006 that Pluto should be stripped of its designation as "planet" and bestowed a new one called "dwarf planet."  Now dwarf planets are really a whole category of cosmic oddballs drifting in the dark creepy neighborhood beyond Neptune.  They are called "trans-Neptian objects," or TNOs.  Let's look at a few of the most interesting.

Trans-Neptunian Objects

As of right now, there are more than 10 accepted TNOs, along with some comets and asteroids that frequent the same places but are too small even to be regarded as "dwarfs."  Shown below are most of them.

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Most of these TNOs have had their orbits and sizes worked out with some precision.  Notice that Eris is noticeably larger than Pluto, but that many of the dwarfs, such as Varuna, Ixion, and Orcus, are even smaller than Pluto's own moon, Charon.  Notice also that Haumea is squashed; this is thought to be due to its rapid rotation.  The semi-circles around Eris and Makemake are margins of error because their sizes are not exactly known yet.  And we don't even have a proper name for poor 2002 TC302.

Here's rather a more artistic rendition of some of these planets, along with the as-of-yet unmentioned 2007 OR10.  Did you know Pluto has five moons?

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The Strangest Orbit

Don't forget that size and distance are not the only qualifiers for being called a TNO or "dwarf planet."  Most of these bodies also have extremely elliptical and inclined orbits, much like many comets.  Let's look below at some notable ones.

Look at the orbits of Pluto (red) and Haumea (yellow).  Pluto has quite a tilt, but Haumea looks almost ridiculous in its inclination and eccentricity.  Its orbit is also nearly twice the diameter of Neptune's (grey.)

Then look at the orbit of Orcus (blue and teal), again compared to Pluto and Neptune.  It has about the same tilt and eccentricity of Heumea, but it is actually tilted the other way.

Eris (blue and teal) gets stranger still.  Seen to the left, its orbit just barely shaves by Neptune's and even intersect's Pluto's when seen from above, and describes a wide ellipse when viewed along the ecliptic (from the side).  As seen in the right images, its orbit completely envelopes that of all the inner planets.

An artist's eerie conception of a visit to Eris can be found here.

Lastly, Sedna's orbit (red) is the most absurdly eccentric of all the dwarf planets.  The tiny Russian doll of colors at the top right describes the orbits of the inner planets, and also the orbit of Pluto (purple).

Sedna is so outstandingly aloof that its orbital designation is officially "Detached," meaning that it can't quite be said to be faithfully orbiting the sun at all.  If another star were to move by our solar system, it might snatch Sedna away as its own little interstellar treasure.

Seen at left are the orbits of a few of the eight planets (orange, yellow, green, and purple), the orbit of Pluto (greyish), the orbit of Eris (red), and the orbit of Sedna (light blue).

This gives you one of the finest perspectives of the extreme bizarreness of the dwarf planets' orbits.

Graphic source

Don't Complain

If you insist that Pluto is a planet, then you must also accept the other dozen-or-so Pluto-like planets, even far-off Sedna and lonely 2002 TC302.  Of course you do not wish to do this.  No one does.  So don't.  Accept that Pluto, like all the other icy dwarfs beyond Neptune, cannot be designated as a planet and therefore needs to be called something else.  We call it a "dwarf planet," which only adds diversity and complexity to our understanding of the universe.  We are grownups and should accept that not everything- not even the tiny dwarf planets- will fit into our tiny, neat box of biases.

On Radiometry and Climate Change

We Have Cause to be Skeptical

I think that a healthy but open-minded skepticism is generally a good thing.  Open-mindedness without any skepticism results in one's brain falling out of his head (to paraphrase Richard Dawkins), while an impassive skepticism without some intellectual flexibility results in an obstinate and stubborn jackass.  Neither is a desirable state.

I discover a great many jackasses who feel that they need to expose the falsehood of global climate change, especially during the winter when every big storm is apparently proof positive that the theory is false.  Just watch Fox News for examples.  Now I would not mind listening to this debate if it were actually taking place between scientists.  But it is organized in a conspicuously lopsided fashion: 97% of scientists say the climate is changing (and we are probably causing it), while it is almost entirely non-scientists who say it isn't (or at least that it's part of a "natural cycle").  Professional jackass Greg Gutfeld of Fox's The Five has described global warming as "basically dead."  For brevity, I will refer to those who dismiss claims of global climate change as hoaxers.

Why this disparity?  There are all sorts of non-scientific influences that shape our views of physical reality, which I don't care to go into.  Let us suffice by saying that hoaxers just don't know the science and have skepticism toward any belief that fits into their "liberal" schema.  They are especially ignorant of the key evidence that unequivocally supports the proposition, "Global climate patterns are changing, and really quite rapidly.  We're changing them."  Hoaxers seem to fixate on solely the temperature aspect, as though some effeminate scientist in a woolly sweater-vest simply steps out of his office each afternoon, sticks a thermometer in the air, and says, "By George, it's a little warmer today."  Let's get to the evidence.

The Hardest Evidence

In a recent post ("On Radiometric Dating and the Age of the Earth") I discussed how scientists use radioisotopes to determine about how long ago the owner of an organic sample died, or how long ago a piece of rock was molten.  Recall that we can indirectly "count" the ratios of certain isotopes by using a sensitive Geiger counter, or better yet, a gas-chromatograph mass spectrometer (with exquisite precision).*  This method, snappily named radioisotope analysis, has been verified as reliable and accurate since about 1905, when physicist Earnest Rutherford invented it.  One hundred and eight years of critical evaluation and use is not exactly dabbling, and no serious, educated scientist doubts its value and precision (although the interpretation of specific results is always up for criticism.  Just look at the discussion surrounding the Shroud of Turin).

So radiometric analysis of isotopic ratios works.

Let's go to the antarctic.  If you set foot on the south pole, you'd be standing on about 2 or 3 kilometers of glacial ice.  Imagine digging straight down with a very expensive auger and pulling out a tube of ice.  If you look closely, you can make out distinct layers of varying opacity and transparency, and even a layer of soot or smudgy brown here and there.  Each of these layers represents a season, and you can literally trace your way down through history by counting the layers, as in the black-and-white photograph below of a sample taken from 1838 meters deep. (Occasionally the layers mash together and you can't tell them apart anymore except chemically.)

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The Theory Behind Ice-Cores

Now here's the really fascinating thing about glacial ice.  It has water in it.  Water, as you know, is made of two hydrogen atoms and one oxygen atom in the middle.  Oxygen comes in one common isotope, O-16, and two rare isotopes, O-17 and O-18.  O-18 is just a touch heavier than O-16, by two atomic mass units, to be precise.  O-18 is heavier by a great enough degree that the physical characteristics of the water it makes up are actually a little different: the water is denser and requires more energy to vaporize.

Suppose you and a friend were holding a bowling ball and a volleyball, respectively.  If you both tried to shake the balls as fast as you could, you'd find that your friend can shake it a lot faster, with the same amount of energy.  It's like that with water molecules that have O-18; they take more energy to shake up, so they require more heat energy to vaporize.  Follow?

Now your water mixture of H2O-16 and H2O-18 is floating around as vapor in the atmosphere.  As the water finds its way to glaciers and the poles, it often condenses into clouds, which then make some snow.  On the way to the poles, the H2O-18 is preferentially precipitated out into the oceans and continents as rain, especially if the average atmospheric thermal energy is low (it's cool).  But when it's warm, the H2O-18 can stay aloft for longer, because there is more energy to keep it as a vapor.  So in warmer periods, the glacial ice has relatively more heavy water (H2O-18) than it normally would.  (Keep in mind that H2O-18 always represents a very tiny fraction of glacial ice, around 1%.  But that tiny fraction fluctuates with the average thermal energy, or heat.)

In ocean cores we actually see the opposite relationship.  Since in cool periods O-18 is preferentially precipitated out of the atmosphere before it gets to the poles, that water rich in O-18 ends up in the oceans and eventually in the layers of sediment that form carbonate rocks on the ocean floor.  We can measure the isotopic composition of the layers and find that their ratios of O-16/O-18 are inverse to those of glacial ice.  The nice thing about ocean cores is that they go back to around 500 million years, while the furthest we've gotten with ice cores is around 1 million.

I know the last paragraphs were dense and you have to follow them carefully to see what is going on.  But the kicker comes next: We can measure the fraction of O-18 that is present in glacial ice.  We have compared that fraction with known average global temperatures (these are known because we physically measured and recorded them).  And we find... wait... wait... wait... We find that there is a shockingly reliable correlation between O-18 percentages and the average global temperature.  Higher temperature, more O-18.

Extrapolate these data backward in time as far as you care to go, and we find that in the last two centuries... wait... wait... wait...O-18 percentages have risen far faster than would "naturally" be expected.  And they even correlate quite nicely with carbon-dioxide percentages.  We know this because atmospheric gas bubbles are trapped in each layer of the ice, and we can also measure the composition of the gas a mass spectrometer.

You can find articles explaining the methods and interpretations of this work at NASA, the Journal of Geophysical Research, the Earth and Planetary Science Letters, and some publication called Nature.

The Evil of the Double-Standard

I can hear what a balking hoaxer is saying already.  "Of course those publications are going to say global warming is happening- they're written by scientists!  All scientists are in on it."

Yes.  Scientists all say that because they know what the hell they are talking about.

This is like saying, "Of course that professor of mathematics is going to say that six times six is thirty-six.  All mathematicians say that."  Can you see how idiotic this sounds?

Analysis of radioisotopes from ancient glacial ice is not simple or easy.  It takes expensive machinery and very, very, careful methods.  There are all sorts of pitfalls that can lead to bad analysis or bad conclusions.  This is the case in very nearly every science.

What upsets me and makes me feel like my description in my first blog post, is that this discussion takes place most fiercely among non-scientists.  What astonishing hypocrisy.  A hoaxer can dismiss the possibility of climate change with such true smugness, that it causes my fists to clench and they start wanting to punch something.  If the evidence were inconclusive or disproved climate change, scientists would say so.  

Scientists are not really known for being stupendous liars or conspiracy theorists, and I wish they they were just a little more respected by American non-scientists.  The work of chemists, physicists, astronomers, engineers, ecologists, nuclear physicists, pharmacologists, and all sorts of other scientists are rarely regarded with such scrutiny and criticism by the public.  Why the obvious double standard for climate scientists?  As I have said, the reasons for skepticism from a science-illiterate public are too varied and diverse for the scope of this blog entry, but the double standard irks me to an almost painful degree.

Go here for an outstanding over-view on climate change denial, which I may discuss in a future blog post.

Look for double standards and try to expose them; they are the root of much ignorance in this debate.

* Mass spectrometers are used to test professional athletes for illegal steroid use.  Steroids are made in the body from cholesterol, a carbon-based honey-comb shaped molecule that helps cell walls retain their structure.  It turns out that steroids produced naturally in the body have a very, very predictable ratio of C-12, C-14, and C-13.  The steroids produced by pharmaceutical companies are made (accidentally or deliberately) in different ratios.  Analysts look for anomalies in the C-13 ratio of human steroids to see if the number is inconsistent with what is natural.  When it is, the odds of a false reading are something like 1 to 10,000,000,000,000,000,000,000,000,000,000.  That's astronomically small.  This article on isotopically labelled steroid assays explains how false readings can happen.

Exploring Invisible Particles by Visible Observation

Thompson's Cathode Ray Experiment

JJ Thompson did a famous experiment in which he passed an electric current through a glass tube that had a very low-pressure gas inside.  Any gas will do- hydrogen, argon, nitrogen, even mercury vapor.  The tube glows.  He passed the glowing beam through a slit to make a flat stream of glowing particles, which were known as "cathode rays."  Physicists called everything "rays" back then, and there were all kinds of exotic rays which we now know as belonging to the electromagnetic spectrum, or a small set of subatomic particles.  He noticed that when he passed a magnet or a charged set of plates near the cathode ray beam, the particles deflected toward the positive side. (By the way, magnets don't really have "positive" and "negative" ends, but they do influence moving charged particles, because a moving charged particle generates a magnetic field.)  He called the particles "corpuscles" and realized that they were both negative and were less massive than atoms, which led him to correctly hypothesize that the corpuscles were smaller pieces of atoms.  This was contra Dalton, but not completely accurate because Thompson suggested that the corpuscles were floating among a little blob of positive charge; this was endearingly termed the "plum pudding model" of the atom, which was showed by Rutherford to be bunk.

Now cathode ray tubes don't necessarily grow on trees, and neither do their power apparatus.  But I happened to get hold of a set of them, along with their power supply from DHS, courtesy of the chemistry department.

For a simple lab on atomic structure, I wanted students to make some of the puzzling observations that physicists made at the turn of the century, which- although confusing and sometimes self-contradictory when considered individually- can coalesce into a comprehensive understanding of subatomic particles.  Students observed uranium nitrate, uranium sulfate, and thorium nitrate with a small Geiger counter; they measured the radioactivity of alpha, beta, and gamma emitters with a "nuclear scaler" (a very precise Geiger counter); they looked at a simulation of Rutherford's gold foil experiment; and they tested the effect of an extremely powerful neodymium magnet on a powered cathode ray tube.

For a brief video on what they saw, see my YouTube video.

When the magnet is passed along the tube, the electrified gas swirls and quivers, showing the magnetic field lines in tight, alternating bands of brightness.

Students, with minimal help, reasoned thusly:

1.) The glowing substance in the tube cannot be neutrons; otherwise the magnet would not affect them.

2.) It could be protons, but this is inconsistent with what students know about them.

3.) It is probably electrons, because the gas is electrified.

Just one simple way I was lucky enough to stumble upon, to get kids working with subatomic particles on a personal, up-close level.

A Lucky Little Idea

Turning a Lecture into an (Easy) Inquiry Lab

Yesterday I needed my students to walk out the door at the end of the hour, able to name and describe the eight recognized characteristics of life.

Eight- you may be surprised to learn- is a surprisingly difficult number of things to teach to room of fourteen year-olds, in only 59 minutes.  It is hard for them to keep eight ideas in their heads in the first place (me too).

The eight characteristics of life are that, on the species level, all organisms:

1. Are made of cell(s)
2. Reproduce
3. Grow and develop
4. Maintain homeostasis (internal conditions)
5. Respond to stimuli
6. Evolve over time
7. Require energy
8. Are organized (put together in a certain way)

Yikes.

I taught these eight characteristics last year in a strongly didactic fashion.  Students didn't remember more than about three of them.  As an educator, that hurt a little.

Yesterday I did things very differently, because I had a lucky little idea.

I've been collecting and preserving biological specimens of fungi, insects, small plants, even a hummingbird that ran into my sun room window.  Yesterday I amassed my specimens and supplemented them with about two dozen of some common and some truly bizarre preserved organisms from the biology lab.  I placed the jars and my specimens on the lab desks.

When the students came in I delivered my mandate, that they needed to each come up with a list of about eight characteristics that they thought all living things shared.  Their ideas had to be based on observations of the specimens, and their observations might be integrated with things they already knew about living things.

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The Results

I marveled at three results.

First, students were engaged at every moment.  In only a single section did I find one or two loafers; the others were so fascinated that they were almost beside themselves with wonder.  It helped that I placed out a few baffling organisms, such as a few chitons, bristle-worms, yellowish prickly mosses, various Plexiglas-encased insects, some eerily blood-red mushrooms, sea cucumbers, sea jellies, barnacles, leeches, and a few other odd-balls.  Students tended to gather and move about the tables in groups of four to six, and they enjoyed collaborating to come up with ideas.  Many were arguing with passion.

After I gave them about 25 minutes to work, I recalled them to their desks so they could share with the class what they came up with.

Second, the class was able to agree upon 6 of the 8 recognized traits, without ever having learned them beforehand (all except homeostasis and organization).  I then tried to connect their ideas to the "real" eight characteristics of life.  During this discussion, they copied and took a few notes on these eight recognized characteristics.

Lastly, a surprising fraction of students remembered Every. Single. One.

Today I asked students to recall the characteristics of living things, based on this "lab" from yesterday.  They blew me away at what they remembered.  Each section was able to collectively recall each and every characteristic.  Quizzes would honestly be a more accurate means of assessment than just talking, but their memory was still surprising.

All from one lucky little idea.

Inquiry Works Backwards

This is what inquiry does.  Students who create their own knowledge will remember that information.  It is not "known;" it is "understood."  Of course, their self-created understandings need to be validated so they do not become misunderstandings.

Inquiry is "backwards" in the sense that it is the perfect inverse of the traditional science learning experience.  How many times have you had or heard of classes in which students learned the material from a book or lecture, and then went into the lab in order to "apply" it?  My lab was "backwards" in that I threw a task and a tactile, visual learning experience at them, then buttressed it with supplementary discussion and validation.

The Nightmare

If students are not doing something then they are not learning.  If they are not talking to someone then they are not remembering.  If they are not moving somewhere then they are not living.

I see doomed students sometimes.  I see students whose teachers have doomed them before they even had a vague, dark inkling that something was amiss.  

If they are imprisoned in their seats, shackled to an eyes-forward position, lips sewed shut and eyes wired open, scrawling "notes" on a page of paper that they want to tear away, then they are doomed to a hatred of science and discovery, forever.

The Dragonfly Mystery

This week I posed my biology students a challenge.  They were to look at the organism below and try their best to say what it was, using observation, questioning, a testable hypothesis, and an idea for an experiment to test their hypothesis.

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What is this little monster?  A cricket?  Some kind of spider?  

I laid eight small piles of these exoskeletons on the lab desks and had students circle around to look at them.  The ones I provided have a tiny, torn hole just behind the head, and there are no insides.  They range from 2 to 3 centimeters, with the largest nearly 4.5 cm long and 3 across, including the legs.  They are truly hideous little creatures, and at least one girl screamed in each and every class.

What did students observe?  They noticed that they were, first of all, insects because they have 6 legs.

Good start.

They also observed that they are "dead," because they are dried up and not moving.  To this I responded that these were not alive, but it was not really correct to call them "dead."

"Are these real?"

"Yes, these were real organisms."

"Can they bite you?"
"Well, not now.  But they were at one time voracious predators.  Vicious killers, actually."

"Where did you get them?"

"Up north, around Walloon Lake in early August."

"YOU MEAN THEY LIVE HERE?!"

Students most frequently proposed that these are dead crickets, or some, with more precision and subtlety, suggested that these were the exoskeletons shed by growing crickets.

Close, really close!

Finally, in my last hour, a single student working by herself called me over.

"Mr. Nolan, I think I know what these are.  We looked at them in water quality at Seneca Middle school last year."

"What are they?"

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Yes!  These are the shed exoskeletons of dragonfly nymphs just after they had crawled out from the lake- by the millions and millions- in early summer in northern Michigan.  The grown nymphs crawl out of the water; after a few hours the thorax puffs up and splits behind the head, and the massive shoulders of the dragonfly thorax thrust through the leathery skin.  It arches its back, burdened with tightly compressed and crumpled wings, out of the nymph skin in an eerie imitation of a charmed snake.  Then its head arches back and its wings slowly- so slowly- inflate from their raisin-like shape into broad, papery air foils.  Its broad, squat abdomen pulsingly creeps out of the exoskeleton and telescopes into a narrow rod, drying and turning a bright greenish yellow with every passing moment.

Finally, after several hours of painful metamorphosis, the dragonfly extends its wings and clumsily flitter-flutters away.  

This description of the origins of dragonflies is utterly baffling to the students.  It is, at the same time, deeply satisfying to witness their realization that many common critters have similarly surprising origins.

There is a whole galaxy- a whole universe- underlying the commonly held understandings and misunderstandings in the minds of young people.  Show a student this universe and she may recoil at first in disgust, but soon she leans in until her nose is pressed against it and she falls in, without self-consciousness or pride,only the perfect humble joy of wonder.

What students have taught me about grade school science.

The Survey

I teach high school science in Chippewa Valley Schools, on the Dakota campus.  I had six discussions with my students this week, one in each section, and I'd like to share what these discussions have taught me about 1.) How students understand science to work, 2.) How students feel about science, and 3.) How most grade school teachers seem to be teaching science.

I am utterly stunned at what they told me.

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I greased the gears of discussion with an anonymous student survey using SmartResponse clickers, which allow me to instantly collect and display student input.  I asked students a dozen questions about how they think science works and what they think about science, let them respond, then went back through and used their input to have a discussion about each question.  I let them respond either "agree," "somewhat agree," "somewhat disagree," and "disagree;" that way they had to choose a non-neutral response.  Along the way I was inclined to ask them about their previous science teachers.  The questions I asked are below.

1. Science is complete.
2. There is a single scientific method that all scientists use.
3. Science is boring.
4. Not all scientific questions must be answered by experiment.
5. Science is important in my life.
6. I'm no good at science.
7. An experiment is any time you do something without knowing what the result will be.
8. Scientific conclusions don't really change over time.
9. Science is a collection of facts.
10. If a study does not reach a firm conclusion, it was not a good study.
11. A theory is a vague scientific idea that doesn't have any strong evidence.
12. Creativity is important in science.

I'll point out a few of the most important things I learned with this exercise.  As an educator, I think some are encouraging, but others are, well, disturbing.

The Results

1.) Very few students consider science to be complete, because "then there would be no questions left," and "there would be no point to science," and "every time we learn something, it opens new questions."  This are all, I think, common-sense responses.

2.) Disappointingly, about 75% of students agreed that there is only one scientific method, and here is why: Science educators teach "the scientific method," and that little article "the" causes a lot of misunderstandings.  Although scientists have common habits of mind, ways of thinking and asking questions, ways of investigating, and ways of analyzing, they really use a wide array of methods.  For instance, an experiment is not always necessary to do science.  Scientists also frequently backtrack and start over at an earlier point in the scientific sequence when they encounter problems.  Science educators should be teaching "scientific methods," not "the scientific method."

3.) About 20% of my freshman agreed that science is boring, and I asked why.  Here is what they said: "The only science I've ever done was in worksheets and from the book," and "I never learned how to do science."  When I asked how many students have mostly experienced science through worksheets, nearly every single student raised their hand.  I was at first so appalled at this that I almost lost my place in the lesson.

4.) and 5.) Most students agreed with these.

6.) This one really struck me to the heart, because about a third of students agreed that they are no good at science.  Whether or not it is true (it may be), I used this to make an important point.  Musicians: The first time you played the guitar, or the piano, or the oboe, or harp, or harmonium, were you "good at it"?  It took me months and months of work and some degree of persistent discipline just to be able to honestly say "I play guitar."  It is much the same with science.  I told my students, "When you walk out of here in June, you will be able to do things that you never imagined you could do.  You will feel so powerful because of what you can do.  That's what science is: Power."  The moment of reflective silence that followed almost made the air tingle.

7.) Most students agreed with this, but we just discussed the definition of an experiment: A way to test an explanation about the world.

8.), 9.), and 10.) These ones are common misconceptions, but most students disagreed with them.

11.) I was shocked when 70% of my fifth hour agreed that a theory is an idea without any strong evidence.  I pointed out that, strictly speaking, the existence of atoms is a theoretical conjecture.  

"Do you believe in atoms?"  

"Of course."  

"But atoms are only a theory."  

"But they definitely exist!"  

"So a theory is more than just a vague guess."

12.) Some students suggested that in order to do science, you have to be able to use your imagination to come up with experiments or ways to analyze data.  I was happy to see that most students recognized that not only artists, musicians, poets, and dancers need to be creative in their jobs.  "Creativity" can become manifest in other areas.

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What does this mean for young people?

The most disturbing and appalling thing I learned here is that many students had no idea that it was possible for them to "do science."  When I discussed the RAIL Project with them, one of them honestly said, "Wait, you mean that we are actually going outside to do work?  I didn't know that you could do science outside."

What does this say about grade school science teachers?  It means that their students are not doing science.  Their students are doing worksheets and memorizing definitions instead of creating knowledge.  It means that educators in the lower grades are failing their students by cramming science into a tiny, dry box instead of opening students to the world.  It means that American teachers have efficiently produced a generation of young people who have negative emotional associations with science and a feeling of helplessness in the face of scientific challenges.  It means that millions and millions of young, bright people are falsely convinced that they are no good at science, that science is boring, and that theories are only guesses.*

On a bright note, there are positives for my classroom.

It means that students are walking into my class exposed to a brand-new outlook on science.  It means that the veil is falling from their eyes, and they are experiencing an open-mindedness toward physical reality that was once closed by the narrow halls of elementary and middle school science wings.  It means that they will start reading books like Survival of the Sickest and Why Evolution is True, Your Inner Fish and A Sand County Almanac, The Hot Zone, Silent Spring, Sibley's Field Guide to Birds.  It means that some of them will choose to be scientists.  It means they will do science instead of having me do it for them.  It means they will ask their own questions, not just answer mine.

Give them the rules and they will play the game.  Give them a blank board and they will create their own.

*Of course, not all grade school teachers are responsible for this, and I don't mean to paint with too broad a brush.  My cooperating teacher at Allendale, Keith Piccard, is doing incredible things with his sixth-graders and his own RAIL Project.  I consider him the ideal and model of exactly what a grade school science teacher should be.

The Great Mystery Tube Lab

What is a "Mystery Tube?"

Simply, a "mystery tube" is a closed pipe with four ropes emerging near the ends, on opposite sides.*  Pull a rope, and any other rope(s) that are out will get pulled back in.  It doesn't matter which rope you pull; any and all ropes already out will mysteriously slither inside.  It can be inferred that the ropes are connected inside, but you can't see how. See my Youtube video for a visualization and explanation.

Students watch this strange phenomenon and are immediately fascinated, because the strings seem to behave in contradictory fashion.  Sometimes students are tempted to say, "I know what's going on inside," even before they have been able to make any careful, systematic observations.  "They are tied in a knot on the inside."  They are always wrong when they say this, because what is "obvious" in this case is incorrect.

The Mystery Tube

How I Use this in the Science Classroom

I am thoroughly convinced of the importance of "inquiry" in science education.  "Inquiry" simply refers to allowing a student to make her own observations, pose her own questions, launch her own investigations, and come to her own conclusions.  Inquiry is opposed to "Didactic," which is when an educator is merely a transmitter of information.  This is not to say anything against didactic lessons, only that students are forced to passively experience them rather than be actively engaged.  I use some elements of each in every lesson I teach, but I try to lean toward inquiry.  Students have more control and choice in these lessons, which is positively correlated with both salience (perceived importance) and motivation.  Inquiry can be applied in any subject, but science by its nature is especially well-suited to inquiry.

This lesson is an excellent introduction to the nature of science and scientific methods.  The tube is mysterious enough that it engages students for two whole class periods, and with proper guidance, students can see for themselves how they should conduct an investigation to understand the workings of the tube.

The Lesson in a Nutshell

Day1:

I begin by pointing out that all scientists have common habits of mind, ways of observing, and ways of answering questions about the world.  These habits are collectively referred to as "scientific methods."  Now most students are familiar with "the scientific method," (observe, question/hypothesis, experiment, analysis, conclusion) but I make sure that they recognize that there are other ways to do science that don't fall strictly in line with "the scientific method."  For instance, sometimes scientists will hopscotch from one step to another, or not conduct what is considered an "experiment."

I have a volunteer play with a tube in front of the classroom, to immediately hook students.  I give each group of two partners one mystery tube to observe for themselves.  Then I give each student a data sheet that includes spaces for a single question about the tube, how they will make observations, the observations themselves, a space for a drawing of the inside (their hypothesis), and how they could test their hypothesis. 

This is a good opportunity to point out that a hypothesis is not simply an "educated guess," which is the stock definition provided by unimaginative grade-school teachers.  How is a fifth-grader supposed to make sense of what an "educated guess" is?  Their drawing is a proposed explanation for how this system works, and the explanation can be tested.  This is what a hypothesis is.  Some of their hypotheses are shown below.

A                    B                    C

D                           E

Some students suggest that there is a "device" holding the strings together inside, as is seen in hypotheses B and D.  In B the device is fixed while in D it lets the strings slide freely.  B and C both involve knots.

After they have drawn their hypothesis, I guide them toward how they may choose to test it.  This test serves as their "experiment."  I don't discuss variables or the proper definition of an experiment here, only that an experiment is how scientists test their proposed explanation.  Most students suggest that they could cut the tube open, but this would really just be making more in-depth observations, so it is not an experiment.  It is also not allowed.  Eventually some students suggest that they could build a small model with common materials, such as toilet-paper tubes.  

It is at this point that I collect the tubes and explain to students how they will test their hypotheses, by building small models using string, tubes, and any other materials they think they need.

Day 2:

Students come in on day 2 excited and ready to test their hypotheses.  Some even build models at home on their own initiative, so they were already able to test their hypothesis (they like to brag about this).

I let each group take a toilet-paper tube and two or three strings of yarn already cut to a length of about 8 inches.  I also provide paper clips for the "device" some of them proposed in hypotheses B and D, scissors, compasses, and wooden skewers to help them punch holes.  I give them the tubes again so they can compare their model's behavior with that of the tube.

Students have 35-45 minutes to test their hypotheses, and I leave all the specifics of their models to them.  Some students stop after their first test and realize that their hypothesis is completely bad, such as A shown above.  Some are at first convinced that their hypothesis is good based on their model, but they just need to make a few minor improvements (such as where the knots are located), as in hypotheses B and C.  Others are able to design a model that behaves 100% like the Mystery Tube, which indicates that their hypotheses are "good."  D and E were good hypotheses.

Discussing the Nature of Hypothesis and Certainty

I discourage students from considering their hypotheses "right" or "wrong," but rather "good" or "bad."  Their hypothesis either explains the observations (it's good), or it does not (it's bad).  I point out why this distinction is important: I (sarcastically) hypothesize that there is a tiny man inside the tube, who pulls the strings in a certain way when I tug on the others.  This hypothesis cannot really be proven to be "wrong," however it can be shown to be "bad" based on what we know about humans (they can't fit in a 1.75 inch PVC pipe).  Conversely, a hypothesis that works- as illustrated by experiment- can be "wrong" even though it is "good" in that it is consistent with observations.  D and E shown above both work perfectly, even though the "right" one is D.  We could talk all day about these distinctions, but after some discussion, students understand what is meant by a good or bad hypothesis and that a good hypothesis is "possibly right," while a very bad hypothesis is "not possibly right."

I grade students on participation, because some of them work very hard to improve the model for a hypothesis that is pretty bad.  This shows persistence to understand the tubes.  I want them to know that I value their investigation, even if they never developed a "good" hypothesis (almost all of them did).

The photographs below show the actual arrangement inside the Mystery Tubes, as correctly hypothesized by some of the students.

Should I Tell Them?...

By the way, I never reveal to students exactly how the tubes work.  A practical reason is that I don't want their younger siblings or friends to come in next year already knowing how it works.  The educational reason  is that I want them to understand that "the best explanation" is sometimes as far as you can get in science, and very often a hypothesis can in no way be "proven," that is, known with absolute certainty.  An epistemic philosopher would have a lot to add here, but an epistemic philosopher I am not.  Enjoy!

*Credit for the idea for the lesson plan and Mystery Tube design go to Dr. Pablo Llerandi-Román, of the Grand Valley State University geology department and instructor of the course Earth Science in Education.