Human Mitosis Model Activity

A quick activity that I did when I had a little time left over at the end of a class. Could be developed into a more formal activity if you have the time or inclination to plan it. I did a skeletal version, but I'm thinking next year I will make it a central activity and get more elaborate with it.

Students act the parts of the major players in mitosis. In this model, I used the classroom walls as the cell membrane - not enough students to have a human cell membrane, but that would be a nice addition.

Two girls represent sister chromatids of a maternal chromosome.

Two boys represent the sister chromatids of the paternal homolog (yes, they were upset at playing the role of sisters, and refused to touch each other (lock arms) to represent the centromere connection - boys!).

A group of students form a nuclear membrane around the chromosomes.

Two students stand outside the nucleus to represent the centrioles that will migrate to the poles. I used twine to represent the spindle fibers.

Teacher calls out the phases of mitosis, students enact the events.

Prophase - nuclear membrane "breaks down" (students disperse into the "cytoplasm" of the cell). In a real cell, the chromosomes would become visible, but in the model the students can't exactly be invisible and then appear - Oh the limitations of models!

Metaphase - chromosomes line up along the equator (middle of classroom), centrioles migrate to poles (front & back of the room).

Anaphase - spindle fibers attach to centromeres (students have to use hands for this part), begin to pull chromatids toward poles.

Telophase - nuclear membranes re-form around the chromosomes at each pole, forming two new nuclei. Each nucleus now contains an unduplicated paternal chromosome and an unduplicated maternal chromosome.

Repeat. Try to make it a smooth uninterrupted process, fluid. It's a nice reinforcement of the concepts. Have students as much as possible plan the activity. Plan ahead and have students wear color-coded clothing for an even more dramatic effect. A nice open space obviously helps.

Mitosis Models With Pipe Cleaners

Ok. My prepared slides of mitosis are missing, so I had to scramble to find an activity to do on the subject with my classes. I remembered seeing some students from years past doing models of mitosis with pipe cleaners to represent (obviously) the chromosomes.

Now, I had thought this was a pretty lame activity - look at the pictures in the book, reproduce the stages of mitosis (P-M-A-T) with pieces of pipe cleaner and move on. Nonetheless, I needed some kind of activity and I didn't have much time to look for something else. So I threw together the materials and headed to class. Explained the procedure. Showed students the pictures in the book (we had already discussed the cell cycle & stages of mitosis, read the chapter & answered questions, etc), made a few suggestions like only using one or at most a pair of chromosomes, identical colors for sister chromatids, different color for the homologs, etc.

I was wrong about the lame thing. They really struggled. Because they weren't just copying the pictures in the books, they had to think about the process and sort out how the chromosomes separated and figure out how to model that with real materials. Early on, some students were using different colors for the "sisters" (I don't care if they know the term chromatids at this point. So I let them just shorten it to sisters. Having told them this, they proceeded to use the term sister chromatids anyway!). Others were using the same colors for both chromosomes in a homologous pair. Some of their models ended up with daughter cells having pairs of sister chromatids rather than a homologous pair. I got questions like, "How long should the spindles be?" All these issues had to be sorted out. The funny thing is, they had no trouble answering questions from our discussion & the textbook that could be answered by simply memorizing information about the process - "What happens in metaphase?" e.g.) But those were just words. They didn't actually have a mental model yet of the process.

A more disturbing problem (for me looking at it from a pedagogical standpoint) was a sort of intellectual laziness, for lack of a better term. I had given them the option of using one chromosome or a pair of chromosomes in their models, and emphasized repeatedly that we were making a very simplified model, and that different organisms have any number of possible chromosome numbers, and whatever happened in our model to a single chromosome, happens in the real world to all the chromosomes in a cell. We have mostly talked about humans and our 46, but some organisms have only 2 chromosomes, others over a hundred. (Bacteria have a single chromosome, but they don't divide by mitosis). The problem came when I illustrated metaphase on the whiteboard using 3 chromosomes - just to use a different number from theirs. Afterward I walked around, and several students had placed - you guessed it - three chromosomes in their metaphase, even though they only had one or 2 chromosomes in their prophase! They were looking for someone to just tell them what to do without investing any more thought than absolutely necessary. I might not be so critical if they had at least asked questions about it before making the mistake, but they didn't.

I can see two important things happening in this process. First, they are clarifying their thinking about a fundamental process - and it's good that I see the difficulty now rather than later when we move on to meiosis. Secondly, they are learning how to make models - a skill in itself. The whole concept that in a model we often need some way of indicating that two things are either the same (sister chromatids) or different (homologous pairs) was apparently a new idea for some students.

I highly recommend this or a similar activity for students learning mitosis & meiosis. If I have time, I will do a more formal write-up with lab sheets and post it all later.

Curriculum & Text

After careful consideration and review, I believe that the rest of my course sequence pretty much follows textbook units, though not necessarily in the order presented in the textbook. I will therefore only need to make minor modifications. For example, I'm deciding whether to follow mitosis/meiosis with all the DNA material -structure, replication, etc., or with basic cell biology - structure, movement of materials, biochemistry. It makes sense to cover this material before DNA, but it also make sense to teach DNA after mitosis/meiosis. What a dilemma. I've posted the current version here.

I've also reached the conclusion that the Holt textbook is useful almost exclusively as a source of great photos. It's nearly impossible to read the text and come away with any understanding of what's going on. If you read a single section or paragraph, it might make sense. But the sections are not constructed well, each one seems to read like a stand-alone encyclopedia or dictionary entry. The big picture is hard to see, the connections between ideas are not well developed. The chapters are also jam packed with topics. I find it just too complicated to tell student not to worry about Topic X, ignore questions 3, 7, 15, etc. I nowrealize how difficult it is (for me at least) to evaluate a text without actually using it in a classroom setting. When looking at the textbooks last year, I simply opened to a few isolated sections and read them, trying to imagine how difficult it would be for students to understand the section. My evaluation strategy seems to have meshed well with the textbook style, and I wonder how many textbook evaluators fall into the same trap.

I am also using as a review book the Amsco publication: "The Living Environment: Biology" by Rick Hallman. This is almost the polar opposite of the Holt text - not many pretty pictures, not many diagrams or sidebars, but a lot of text reasonably well written. Hallman does a nice job of writing a cohesive narrative for each chapter and each major topic. By limiting pictures and making the ones that are present black & white, the eye/brain can really focus on the reading and following the narrative. The Holt text is a visual nightmare, from the pictures to the sidebars - tips, reviews, objectives, real-world applications - to the overly visually stylized text itself, full of colorful numbered lists, colorful bulleted lists, colorfully highlighted vocabulary words, - it's a disaster!

And I don't buy the notion that the "MTV generation" needs this kind of stimulation. That kind of visual bombardment may be great for entertaining or holding attention, but I simply do not believe that it allows for, much less promotes, critical thinking.

Rethinking Curriculum Sequence

There is of course a downside to any attempt at circumventing the tedious and traditional approach to teaching biology "from the ground up." There simply aren't any biology textbooks that are at the same time constructivist and content rich, at least not any that I have seen. There was a big discussion within the biology teacher's listserv from NSTA (members only, manage listserv subscriptions from your member page) that I subscribe to regarding textbooks vs. inquiry. Here's an excerpt from one that got me thinking about the ridiculous amount of work I do this year:

I teach high school now, but in my student teaching year I taught a 6th grade science/math core using FOSS kits. We didn't have a textbook at all. I loved the FOSS kits and all of the cool equipment, but the content support was lacking. Without a textbook, I found myself writing little articles for my students to take home and read. That was a LOT of work, I tell you!

Sounds like me now trying to teach "outside the textbook" and searching desperately for materials or in many cases writing my own materials to support the concepts I teach in the classroom. It's not that the textbook I have doesn't cover the concepts I teach, it's just put together the wrong way. There's a separate chapter, for example, for cellular reproduction and heredity. The chapter on meiosis & mitosis precedes the chapter on heredity, and of course the chapter on heredity assumes knowledge of those concepts and incorporates modern understanding into Mendel's model. I chose to teach heredity as much as possible from Mendel's perspective, from a time when chromosomes and DNA were unknown. Thus I can't assign students to read the chapter in the textbook on Mendel, because they will be totally confused by all the meiosis/mitosis vocabulary. In hindsight, without the aid of a textbook to guide me and the students through such a process, I would not do it this way again. It's just too much information for me to try to pull together from too many sources, not to mention trying to structure a sequence of lessons and activities that would allow students to reach some of the conclusions Mendel reached. Finally, I believe the "right way" to do this would involve students actually growing some plants (like Wisconsin Fast Plants, e.g.) and recording some actual data. Of course even "fast plants" are too slow for a regents level biology class, where Mendelian heredity should be prior knowledge already (from middle school).

What this example illustrates is the power of textbooks to dictate curriculum. Developing our own curriculum is overwhelming. Students need more than good classroom instruction - they need enrichment materials, study guides, reinforcement activities. These materials should be aligned with classroom instruction for maximum benefit. Given these needs, teachers make the logical choice to align their instruction to the materials available to them, even if those materials are poorly suited to state standards and good pedagogy. The alternative is to spend 12 hours per day including weekends developing materials and still feeling like you are coming up short.

I will be revising the sequence and structure of my instructional plans in the coming weeks, which I will post & comment on when the changes have been made.

Final Thoughts on Natural Selection...

...before moving on to heredity.

I don't believe for a moment that most of my students have mastered the concept. I know from a test that was given (using questions from old regents exams) that they are struggling to pull all the ideas together. This is not exactly unexpected. Evolution and natural selection take a while to sort out, the idea of change occurring over generations is difficult to grasp. A few students have latched onto Lamarckian explanations, and can't seem to get past the idea that adaptation happens to individuals, that it is somehow a matter of individuals "getting used to" environmental conditions.

I don't know where the Lamarckian ideas come from, it must be somehow intuitive, because I purposely didn't teach Lamarck's theory for fear of suggesting an idea that some of them might find attractive. I have now addressed the issue since it did come up in their analyses, but it will take some more work to get students past the idea.

I plan to weave evolution and natural selection into other topics whenever possible. I did take advantage of the discovery of Homo floresiensis to discuss human evolution briefly, although I hadn't planned on addressing human evolution until after we have done the heredity/genetics component. That way when we discuss DNA evidence of the chimp/human relationship, it will be more compelling. A full unit on modern synthesis, history of life on earth, and human evolution are scheduled for early next year, after we complete heredity & cell bio.

Finches' Beaks

New York State's Regents Exam for Living Environment includes questions that are based on 4 required lab activities. One of those labs is called The Beaks of Finches and is supposed to be a simulation of Natural Selection.

I wasn't impressed with the lab.

Let me first describe the idea. I would post the actual lab activity, but it is copyrighted by NY State and we are explicitly forbidden to distribute it except to NY State personnel involved in teaching it. In fact, the state does not make it available to us electronically, instead we must request hard copies directly from State Ed., so I wouldn't be able to post it anyway unless I scanned it myself.

There are other similar versions of the activity around: This one at Access Excellence is almost identical to the New York State version minus the student worksheets (It's the format and exact nature of the questions on the lab worksheets that are unique to NY State).

Basically, you need about 12 - 16 different grasping devices - tongs, tweezers, pliers, etc. - and 2 different kinds of seeds. I used extremely small lentils and fava beans. Students work in pairs, and try in 30 seconds to gather enough seeds to survive from a plate of seeds at each table. Average 13 seeds per round and you survive. Those who do not survive the first round (small seeds only) "migrate" to another island and try their beaks at larger seeds. In the second round, competition with another group is added to the activity. Anyone who doesn't survive the second round is "extinct."

The problem I had with both of my classes was that clearly technique was the deciding factor in surviving rather than the type of beak. I had small tweezers that come to a sharp point and large scissor-style tongs with wide flat tips (beaker tongs) and short heavy stubby pliers and variations on all those basic types. Absolutely no trend emerged that would allow students to see a connection between the type of beak and success in the struggle to survive. Granted, it is important for students to know that behavior (technique) can also be subject to natural selection, but that seems to me to be a finer point to stress AFTER students understand the basic concept as it relates to physical characteristics. Anyway, the activity is called Beaks of Finches, not Techniques of Finches. On that score, the activity fails miserably. Although there may be some interesting higher level discussions that could come out of this activity, for a demonstration of the basic principles of natural selection I would look for other simulations. It is probably not a coincidence that the June 2004 and the August 2004 Regents exams have not a single question about this lab (the other 3 required labs are represented in the questions). Sadly, I can think of some ways that it might have worked better, but teachers are warned to do the labs exactly as they are written or else the students may be disadvantaged by the way the questions on the exams might be worded.

Student Blogs?

I haven't been able to get my student blogs off the ground yet. There are two issues to consider. First, I need to have meaningful assignments that I can put up on a regular basis. This requires a considerable effort in terms of time and ingenuity. It isn't that easy to come up with ideas that actually require a blog and couldn't be done more easily in another format. Obviously there are things I want students to view on the internet at some point in time, but we haven't got there yet and assigning students to view content on the internet in and of itself doesn't require a blog response. The central challenge is to use blogs to foster strudent communication & collaboration. I may need to re-think my original model and go toward a voluntary blog assignment for now, allowing each student to set up his or her own personal blog. My original idea was to have a class blog and allow students mainly to respond to questions I post. That no longer seems a workable format, given already the time I spend planning and setting up labs and so on.

Secondly, there's the logistical matter of introducing students to the blog concept/format and training them in how to use it. This is actually easier if I allow students to have their own blogs. One problem with the original idea was that comments are uneditable, which gets to be a problem since I want students to work on grammar and spelling and the like.

In writing this post, the solution is becoming clearer. I will work on helping students set up their own blogs on a voluntary, extra credit basis. Then teach them how to use it, what it's purpose is, and allow them to submit certain types of homeworks in blog format. I'll think about how to encourage comments between students, and offer feedback as well. Stay tuned...

Student Conceptions: Origin of Species

Doing a search for ideas on teaching evolution with a constructivist approach, I happened upon this article by W.W. Cobern which makes the point that I alluded to in an earlier post on the importance of tapping into students existing conceptions of reality. I don't like to throw too much jargon around and frankly I don't have much of a memory for pedagogic gobbledygook. Nonetheless, the article reminded me of some of the constructivist principles that underpin my instincts and reminded me of the conceptual change model that's really the basis for my wanting to elicit students' current conceptions, and then present them with data or evidence that they must somehow account for. It's an interesting read, although some of the language and the constructivist bias can be a tad annoying.

And as I stated in the previous post, getting at students' ideas about the origin or origins of species necessarily involves a religious discussion. I jumped right into the discussion today with my 2 regents classes. I asked them to draw a diagram that showed in some way how the earth today came to have over 1.7 million different kinds of living things and to include a timeline. Most students struggled with how to represent their ideas visually. "God did it. How do I draw that?"

I should say that I did model what I meant by a diagram. I had read the word "asteroid" in a student's homework assignment, and elaborated on my own. Here is my model diagram and explanation:

It's a silly idea and a simple diagram, just to illustrate how one might take the idea that all the living things on earth arrived on asteroids from outer space and turn it into a visual representation. I got some interesting stuff, and I would like to post some of the student work, but I will have to get their permission first.

Not surprisingly, many students had a vague notion that god did it, but no understanding, not even a biblical understanding, of how or when that might have happened. A number of students opted not to diagram their religious understanding, which I of course gave them the freedom not to do. They instead diagrammed what they thought the scientific version of events was, and quickly added that they didn't believe it, it's just what scientists think. Needless to say, their diagrams of the scientific view were as sketchy as the religious diagrams.

Tonight's homework was to consider the fossil evidence that some millions of years ago, not one of the species of mammals that live today - giraffes, elephants, whales, humans, etc. - existed. How does your model (diagram) account for this information?

Introducing Evolution by Natural Selection

I'm slowly introducing some concepts to my students about evolution without actually mentioning evolution or natural selection. As I noted in an earlier post, I'm using mealworms as a springboard, of sorts. Today we discussed some differences and similarities between the mealworms we observed in class, and in the end I introduced the term "variation." We also discussed some of the more obvious variations among humans, but in my experience, students generally think of human variation as a special quality of humans - we are, after all, not "animals" in their view. For homework I am having students consider whether all this variation is such a good idea, from the point of view of the mealworms, or mightn't they be better off if they were all identical? I'm looking forward to the discussion in class.

What I am a little apprehensive about is the inevitable discussion of religious accounts of the origin of species. I like whenever possible to tap into students' prior knowledge or existing models of how the world works. But in eliciting prior knowledge about this particular subject, some religious conflict will be unavoidable. The fossil evidence particularly contradicts biblical accounts of creation, and students will have to find a way to deal with that conflict - either by rejecting the evidence (as many religious fundamentalists do) or by modifying their current models.

I will devote the next few posts to discussing how these conversations with students progress over the next couple of weeks.
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The other strand we are currently working on is using the mealworms to conduct controlled experiments. In both my regents classes, students are now reviewing experimental design by working on a simple problem question, testing a hypothesis about different foods and how they might affect the growth of the mealworms. Afterwards, students will continue observing and asking questions, which should eventually lead to more sophisticated and complex experiments. Students will have ample time to collect data over the course of the school year in conducting experiments that will relate in some way to one or more of our major themes in regents biology - living vs. nonliving things, homeostasis, ecology, heredity & genetics, reproduction & development, etc.

Mealworms Redux

I would have thought mealworm investigations were pretty standard in the elementary grades - observation skills, life cycles/metamorphosis, a few controlled experiments varying types of food, etc.

I decided to bring the investigations into my 8th grade Regents Biology classes, simply because I wanted an inexpensive object of long-term observations and a vehicle for discussing things like variation, adaptation, reproduction & development, heredity (to the extent possible within our time constraints), ecology - niches, etc. A lot of content can be related to the mealworms and I can also get students to do controlled experiments that will be part of their required grade 8 project here in NYC.

So far the students are enjoying their investigations. We have completed most of the preliminary observations of the larval stage (the “worm” stage) and are now setting up a couple of simple controlled experiments that will vary the kinds of food they eat, for example, and chart their growth over a couple of weeks. Most of my students, surprisingly, have never done any mealworm investigations. The few that have seen them before did so in the 2nd grade, so they certainly don’t mind revisiting them and looking at them through 8th grade eyes.

I’m not exactly sure how long a complete life cycle will take given our classroom conditions, but they should be able to come up with some more interesting investigations that they will do individually or in pairs to complete their long-term projects – investigations involving other stages of development, for example, transition times, etc.

I’m trying to transition from mental models/black boxes to mealworms and then to Darwin’s model of evolution through natural selection. I'll give more details as I work it out, but the main transitional concept will be variation, as we look at differences among our mealworms in terms of observable features, behaviors, growth patterns, etc.

Mental Model Details & Analysis

I'm wrapping up my black box/mental models activity this weekend - students are completing their lab sheets for homework. Nothing ever goes as expected. Given that fact, I'm happy with the way the activity came across, and I believe it's a nice springboard for the rest of the year, where the question of how scientists work and how they "know" what they know will come up again and again, especially now when we begin our evolution unit and consider Darwin's model. I was pre-viewing PBS's Evolution video, and struck by the similarities between our black box activity and the struggles of scientists in his day to explain the origin of species.

Let me demonstrate a little. Here's one example of a black box I set up:

(There are 3 other arrangements. Again, this is an activity I adapted from FOSS: Models & Designs.) I use a lot of tape, having learned a long time ago that the impulse to cheat is irresistible. There's a little ball inside, and it runs up against these cardboard or foamboard obstacles. Students have to figure out what's inside the box based on the sound and feel of the moving object. I don't tell them anything about what's inside. They usually focus first on the moving object, and the most common inferences were marble or battery. Battery seems an odd guess, but the obstacles make the object move in strange ways, and a cylindrical shape is a plausible explanation with some of the boxes. At some point during our discussions, a student will object to the battery hypothesis and propose that there are other things in the box (obstacles or whatever) that cause the marble to move in funny ways. Students argue and become quite attached to their ideas, holding on in the face of strong evidence against them - this activity mirrors what happens in the "real" scientific community in many ways!

Keep in mind this module from FOSS is geared toward 5-6th graders, and I can't imagine why. My 8th graders have a very low tolerance for intellectual frustration and had difficulty devising any methodology for figuring out what was inside. Some students sat there repeatedly, incessantly shaking the box near their ears, even a few days into the activity, expecting some magical voice, I suppose, to reveal the contents to them. I modeled a few strategies for how to work the box without announcing that I was modeling a strategy - rolling the moving object around the perimeter, noting where there was an obstacle, mapping it on a piece of paper, etc. I should have announced it. Toward the end I thought of another technique, and had students tape an index card directly to the box and start marking where the obstacles were. That was a big help and I wish I had thought of it earlier.

Oh, what is the twist that I added to the original FOSS idea? I used a steel ball instead of a glass marble. At a certain point I alleviated some frustration by asking student to focus on the moving object. Some had suggested a marble. We discussed what a marble was - a glass sphere - and whether it might be something other than glass. Was there any test we could do to determine if it was glass or not? What else might it be made of - wood, rubber, metal - could we do any kind of test that would tell us if it were any of those materials? Someone suggested if it were metal, it would be attracted to a magnet. So out come the magnets. Now we have not only narrowed down the possible materials that the object could be made of, we have a new tool or technology for manipulating the object and creating a map of the inside of the box. A lot of scientific method here, and a little messy like real science can be. Observations, tentative explanations or hypotheses, testing hypotheses, revising the model, arguing, sharing information, inspiration, using technology to refine the model, and so on.

You can download the lab sheet I made with some notes here (MSWord). This is my original lab, without any modifications. I would certainly revise some of it in light of my experiences, but at the moment I'm focusing on the next unit and cannot revise it now. I definitely guided students more than I wanted to, but I had to balance the process of discovery against the frustration level that sometimes threatened to undermine the process anyway. If I have time I will post a student example later this week.

UPDATE

Here's a nice alternative activity from Exloratorium if you can trust your students not to cheat!

Mental Models

I have been spending the first classes this year for my regents students working with the idea of mental models. I discuss the rationale briefly in my course outline. The activity itself is derived from the FOSS Models & Designs curriculum, but I have thrown in an additional twist. I will post a fuller description of the activity itself after my students have finished with it, but basically it's literally a black box with something going on inside that students have to figure out using the sounds it makes and the feeling of it as the thing inside the box (a marble? a battery? a rock? were some of the hypotheses) moves around.

It is a great model of the scientific process, involving observation, reasoning, asking questions, testing, collaboration & communication. So far I think the activity is going over well, despite a good deal of necessary frustration and the usual attempts to circumvent the process (i.e., cheat). I try to look at this in a positive way, acknowledging the importance of curiosity and our need to know, while at the same time comparing it to a video game, in which the fun is all in playing the game, not necessarily getting to the end of the game or "winning"- what fun would a video game be if there were a cheat button where you could immediately destroy all the bad guys and win - game over. In this activity, the contents of the box are trivial and unimportant - it's the process of discovery that matters, how we figure out what's in the black box.

The twist that I've added to the FOSS idea will allow students to use a new "technology" to gain a better understanding of what's going on. I won't reveal the twist until the students have gone through it. I will say, however, that the idea came to me while reviewing the history of the discovery of the atom and it's structure. Thompson's "plum pudding" model (no nucleus) was replaced by Rutherford's (and later Bohr's) nuclear model (electrons "orbiting" a central nucleus). Rutherford came up with the model after experiments in which alpha particles were fired at gold foil - most went straight through the foil, but a few bounced back, a phenomenon incompatible with the idea of an atom with uniform density, and thus the tiny, dense, central nucleus was postulated. Suddenly it occured to me...TBA

The Globe Program

The Globe Program is a NASA-funded global environmental science research project.  Students from around the world collect data about the local atmosphere, climate & weather, soil conditions, water quality, land cover, etc.  Students collect this data according to rigid protocols and standardized equipment and, if their teacher is certified Globe teacher, they can submit their data to an online database that other students, and scientists for that matter, have free access to.
 
They also publish a curriculum that you can follow without any training and use in your classroom, but you will not be able to publish your data.  For many teachers this will not really be an issue.  They have some great activities and you should check them out, especially if you are teaching environmental or earth science.

Living in NYC presents special problems for students and teachers wishing to engage in the program.  Specifically the protocols for studying soil present tremendous difficulties - just finding soil can be a challenge! The parks department is obviously reluctant to allow much digging around and most of the city is covered with buildings, concrete, or asphalt.  I am working with a couple of other people at City College this summer to examine ways that we might implement the soil protocols in NYC. 
 
One of the concerns I have is the relevance issue.  Why is it important in NYC to monitor soil conditions?  Agriculture isn't a great factor, and about the only place where plants grow in abundance is the NYC Parks, which are practically off limits anyway for our purposes.  So we aren't concerned in general about soil quality for crops, the parks are off limits, and we aren't too worried about the topsoil drying up and blowing away - it's already covered anyway with non-living materials! That pretty much leaves monitoring soil for evidence of other environmental factors, such as pollution.
 
Of course, there's also the big picture angle, that students need to be aware of the world outside of their urban environs.  We can study soil locally and make connections to what is happening in areas where agriculture is important and what's happening in forested areas around the world.  What about connections with Regent's Living Environment?  I will probably spend a little time on the soil protocols/activities in looking at ecosystems, the interaction of biotic & abiotic factors, but I doubt that I will have time to do a lot of the activities, given the scope of the living environment curriculum.  On the other hand, I will also be teaching a 7th grade class which includes, in my district's curriculum, both ecology & geology, where the connections with a study of soil are more obvious. 

Summer Work

After swearing that I would not do any summer work this year and instead spend some time with my own children, I again got pulled into doing several school-related projects.

Today I finished the formal but introductory part of a program with Columbia University's GK-12 program, an NSF project that brings together many of the resources of Columbia University with math/science teachers in NYC public schools. Most importantly, perhaps, is the partnership between a Columbia grad student and teachers. In my particular case, I and a colleague from my school will be sharing a grad student from the computer science field. We are discussing ways of bringing his particular expertise into the classroom, thinking about information theory & technology generally and seeing how we might make connections with genetics/evolution, or even ecology. These are just abstract ideas at the moment, and I will discuss them more as we flesh them out and come up with specific activities or lessons.

Of course there's the more concrete benefit of using computer technology in the classroom for more specific content objectives. Part of our training this week involved the use of Vernier Probeware, which we will be able to use in our classrooms next year. Our graduate student (and a team of undergrads if necessary!) will be available to help set up the equipment and run it in our classes. A classic example of the uses of probeware is measuring the changes in CO2 & O2 levels with a plant in a closed container, comparing these levels in light & darkness, relating to photosynthesis & respiration.

Next week I start work on another project, which I will describe in a separate post, but also related to a GK-12 grant at another university. Then, at the end of the month/beginning of August, I will be involved in a summer institute with the NYC Department of Education - not exactly sure yet what that will entail...

Change of Heart?

I had always opposed teaching regents (high school level) science courses in grade 8 in most of our District Six middle schools (Washington Heights, Upper Manhattan, NYC). My reasoning was based on a few observations.

1. Most of our students are deficient in a number of basic science skills and habits of mind, partly from inadequate science instruction in elementary grades, partly from # 2 below.

2. Most of our students have not had any accelerated science instruction in any previous grades.

3. Combining 1 & 2, most of our students have not mastered basic middle school level science concepts & skills by the time they enter grade 8. This is a particular problem because, of course, the regents curriculum assumes that the student has certain requisite background knowledge from middle school science. As an example, in regents bio, students jump right into DNA structure & replication, protein synthesis, & so on. It is assumed that students have already mastered Mendelian genetics - dominant & recessive genes, Punnett squares, pedigree charts, etc. Of course we don't teach that topic until grade 8. So that's an additional topic for my students to deal with in taking regents next year.

4. Most of our middle schools do not have adequate facilities (science rooms with running water, space, lab tables, etc.), nor do they have adequate materials for teaching a rigorous regents class with required laboratory hours. To the extent that it is done well, it demands a lot from the teacher in terms of drumming up materials, labs, activities, etc.

Most schools are unwilling to provide the number of hours per week of science necessary to address the problems outlined above. To be more precise, I’ve been looking at the science programs in a number of high schools. Most of them program 7.5 periods per week for 10th graders to complete the Regents Living Environment course. I found one high school that actually offers a 10 period per week section for students who are struggling academically and at risk of failing the exam in a regular 7 period setting. I’ve seen regents offered here at some of our middle schools at 5, 6, or 7 periods per week. And that’s for 8th graders! Granted, these are usually higher functioning 8th graders, but still, most have not had the benefit of the full range of middle school topics before being thrust into a high school biology class.

So why am I teaching regents biology next year?

1. My school has scheduled 8 periods per week for the regents classes next year. That increases the odds of success.

2. I want to teach the kids I have this year (in grade 7) again next year. In spite of my reservations about looping, there’s something special about “graduating” (it’s a NY thing I suppose – 8th grade graduation isn’t something I am familiar with from NC) with a group of students that you’ve been with for a couple of years.

3. One way or another I plan on teaching regents living environment from now on – that means one way or another I will not be looping anymore. That probably means moving on to another school after next year, probably a high school, where I can settle down and become proficient at teaching biology.

4. I think I can do the job well and I’m willing to invest a considerable amount of time, energy, & effort to make it work – see #3 above.

So really, I haven’t had a change of heart per se. I still think that under current circumstances most students would be better off taking regents in high school. But my students are getting regents next year with or without me, so I will make the best of it, in the interest of my students as well as myself.

No News is News

As this school year winds down, it becomes more & more difficult to get things together for next year. Report cards demand attention, which means final exams need to be prepared, grades need to be computed. At the same time, students are being treated to numerous end-of-year activities, treats, field trips, and the like. Makes it difficult to maintain any semblance of organized instruction. Perhaps a good time to reflect on what went right or wrong with the current year and use that knowledge to prepare for next year.

A look at my preparations for next year betrays an ambitious attempt to be exceedingly organized. This derives from a realization this year that I never got a grip on the curriculum, never was clear about where I was going or how I was going to get there. Actually, I knew conceptually where I wanted to go, and I was clear in my mind about the content and the links from one content piece to another, but I had only a vague idea about the instructional part of it, how to get the students from where they were to where I wanted them to be. I was also over-optimistic about what the kids would be able to do themselves in terms of keeping a notebook, actively engaging in an activity, and so on. I relearned this year, after 3 years out of the classroom, how much our students demand structured instruction. They need tremendous help getting and keeping themselves organized. In order for me to provide that structure, I need to be doubly organized. Hence the planning and fretting about next year.

The Living Environment curriculum helps. It’s a rigorous program (especially for 8th graders). There’s lots of resources, including required labs, practice exams, review books, etc. There’s a good balance of pure content, broad conceptual understandings, process skills, and lab techniques. There’s a pre-determined final exam that will keep me focused, and it provides a great incentive for the kids – if they pass it they will enter 9th grade with one year of high school science and one of 5 required regents exams under their belts.

For next year I want to know ahead of time exactly what a notebook should look like – how it should be organized, how many sections they need, what to put in each section. That basically means I need a notebook of my own that will mirror theirs. I wish I could create a standardized lab report format for their lab notebooks, but so far I haven’t found any that are general enough for the wide variety of labs that we will do. Not all labs, for instance, are controlled experiments. I’ve seen too many lab report format samples force that structure onto labs that aren’t controlled experiments. A lot of labs involve building models or require simple observation of some phenomenon and inference about what’s going on, with little or no data per se, no real “problem question,” very little in the way of controlled variables. And don’t get me started on the misuses of the term hypothesis. So I may give up on the hope of finding a single lab report format and come up with 2-3 different formats and post them around the room for students to use as appropriate to each particular lab.

I also recently learned that I will have some help in the classroom in the form of a Columbia engineering student. He will work with me to plan some activities, about one every week, most likely involving the use of Vernier Probeware, which the Columbia program will provide. That’s exiting news, I’m just hoping we get some Co2 or Oxygen probes to do some photosynthesis/respiration labs. That would be way cool. I'm so looking forward to next year.

Student Voice Over

I have one example of a student voice over posted in the comment section of this post:

Test Question 2

I'm not happy with the restrictions on comments in my blogger account, which don't allow a commenter to post a target="_blank" tag, which would allow the animation and the voice over to pop up in their own respective windows, so now viewing the animation and voice over takes too many steps. I'm looking into using haloscan as an alternative comments handler.

For the sake of convenience, I'm posting the animation voice over here complete with pop-up windows:

Transpiration Animation

Voice Over

Living Environment Course Outline

Here's the planned sequence of my living environment course:

Unit 1: Introduction to Mental Models, Scientific Method & Living Environment

Unit 2: Evolution: Darwin's Model

Unit 3: Principles of Reproduction & Heredity – Mendel's Model

Unit 4: Cell Biology & Homeostasis

Unit 5: Modern Synthesis & Evolution of Life on Earth

Unit 6: Ecology

Unit 7: The Future & Human Impact on the Environment

Unit 8: Human Biology & Homeostasis

Rationale:

I would like to begin the year with a unit on evolution, since I truly believe the Dobzhansky quote about biology only making sense in the light of evolution. At the same time, I know that my students do not yet have the requisite background information to appreciate how evolution happens - heredity, genes, DNA, mutations, etc. I thought about the least number of steps I would need in order to get to evolution. I decided to break up the evolution unit and do a "simple," natural selection unit before heredity & cell biology. That will require revisiting modern synthesis after cell biology. On paper this makes sense, I'm just not sure my students will be able to handle the back-and-forth nature of such an approach. 

Of course Darwin formulated his theory of natural selection knowing nothing about genetics or simple Mendelian rules of heredity. Mendel, for his part, knew nothing about the actual mechanism for passing on traits - no idea what a "gene" was. He used the term "factors," a rather vague term for some unknown entity that was responsible for carrying traits. So why then must students know what genes are before studying heredity? Why must they understand heredity before they study evolution? I suspect that time is the issue. It simply takes longer to "cover the material" if we start with observable patterns and phenomena, then work toward the unobservable mechanisms. It seems easier to work from the mechanism, since the mechanism explains the phenomenon and is ultimately necessary to understand the phenomenon. But this is the reverse of how science usually works, and leaves the teacher open to the constant whining of "Why do we need to know this?" I want to start with the big questions - How did we get here? What makes us "us?" How do our bodies work? These are questions that students are genuinely interested in, and the answers to those questions require dabbling in some areas of study that are not otherwise immediately "interesting."

So, start with big ideas that arouse curiosity, then move to the details that are necessary to understand the big ideas, revisit big ideas. That's my approach to the extent possible. Learning is and teaching should be an iterative process.

The other difficult decision was whether to finish the year with ecology or human biology. Both are heavily tested on the exam, and both offer great opportunities to revisit major themes of the course. I decided that ending with human biology would be the most enjoyable for my students.

Planning the Course

My school uses a "looping" strategy for teacher rotation. What that means is that teachers follow their students from grade to grade: from grade 6 through grade 8 and back to grade 6 again.

This is a marvelous idea in theory and in practice has many benefits. Teacher get to know students much better, children feel more secure in having familiar faces in front of them every September, parents have fewer teachers to get to know and stay in contact with, just to name a few pluses.

On the other hand, (you knew that was coming) the policy is murderously difficult for science teachers. Planning and executing science instruction is unlike planning and execution of any other subject area. In New York State, the content is rigorous and unrelenting (a mile wide AND a mile deep if you read through the core curriculum objectives!). Science instruction demands not only a deep understanding of the content, but quite a bit of materials gathering before class, materials management in the classroom, and materials clean-up after class. No othe subject area teacher is faced with such a burden of planning, materials management, and cleaning-up.

Extensive planning goes down a lot more easily if you know that it will make your life simpler next year - you can build on and improve existing plans rather than starting from scratch. The logistical workload decreases and you can concentrate on doing a better strategic job in the classroom, polishing your presentation, anticipating student difficulties, etc.

With looping, that strategy breaks down and every year is like starting over. It's nearly impossible to store plans and materials from this year, not to be used again for 3 years.

I have spent most of this Memorial Day weekend planning for next year. It takes a tremendous amount of effort to plan a new course. I am enthusiastic about it, however, as I fully expect to be teaching Regents Living Environment for some time to come. I will be updating my website with new resources as they become available. My major accomplishment this weekend was to develop a vocabulary database for the living environment curriculum (with thanks to Bill Siebert via Mr. Comet). I am also creating a list of links to other science teachers who are teaching Regents Living Environment. Stay tuned.

Posting audio files

I had hoped to let students post audio files of their voice overs - looks like I will have to do a little extra work to get that to happen. I forgot that they cannot upload a file from the comments form. So, either I make a separate post for each voice over, or I upload the audio files to my website and place hyperlinks to the uploaded files in the comments section (which is what "upload" does anyway). At any rate, I have uploaded my own voice over - I wanted to play around with the recording aspect, and see how hard it would be to actually do a voice over. Not professional quality audio, and I'm not giving up my day job, but here's how to synchronize the voice over & the animation.

Both of the links below are designed to open up new, separate browser windows. Open the animation window first by clicking the link below:

Transpiration Animation

Then open the audio file below. Change the size of the windows so that both the animation and your audio player can be accessed at the same time. I've allowed a second or so at the beginning of the audio file, so press the play button for the audio, then the play button for the animation.

transpiration.wav

You may have to let both files run their course first, then synchronize. For some reason the files run automatically when open and I've not found a simple way to stop them before they are finished.

My timing on this recording isn't perfect, and with a slight adjustment I could make it better, but it's only here for illustrative purposes, so I'll leave it as is. When student recordings are ready, I'll post a link to them.