Dog Days

After stepping in dog crap yesterday during my evening jog across the George Washington Bridge*, I thought this an apt title for how I'm feeling right now about regents biology in grade 8.

I'm playing content catch-up. Rushing through body systems with the dreaded lecture-textbook-quiz drill that I so despise, but seeing little alternative at this late stage of the game. I will definitely need to work on pace & sequence and all that next year.

If you have to lecture...

I'm using a lot of power-point presentations, which I find infinitely preferable to writing on the chalkboard and having students flip through the book for pictures. For some reason, students seem more engaged - most likely because I don't have to divert my attention from the class while writing on the board, so I can monitor them almost constantly. More importantly, the pictures often precede the text, so I can engage them with the pictures, ask them to make predictions or recall information based on prior knowledge, and introduce the text as we go along - again, without turning my back or giving them the excuse that they are waiting for me to get out of the way so they can write the notes (with all the opportunity there to lose focus). Ms. Frizzle had a post recently defending the use of powerpoint presentations - I didn't know there was even a controversy. I prefer not to lecture, but if one must, then powerpoint is the way to go with this age group.

What about the time it takes to prepare a powerpoint presentation? I cheat. A lot of powerpoints can be found on the web, and I just edit them for my own purposes. For that reason, I won't be posting my presentations, at least for now. But I do use a lot from Mr. Kolakowski's website - he's a regents LE teacher in upstate NY.

On the other side, we are still working on exit projects, for which I give them our Monday double periods. I will post separately on this subject later. I also have to get the remaining required state labs in, but I'm in no rush on that. I will post my thoughts on those labs as we do them.

*I was transitioning from bright sunlight to dark shadows and couldn't see the stuff, even looking back after I realized what that squishy feeling was under my left foot. I'm always hyper-vigilant about dog crap in this stinking neighborhood and it still found my foot. Do I sound a little (pet-) peeved? I am.

NYC DOE - Grow UP!

I just googled "excretory system" at school on the Department of Education server, and got this familiar message:

Access Denied

The requested document, http://www.google.com/search?hl=en&q=excretory system&btnG=Google Search, will not be shown.

Reason: DDR score = 139. This page will not be displayed because it contains prohibited words or it has exceeded its tolerance of questionable words.

I've seen this a lot when trying to navigate to a particular site or page of a site - a lot of legitimate science content is off limits using the DOE filters - , but this is a first. I can't wait to get home and see what google returned about the excretory system that is so offensive they can't even show the search results!

Later that day...

So here are the results of my search:

Excretory System
... Excretory System Functions Invertebrate Excretory Organs Vertebrates ...
The Human Excretory System Kidney Function Hormone Control of Water and ...
www.emc.maricopa.edu/faculty/ farabee/BIOBK/BioBookEXCRET.html - 24k - Cached - Similar pages

Pathfinders for Kids: The Excretory System - The Garbage Collector
This pathfinder is a guide to help kids find information about the excretory system.
infozone.imcpl.org/kids_kidny.htm - 11k - Cached - Similar pages

Excretion
... You would probably figure out a system of searching and removing. That would
be an excretory system. Your body does the same thing every day. ...
sln.fi.edu/biosci/systems/excretion.html - 8k - Cached - Similar pages

Human Excretory System
... Its numerous functions make it "part" of the circulatory, digestive, and
excretory systems. ... There you have it, the Human Excretory System. ...
www.borg.com/~lubehawk/hexcrsys.htm - 53k - Cached - Similar pages

Excretory System
... Some diseases and disorders of the excretory system include:. Nephritis is an
inflammation of the glomeruli, due to a number of possible causes, ...
biology.clc.uc.edu/courses/bio105/kidney.htm - 26k - Cached - Similar pages

Excretory System
EXCRETORY SYSTEM. OVERVIEW :. On this page you will learn about the Excretory
System, which removes the unwanted materials from our body. ...
library.thinkquest.org/ 10348/find/content/excretory.html - 6k - Cached - Similar pages

Excretory System
The job of the excretory system is to remove various produced by the body.
The removal is known as excreation. It is important for the body to remove these ...
www.stclement.pvt.k12.il.us/ StudentWeb/science/excretionc/excsyst.htm - 2k - Cached - Similar pages

Excretory System
Chapter 42 - Excretory System. Function of the Excretory System. The excretory
system functions in ridding the body of nitrogenous (nitrogen-containing, ...
faculty.clintoncc.suny.edu/.../files/Bio%20102/ Bio%20102%20lectures/Excretory%20System/excretor.htm - 21k - Cached - Similar pages

Excretory System
... Endocrine System Circulatory System Lymphatic and Immune System Digestive
System Excretory System Muscle and Skeletal System Respiratory and Skin System ...
www.scientia.org/cadonline/Biology/excretory/home.ASP - 3k - Cached - Similar pages

The Excretory System
... Nitrogen Wastes ..The Human Excretory System ..Water and Salt Balance . ...
Excretory System Functions ..Hormone Control of Water and Salt . ...
www.cartage.org.lb/en/themes/Sciences/LifeScience/ GeneralBiology/Physiology/ExcretorySystem/mainpage.htm - 5k - Cached - Similar pages

OK? So where are the questionable or objectionable words? The only questionable word I see is the misspelling of excretion - excreation in the 7th entry.

I realize there are ways around the word "excretion" and had no trouble with "kidneys" for example, but really, the DOE security settings are a joke.

And don't even get me started on the restriction on accessing the sports websites or even an article on sports from the NY Times. Some of the girls in my class sit around (before or after school starts) drooling over the Gotti boys and the DOE security system has no problem with that. But let someone try to read a sports page and whoa, hold on there, sorry, DOE don't allow sports over our internet servers!. I can't think of any legitimate use of celebrity gossip crap, but there's no restriction on it. I can think of plenty of uses for sports - statistics, secondary research, social studies connections, etc., but kids can't access any sports info on the DOE servers. Gimme a break.

Exit Projects in Full Swing

The dilemma, of course, is that my primary focus this year is getting my students to pass the regents exam, and as I've stated ad nauseam before, I'm a little nervous about it, having no prior experience in teaching the curriculum and little or no support from the state of New York (as in the New York State Regents Living Environment Exam).(1) On the other hand, grade 8 students are supposed to also complete an 'exit project" which I have likewise discussed in earlier posts. To guide students properly through a year-long exit project is just a bit more than I can handle, so we are doing pared down projects that are really just getting started and are due on May 6th, at least as far as the students are concerned. In reality, I want all their research and data collection completed by May 6th, and if we take a little longer to get everything written up properly and presented, then maybe closer to May 20th for the final due date.

Most students are doing fairly simple projects - a good number of the old stand-by germination experiments, plant growth experiments, etc. Some students are taking my advice and reworking some of the experiments we already did in class (gelatin-detergent lab, e.g.), others are sticking with their secondary research projects on genetic diseases. What I expect from my regents classes is a solid experimental design, an extensive set of data, and a thorough understanding of the biology concepts to explain the data. I am giving them Mondays during class to work on projects as we continue with some pretty old-school lessons on human biology the rest of the week. Any other time they need will have to be after school. I will be collecting their experimental design diagrams later this week and post some specific examples, discussing how my expectations are different from what I've seen in similar other projects. Such as:

One group is investigating how salt affects plant growth. A pretty standard middle school science fair project, not very imaginative, not that exciting. Mostly this is done with a control group, a group that gets maybe a 5% salt solution, and a third group that gets a 10% salt solution, e.g. The 10% usually dies or doesn't grow at all, the 5% maybe lives but looks pretty sickly, and the control group does just fine. End of experiment. At this level, however, that would be a starting point. Now the challenge will be to go back and re-do the experiment with concentrations of salt between 0 - 5%, challenge them to find ANY concentration of salt that does not negatively affect plant growth. There are of course other directions the investigation could lead, such as looking for plants that are more resistant to salt, for example, but under the circumstances we will stay with the salt concentrations. Students will then have to discuss the physiological effect of salt on the plants. Why does salt harm the plants, maybe describe the role of salt in our own bodies, etc. You get the idea.

(1)References to curriculum matters here and here.

UPDATE

I neglected to mention that a sizeable chunk of the regents exams is related to understanding experimental design and the scientific process, so I realize that having students work on these projects is not taking away time that we need to prepare for the exam, it IS preparing for an important part of the exam. I am still struggling on the whole with how to integrate content & process over the long haul - I can do it in short bursts of activity, but putting it all together for a coherent year-long sequence of instruction is not easy.

Dissection

Sheep Hearts. Our first real dissection of the year. We have boxes of these things in the supply room, left over from the Insights Human Body Systems kits that are supposed to be used in grade 6. For whatever reason, the sheep hearts lie there unused, many teachers will either do a dissection as a demo, or avoid it alltogether, so we have a surplus.

I didn't take any pictures but there are a few on the internet that I will link here in case you wind up here:

Sheep Heart - Labeled

I used a simple checklist for students to document their work and they had to sketch their observations as well. I got the worksheet off the web, but I've lost the link - I'll search for it later and post as an update.

The kids love this stuff, for the most part, but I wish the dissections could be richer. I would like for them to be able to measure something, make comparisons, but I could neither find nor think of any angle.

Update

I accidentally hit the publish button before I was finished, it being now a Saturday night and I'm composing this post during time-outs in the Final Four games.

I'm thinking of some possible measurements for the frog dissections that we wll do in a couple of weeks. I'll post more as I work out the details.

Back to Basics?

After going through a series of labs and projects over the last few weeks, I looked at the calendar and the curriculum and started to panic. Actually, the panic began when we spent 2 weeks on a digestive system project and got disappointing results on the regents test items relating to digestion. Now I am looking at a good deal of content that still needs to be covered, wondering how I can fit it all in. I've got most of the human bio topics still to address, plus ecology. I need to revisit evolution and genetics in the ecology unit and genetic engineering in the human bio section. That's about one calendar month for each of those major sections, then a couple weeks for regents review in June. That means any labs or projects we do need to be pretty tightly connected to the curriculum, limited in focus, and held to a pretty tight schedule. Looks like a lot of planning & thinking this weekend about how to do this without lecturing full-time for the next 2 months. At the moment my head is empty of ideas. I do have a bunch of sheep hearts lying around at school that we can dissect, so that's my fall-back lab for next week. Just need to find some interesting angle on it...

Results - Of Sorts

(Original Post on this Topic)

Good Technique:

This group did a nice job of keeping the detergents within their respective wells. The row of 3 smaller wells with virtually no change were for plain water (control, center well), Woolite (top of picture between 2 & 6), and ALL (lower portion of picture between 3 & 5). There are no enzymes in either of those two detergents.

Bad Technique

This group was either careless with the drops or jostled the petri dish around after drops were in place. The enzyme action is all over the place, and no useful data can be gathered.

However, of the 15 pairs in my class, we had about 12 with good results, and consistently Tide & Cheer worked best on the gelatin. Don't know if that translates into better cleaning action on real stains with real clothing, but I will encourage the student from yesterday to pursue that angle of investigation.

Science is a messy business

A fellow on a biology listserv just blasted cooperative learning and declared, without hesitation, that kids learn best when a teacher stands in front of the room and explains things to them. I hope we one day get past this "one true way to teach" false choice that so many educators are hung up on.

I wonder what his labs are like? I ask, because I have done a series of lab activities lately that were quite messy. Their original purpose was content based - I had a specific content objective that the lab was supposed to demonstrate. In each case, however, I have wound up teaching more about the scientific process than the content, because if I am honest with my students (which I ALWAYS am :>) and help them analyse the results and draw valid conclusions, then all the labs have been inconclusive - they do not conclusively demonstrate the content objective I started with.

Now, I think this is OK, or even pretty cool really. Students learn how difficult it is to control all the many variables that might influence the outcome of an investigation. They learn about the limitations of our measuring tools, about the importance of following a procedure precisely and consistently, the importance of repeated trials or large samples, or carefully recording results and calculating averages, e.g. They even get ideas for exit projects - either re-do one of the experiments and try to clean up some of the mess, or they think of other possible questions to investigate.

A concrete example. I found this series of activities on enzyme action. I am only using the one activity (Mello Jello) to test the effect of different detergents on dissolving the proteins in Jello - some of the detergents have enzymes, some don't:

The jello is prepared and poured into petri dishes, after adjusting the pH with sodium carbonate. Students use a straw to poke wells into the jello, then place a few drops of detergent solution into each of the wells. Tomorrow they will measure the change in the diameter of the wells after extracting the liquified jello with a pipette, presumably the ones with greater enzyme action will dissolve more of the gelatin. I've left out a lot of details, but it's a pretty nice set up, if it works. Of course the set up isn't that easy for 8th grade students. Some of them still have motor skill issues.

I didn't make it any easier for them. I made the gelatin a little too soft, so extracting the plug from the wells was a little difficult. Students had difficulty placing the drops in the wells with the detergent, spilling drops all over the place, probably contaminating some of the wells.

At the end of the period a student asked if she might be able to actually test detergents on clothing as an exit project. She made that connection herself, I didn't suggest it. I think it's a great idea if she pays close attention to the role of enzymes in the process and investigates the variables that affect the enzyme action, the organic molecules that the enzymes work best on, etc. I have seen this activity done poorly, where the only point was to do a product test and little or no science content was developed from it. But investigating enzyme specificity, pH, temperature, etc. seems like a valuable enterprise to me.

I have no idea what results we will get tomorrow. If the results are inconclusive, that's OK. Students will have learned some lessons about the scientific process and they are at least thinking about enzymes, meaning that they might actually be curious enough to pay attention when I have to "explain" it to them.

(Follow up post)

Disappointment

I went through the old regents exams and pulled out as many questions as I could about the digestive system for a test. There weren't that many that dealt exclusively with the digestive system - I could only find 8 questions out of 9 previous exams that I could use. There were a few of other questions that included the digestive system, but they were concerned with how the digestive system interacts with other body systems, so I couldn't use them for this particular test. I supplemented with a couple of questions from their textbook.

I was not pleased with the results. About 2/3 of students failed the test. I'm not sure where I went wrong. I think I asked the right kinds of questions for the research part of their projects, I had students perform presentations for the class on the digestive system, and in the end I went over all the details in a lecture/discussion format just to fill in any holes in their research and answer any lingering questions. I think I covered pretty well the content that was on the exam, without "teaching to the exam" so to speak. I did not teach with the actual exam questions in mind (i.e., give them practice questions that are paraphrased versions of the test questions), but I taught what the students would need to know in order to figure out the questions.

I could and probably will assign part of the blame to the students. They are simply not working as hard as they should be: Often they go through the motions, complete the assignment, but are not always fully engaged in the thinking part of the game. I have to say that on some level it bothers me that an "accelerated" class doesn't take more pride in their work or go beyond the minimum requirements of a task.

So now what do I do given these circumstances? If students aren't working hard enough, it is of course my job to bring them around. I may have to do what I've been loathe to do until now - start calling parents, sending home tests to be signed, all that nonsense that just reinforces the forced learning mentality - learn or else! But maybe that's just the nature of middle school students, even "high" achieving ones.

Digestive System Model: Photo

A rough idea of what the models looked like - balloons and construction paper. One of the students made the labels as an extra part of the model for hanging in the classroom - it's a nice touch and I wish I could incorporate it into the assignment, but with space being limited, and my room totally overused, it just isn't practical to have 16 models of digestive systems hanging around for other kids to come in my room and knock down.

From mouth to anus is about 25 feet, this model being roughly actual size.

Click here for previous post on this topic.

Guinea Pigs

Fridays are bad days to plan things like presentations, labs, new material, etc., and today was true to form. About a third of my class was out for some kind of musical performance and of course they weren't all from the same group, so several groups had missing members. I also left my camera at home, so no photos till Monday.

Actually a good thing it turns out. In spite of the missing persons, I decided to go ahead with a volunteer group for one presentation. I wanted to use them as guinea pigs, and told them as much when they volunteered, and gave them extra credit for going first - it's only fair since they will make a lot of mistakes that others will learn from (hopefully). And mistakes they did make. They were nervous, which reinforced the need to be prepared and have notes - it's hard to talk off the top of your head when your nervous. A few members of the group didn't know their stuff, so it gave me a chance to ask questions to let the others know what they would be expected to know. They also found out that there's a difference between being able to answer a teacher's questions about a topic and being able to explain something without prompts from the teacher. They didn't speak clearly or loudly enough. Some of them had poor body language, staring downward, fidgeting, etc. Some of the students seem to have learned more about teaching from sitcoms than from observing actual teachers: I don't think I've ever heard a real teacher say, "Now class, today we are going to learn about the digestive system..." - you have to imagine the kid putting on his mock friendly teacher face and reciting that line.

The other students rated the whole group' presentation based on the rubric. I rated individual students. In general they were a bit more generous than I was, which is OK. I will give a final score based on an average of the individual scores and the group scores.

The scale models aren't quite living up to my expectations. They all look pretty much the same: Once they saw a group using balloons for some of the parts, everyone wanted balloons. Making it a group project in class was part of the problem. In the future I would probably make it a homework assignment - they might get a little more creative if they have to look around the house for materials or go to the dollar store or grocery store and find something to work with. Class time was probably better spent preparing the presentations, working together on the research.

Final Parts of Digestive System Project

The basic strategy and introductory components of the project are in this post:

Is eating a "waste" of time?

I've elaborated on the details of the nutrient digestion, as well as a rough guide to the sizes of the various parts of the system to be used for the scale models. The whole project write-up can be found here:

A Journey Into the Digestive System & Beyond

and a set of guidelines and rubric for the presentations.

Guidelines & Rubric

The rubric is an adapted version of a generic presentation rubric from:

Teach-nology

Tomorrow are the presentations. I will post a picture or two and report on their performances.

Is Eating a "Waste" of Time?

I did a little project a couple of years ago on student misconceptions and the conceptual change model. I chose to do my lesson plan on digestion, specifically the fate of the food we eat. In my preliminary research, I found that many students have this idea that the food is eaten, goes through the digestive system, and emerges as waste from the anus (giggles all around). When asked about how much of the original food leaves the body, the numbers were extremely high - 50%, 90%, even 100%. This is quite understandable given our personal experience with said waste and no way of explaining the volume of it produced. Students have this abstract idea that food is needed for energy, but for all they know we somehow extract the energy (whatever that is) from food in the digestive system itself and then eliminate the food when we're finished "using it." Few students seemed to have any conception of how the food is used for growth, maintenance, repair of our own tissues/cells or what energy is. There are a lot of lessons suggested by these misconceptions, but at the time I was taking this class I was required to produce a single lesson plan that would address the misconception. I don't think it was very effective.

For my regents classes I wanted to start with the misconception, so the title of this post was my AIM. As a DO NOW I asked students to describe the fate of food from start to finish, expecting the misconception again to come out in their responses. They were however a little too saavy and mostly mentioned the part about breaking down food into smaller particles that were absorbed into the bloodstream and carried to the cells.

From the misconception, I planned a short project for students to do some cooperative group work, researching the structure and function of various parts of the disgestive system, jigsawing with other experts, then re-convening to put it all together into a coherent narrative. As part of the project, students will construct a scale model of the digestive system - schematically conceived - and use the model as a prop when they present. Each person in the group is responsible for detailing the fate of one nutrient - carbohydrate, protein, lipid. Here are the details:

A JOURNEY INTO THE DIGESTIVE SYSTEM & BEYOND

Your Task

1. Describe the fate of one nutrient in the human body:


a. A protein


b. A fat/lipid


c. A carbohydrate – starch


d. A carbohydrate – sugar.


e. A carbohydrate – fiber

2. Describe what happens if something goes wrong in the digestive system

--Describe real conditions that affect humans.

3. Create a scale model of the digestive system using everyday materials such as
cardboard, fabric, paper, etc.

Procedure:

1. Form groups of 4.

2. Each group member will become an expert in one of the following parts:


a. Mouth & Esophagus


b. Stomach


c. Small Intestine


d. Large Intestine & Accessory Organs (Liver, Pancreas)

3. Jigsaw: At different times, experts for each part of the system will get together to share notes. Then you will return to your main group. Since the different parts of the system work together, you will need to understand how all the parts work together. (See details)

4. Create a storyline detailing what happens to your nutrient. (See details)

5. Create a scale model of the digestive system. (See details)

Presentation:

Each group will have a 5-minute presentation. You will use the scale model as a prop to help you tell the story of your nutrient. (See rubric).

I will post some more of the details as we progress. Here are the original questions I've asked students to research:

Part 1: Basic Research (Use extra paper if needed)

• What does digestion mean?
• What is the basic structure and function of your organ/organs.
• What is the organ made of (what kinds of cells, tissues, etc)? What does the organ do?
• What do the specialized parts of the organ do?
• What does the food look like before it is worked on by your organ? After?
• What kinds of nutrients are digested by your organ/organs?
• What is the sequence of events within the whole digestive system? (Numbered list.)
• What happens if some part of your organ/organs malfunction? Explain, name a disorder.
  
  

Creating Models as Inquiry Process

It's been a terrily busy week with class & parent teacher conferences and the like.

OK, so I presented the DNA modeling activity in my curriculum & instruction class Monday night. I'm still not clear in my mind to what extent the activity is an inquiry activity. I got some good suggestions (below) on how to make it more of an inquiry activity, but as it was carried out I remain skeptical.

First, what is inquiry? One of my problems with this term is that it means so many different things to so many people. In order to answer address the question, "Is it inquiry?" you first have to define the term.

I like the inquiry framework on the TIEE website that shows inquiry as a sort of continuum with totally directed instruction at one end and open ended inquiry at the other. I suppose one could argue for this type of modeling activity to fit within their "guided inquiry" definition based on the level of student ownership - in this case, that was basically in the analysis & presentation column. Everything else was pretty much given - the question, the method, & the "data collection," which didn't really apply in this activity. In the future I would take some suggestions from my classmates and allow students more freedom in devising a model of their own. I would have the following conditions, the students would decide how to meet those conditions:

1. Must be a model made up of repeating parts, just like real DNA. In other words, must be made by linking together 2 separate strands, each strand made of distinct phosphate groups, sugars, bases. May be organized into nucleotide groupings, but...

2. Must be able to replicate by "unzipping" and then adding nucleotides.

3. Must have a color code for the base pairs.

4. Must have the basic shape of a segment of DNA - "ladder" - not necessarily helical - for this activity.

I might refine the criteria a little more before I have to teach this again next year.

A final note. The definitions of inquiry on the TIEE site and others often seem to be limited to studies that require the gathering of data to answer a research question. However, making models is clearly a part of what scientists do (even if it's just a preliminary step toward formulating research questions & hypotheses) and the NY State intermediate level standards include making models:

Interconnectedness

Key Idea 2:

Models are simplified representations of objects, structures, or systems used in analysis, explanation, interpretation, or design.

2.1 Select an appropriate model to begin the search for answers or solutions to a question or problem.

2.2 Use models to study processes that cannot be studied directly (e.g., when the real process is too slow, too fast, or too dangerous for direct observation).

2.3 Demonstrate the effectiveness of different models to represent the same thing and
the same model to represent different things.

Again, not to be pedantic, but these standards for modeling are not included in the "inquiry" standards but the "interconnectedness" standards. It seems to me if the word "inquiry" is to have any meaning, then it cannot be so broad as to lose all it's original meaning related to "inquiring" or asking questions. My bottom line feeling, and I'll stop here, is that in the usual educational all-or-nothing approach to teaching strategies, a lot of useful and important science teaching practices were being cast aside because they weren't "inquiry." Now the desire to include those useful strategies has resulted in a broadening of the term inquiry to include those strategies. The way I see it, building models may be part of an inquiry activity if the model is used to generate questions & hypotheses that CAN be investigated, but the model-building itself only fits within a rather loose definition of inquiry.

(It's getting late & I'm talking off the top of my head. Maybe I'll continue this train of thought & put more research into it for my final paper.)

Expenses Update

In a previous post I discussed some of the extra costs of teaching and vowed to keep a running log. I'm having trouble keeping up with some of the nickel & dime stuff, so I'll just have to estimate. By nickel & dime, I mean the occasional candy or (more rarely) soda that I buy for my helpers and sometimes grocery store/$.99 store lab materials like seeds, cups, pasta, etc. I do have a few larger expenses to add to the total:

Previous total: $347.00 (I'm also rounding off from now on)

Pizza partys for both regents classes: $150.00 (including sodas, delivery tip, etc.)

Computer cable for scanner: 10.00

Stenographer pads for use as Exit Project Journals x 60 = $55.00

2 cases Staples multipurpose paper: $38.00 (sale price)
Nickel & dime since September: 100.00

Total: $700.00

Part A Lab Report: DNA Structure

For future reference - click on the picture which links to the related post.

And here's a student lab sheet. This is the one where I asked the students to compare the model to reality. Interestingly, today we viewed a portion of the PBS/NOVA video: Cracking the Code of Life. The scientist in the opening scenes doesn't do such a good job of describing how DNA is different from the 3D model being displayed by the program's host. (Don't ask me for names, it's been a long week!)

UPDATE: The scientist is Eric Lander, Director of the MIT Center for Genome Research, and the correspondent is Robert Krulwich, whom you may remember as an ABC Nightline correspondent. Lander does note that the model looks like DNA in a "cartoon" sort of way, but doesn't elaborate.

!

The kids still have a hard time with the concept of scale. The student here is trying to express an idea we discussed in class, but she doesn't completely understand it yet. Namely, in one sense our model is much bigger than real DNA, in an obvious sense. In another sense, it is much smaller - we have only 5 base pairs in our model, where a single strand of DNA contains 10's of millions of base pairs. If our model had that many base pairs (using pasta & pipe cleaners) it would be over 1000 miles long! We actually did the math on this in class. Some of the students totally misinterpreted this number - "Wow, you mean we have 1000 miles of DNA in one cell" Well, no, if we enlarged a strand of DNA to the size of our model, it would be 1000 miles long...etc. Actually the fact that the DNA in one cell laid end to end would equal about 2 meters is pretty mind boggling in itself. Just multiply that 2 meters by the 50 trillion or so cells in our bodies, and that's a pretty significant distance also! (100 trillion meters = 100,000,000,000 Km = 62,000,000,000 miles roughly).

I probably went overboard with some of the DNA material, but it's hard to gauge how far to take it. The last exam (January 2005) is pretty heavy on the genetics material, I plan on using the questions for their unit test tomorrow. We'll see how they do.

UPDATE

Pasta DNA Models

I can't remember where I got this idea from, but I needed some easy & cheap way for students to be able to create a concrete model of DNA. Pictures in a book just don't do it. So we created these models with pipe cleaners & pasta.

Students used penne for the phosphate group, fiori make the sugar, pipe cleaners of different color make the base pairs. String binds the pieces together. We used the models to visualize the structure, and to simulate replication. Below is a sample of a lab sheet produced by a student. I did not choose the absolute best example - it has some deficiencies, but it's pretty good.

Updated:

I also asked (as I always do) students to consider how the model is accurate and how the model "fails" (I left that part off the lab sheet).
I actually included the question on comparing model to reality in part A, which I will scan later today. This scan shows part B, in which we replicated our pasta DNA. The drawings are simplified, I did not want them spending time drawing pasta shapes where the emphasis was on the process rather than the structure.

(Click on picture for larger view)

I will discuss the concerns I have about teaching molecular genetics in a subsequent post. I have a lot of concerns about how to teach the subject using an inquiry approach, although one could argue that making models fits within an inquiry approach - I'm just not sure that the model making itself suffices...

Update/Note: Flatbed scanners are a great way to get quick easy images of relatively small, relatively flat objects and the lighting is pretty good. The pasta DNA model above is the product of a scan, not a digital camera.

UPDATE - Revised lab sheets

Lost That Rhythm

Just when I was getting into a blogging rhythm, along came the end of the marking period grades, the beginning of the new semester where I am taking a course again, and now getting up early to go in and mark 8th grade science performance exams before school everyday for the next 2 weeks. Not surprisingly, with all the stress, I've caught a cold to slow me down when I need to speed up.

On the positive side, I just bought a laptop last week and I'm already wondering how I ever got along without it:

Dell Inspiron 600M

Pentium M 725 - 1.6 GHz, 14.1" screen

512M Ram

Intel PRO/Wireless 2915 Internal Wireless (802.11a/b/g54Mbps)

2 yrs tech support

etc....

$1,070.68 including tax & shipping

Nice, reasonably lightweight, reasonably fast - at least as fast as my (admittedly old) desktop at home. The internal wireless card is really nice, reception at home is much better than what I am getting from the older USB based stuff on my desktops. I have wireless access at my school and can hook the laptop to a projector and show animations and other useful web resources to the whole class.

I had been fishing around since early December, watching the prices go up & down, thinking a few times that I let the lowest price pass me by, but this price with 2 yrs tech support was the lowest I had seen for a while, so I took the bait. I checked everyday with gotapex - they post coupons and deals that are hard to find or non-existent on the Dell site itself. This particular deal was $500 off a $1499 or more Inspiron. I think the deal is still on.

I also purchased grading software (ThinkWave), after realizing this marking period that I can't possibly give grades based on weighted assignments by plugging numbers into a calculator - just too labor intensive. So I'm essentially tossing out the old paper & pencil binder with lesson plans, grades, attendance, and going high tech from now on. It may take a while to get the efficiency thing down, but what I was doing before just wasn't working for me.

January 2005 Regents

Hello, Annie Chien here. Guest Blogger, fellow science teacher. So my kids took the January 2005 exam - its part of SOF's effort to stick to authentic assessment. Let me explain...

SOF is a Coalition School (http://www.essentialschools.org/) that focuses on small classes, inquiry based learning/teacher as coach, less is more... While the school sees testing as ONE method of assessing for understanding, it believes that its not the ONLY way. So, for the Regents exams, we designed our curriculum so that the kids have enough knowledge to pass it in January so that they can focus on their research projects in June. This is easy since I see the same set of kids for two years in a row for 9th and 10th grade science (this design used to be called "housing").

SOF use to have a waiver for the Regents exams, but the State mandate took that away. The class of 2007 (who were my students and also the first set of students at SOF to take the Living Environments) had a 92% passing rate. This January, my students received a 97% passing rate (out of 100 students). Several thoughts came in mind. I think in bullets. So, here are my thoughts:

• The 97% is based on the curved score. The passing raw score was a 39 out of 85 possible points.
• Can they cheapen science education any futher?
• Yeah, so I read the exam. It was definitely tougher than most of the other exams. But, hey, I think I taught them enough material for them to all pass it without a curve. I think that the kids were mostly frustrated with the length of the exam. But hey, they really just needed to read each question carefully, then take a couple of extra steps to answer the questions.
• Okay, so it IS a curve and I'm sure their sampling methods were fine. So yeah, if you want to be optimistic, its a good passing rate compared with "others".

So what am I really saying here? I'm happy that my kids passed, but I also feel as though everyone got a free ride, even after all that practice we did, "Yeah, we'll scare you with all the Regents requirement hype, and make the curriculum rigorous like heck, but at the end, we'll just assess everyone on a curve, okay?"

Look, I'm proud of the science curriculum we've set at SOF, and okay, so we are so good at what we do that yes, we deserve such a high passing rate. I just wish I worked in a state where the curriculum and assessment made SENSE.

The exam gave me some ideas that can make my curriculum even more rigorous. Reproduction, genetics, biotechnology - hot topics that it focused on in addition to the usual ecology. We have already great project-based units that encompass the topics, and I'm brainstorming on elaborating on them even more.

After some post-exam group reflection, the kids tell me that the Regents Community review really helped. They said that the talking and listening to how problems were done by their peers helped them recall information better. To some extent, they admitted that my ass kicking (making practice homework count as a quiz, pop quizzes, calling parents) helped.

Regents are over, time to do some real fun science!

Pizza Party

I have a runnning competition going between my two regents classes. On quizzes, tests, exams, etc., I average the grades and keep a tally of their scores for the individual assessment, plus an overall score. They have been pretty close thoughout the year with one class slightly ahead of the other. Then came the midterm exam, for which I promised the winner a pizza party. And one class really walloped the other, winning by 12 points. Today they got their pizza party and needless to say, the other class cried foul. Nevermind that I've been on their case lately for not putting in the effort and not having what I consider to be a proper work ethic for an "honors" type, accelerated, grade 8 regents biology class.

As luck would have it, that second place group is also my official class, and there's the whole "familial" dynamic here makes them feel particularly slighted. I don't know yet how I will remedy the situation. I really like my official class, but a significant number of students just want to party - clown around, make jokes, socialize, etc. I can't just reward them for nothing. And the thing is their behavior/attitude problems are an issue in homeroom period as well, and their conduct sheet is far from perfect. I would love to be able to just reward the students who do work hard and succeed, but there is no clear divide between the two groups - if you lined the class up and put the worst offenders on one side and the hardest working best behaved student on the other side, everyone else would fall along a continuum between the extremes, with no clear demarcation point between those who deserve to be rewarded and those who don't. Then of course there's the slacker who does well on the exams, and the hard worker who doesn't quite get it yet and fails the exams. It's just an impossible split.

I will discuss the issue with them tomorrow and see if we can come up with a plan. They will need to do something to earn the pizza - I don't mind spending the money once in a while or using class time if they work hard enough to deserve it. If the exam scores had been closer and their lack of effort weren't so obvious, I would have given both classes a party today.

Guest Blogger

Annie Chien is a high school science teacher of regents living environment at School of the Future in lower Manhattan. I have known Annie for a couple of years now, beginning with a class we found ourselves in at CCNY (Evolution). I had not seen Annie since that class, but after I subscribed to the NSTA Biology Listserv (NSTA members only - login required), her name started appearing in my e-mail box as she commented on various questions people had posed on the listserv. Annie stumbled upon my blog and and we have begun talking about regents living environment and some of the issues it poses in terms of, e.g., constructivism and inquiry. She has been teaching the course for six years now, and I welcome her input. I have asked Annie to be a guest blogger here, which she has graciously accepted. I will let her spell out any other professional/personal information she would like to share. Look for her post early this coming week.

Welcome Annie!