SOCS-I Minstrell (Explaining the "at rest" condition of an object)

So, I have to say I was glad to have a shorter assignment tonight.  There must be something about reading heady articles at night in the summer time as a teacher, but I am finding it really hard to concentrate.  Anyway, this article was a nice easy read I could agree with.  I always have a ton of difficulty with the normal force, or as my kids all call it (regardless of what I call it) the "Natural Force."  Anyway, I spend a lot of time talking about it, but nothing seems to help.  I am not sure why I never thought of it, but having kids come up to the front and hold out their arms while I put books in them seems AWESOME.  I mean, how obvious, and yet this simple demo has eluded me for years.  I am excited to do this next year.  I think my students will immediately see the connection.  Maybe I am just fooling myself though :)  This year, in our discussions on the normal force, it came up that contact forces kind of don't exist.  I asked what our skin is made out of.  They said protons, neutrons and electrons.  Then I asked, what about the table.  Same answer.  Then I said, do you think these things interact with one another?  Then I asked, so....do you think you can actually "touch" anything?  They absolutely freaked out!  It was awesome, and it continued to be a topic of conversation all year.

SOCS-I Arons 2.8-2.16

S, in reading these sections of Arons, it became clear to me that he finds it very important to go over the base meaning of things over and over again.  That is, as we have been doing in class quite regularly, he thinks we should not just come up with a operational definition of a concept and move on.  He thinks we should force the students to think through simple examples like, if a ball is going up at 30 m/s, how fast will it be going in one second, two, three, four... and so on.  I think I am going to incorporate more of this into my classroom, but I wonder if my students will become tired of that kind of interaction.  I feel like after the first response the rest can come quite easily even if there is not a clear understanding by everyone in the room.  Perhaps the time at the top will cause difficulty, but otherwise, I see my students being frustrated by the slower pace.  Of course, I also feel like I am falling into the typical trap of a physics teacher-  If we clearly stated what happens, they must understand it now.  So, I intend on trying this repetitive process next year to see what kind of response it garners, and what kind of effect on understanding it has for the group.

SOCS - I (Hammer "Two approaches to learning Physics")

So after reading the Hammer article I find myself linking his two example kids to my own students.  I would actually be happy with either kid, as both seem motivated to learn.  Liza seemed to me what I call a memorizer, and Ellen a conceptualizer.  I wonder what a group of those two together would do for both of them.  This article makes me think of what I am doing in my classroom unknowingly to support students like Liza, as most of my "good" students follow this model.  I also wonder what I could do to help students like Ellen to gain organize and connect her conceptual thinking to her mathematical methods of problem solving.  There has to be a middle ground, and I have to support learning there.

SOCS-C Mestre "Learning and Instruction in Pre-College Physical Science

The Mestre article got me thinking about the Millikan Award acceptance speech by David Griffiths in 1997.  Both authors spent some time discussing textbooks.  Griffiths worries that spending more time developing concepts in the classroom necessitates students learning more "information" outside of class from the textbook.  He points out that, not only do many students find it difficult to learn from a text, but that most texts are not designed to present material without the guidance of a gifted instructor.  Mestre has similar things to say, I think.  He argues that the textbooks merely present a list of facts and problems for students to memorize and complete.  I agree that textbooks in physics are poorly written for high school classes, but it does get me thinking about how I picked up the conceptual understanding I currently have.

I seem to have arrived at a conceptual understanding through solving problems in textbooks without much direct guidance.  Then I would ask questions that came up through my solution, or more likely, I would be graded on a problem and realize my error.  Over time, and through repetition of this process, I gained the understanding I now have.  Through many failures and successes I have learned something that I do not think I could have learned without both the failures and the successes.  Science is hard, but it feels good to overcome a conceptual road block.  I think it is important to realize in all of this, that my expectation of my students cannot be mastery in the first run through.  Perhaps I need to reevaluate my goals/assessments looking forward.  I need to make sure my expectations of my students are in line with my reaction to my own experiences as a student.

SOCS-P (Arons 2.1-2.7)

So, reading Arons and his discussion of a "clock reading" as having zero length in time causes difficulty for me.  I immediately struck up a text message stream with my physics professor from college discussing this idea.  I will share it tomorrow in class with anyone if you are interested.  For me, if I am interested in describing instantaneous velocity and acceleration, I must inherently be discussing TWO TIMES.  Therefore an "instant" is by default a very small change in time.  Arons expressly states that an "instant" has no "length in time" just as a point has no length in space.  I guess this is semantics, but I really think it would hinder a discussion of any kinematic topic other than position.  To describe a velocity or an acceleration, two moments in time are needed, and both are the rate of change of one quantity per unit change of another.  If I go about describing an instant as being a single time with no "change" than I feel like I would have difficulty describing to a student why the "instantaneous acceleration" of an object at the top of its path is not zero.  I always talk about the fact that we are interested in two times, however close together they are, and an object will only be at rest one of those moments.  The acceleration will not be zero because the velocity is changing between those TWO times.  I have always described it this way, and I talk to my students about the fact that "instantaneous" really is an "average" over a very small time period.  I look forward to discussing my difficulties with my group tomorrow.  I have named this a "Philosophical" SOCS because I feel like this is a philosophical discussion, not a matter of curriculum or instruction.  I could imagine it being an instructional SOCS, but I guess I feel it is more about belief than practice.

Arons 1.1-1.12 etc

SOCS - I
After reading the first few sections of Arons "Teaching Introductory Physics" I am feeling pretty good about what I have been doing in my class.  In one instance he talks about requiring students to tell the story about what 2.3 g/cm^3 means.  This is a standard practice for me.  I still think I can get better at leading students as a group to ask these same questions of each other, but I feel like I have at least recognized that there is a need for this verbal reasoning.  Now I just need to improve at leading/guiding the students to their own revelations.

SOCS-I The extended cut

"How We Teach and How Students Learn" (McDermott)
After reading this article, I am resolved to improve my teaching practices.  I can think of times during the year where I have worked to move away from direct instruction, and I have spent a lot of time discussing the types of situations described in the article.  For instance, the discussion on the brightness of light bulbs resonated with me.  I spent some time, after working through Kirchhoff's Rules,Ohm's Law, and graphing the current as a function of the voltage across a resistor and across a light bulb, discussing specifically the brightness of a light bulb.  In particular, I think it is difficult to describe what it is that makes a light bulb bright.  Is it the current through the bulb, or the voltage across it?  It is pretty clear, based solely on practical experience, that a 100W bulb is brighter than a 40W bulb in the home, but how does that relate to a set up in our lab.  I think the brightness of a light bulb is a complicated topic- perhaps more complicated than this article claims it is.  There are so many assumptions made in the typical questions that aren't necessarily obvious or true.  For instance, it is always assumed that the power rating of each bulb is the same, and that the resistance of the bulbs will be unchanged as the bulbs are added, removed or their connections are changed.  So, we talk about these sorts of things in my class, but gaining a good conceptual understanding of the brightnesses of bulbs in circuits is actually VERY difficult, and I am sure I do not have a clear model.

Now, I can answer the questions as long as I am willing to go along with the aforementioned assumptions, but I feel empty here-like I was "taught to the test."  As my students and I walk through our conversation on this topic, I feel like I am teaching to some future test for them (not mine.)  But I do wonder why the teachers at large seem to be in agreement that determining the brightness of a light bulb is somehow simpler or at least more approachable than finding the power dissipated by a resistor.

Now to a light bulb question I can really get excited about, can anyone provide a reasonable and (here's the kicker) simple model to explain the brightness of a 40W bulb connected in series with a 100W bulb?  I think I can do it, but it is going to require me to pull out the big guns, and if my students and I got into that conversation, a good many of my students would be running for the door.  Determining the current in that circuit would be a nightmare.  I mean, what is the resistance of a 40W bulb... connected in series with a 100W bulb?  I dunno, the wattage, as stamped on the bulb describes the wattage when the bulb is connected to 120VAC.  That will not be the case when it is in series with a 40W bulb.  Anyway, I digress.

I look forward to developing methods in this workshop that will allow me to walk with my students through questions, explanations and model building such that they gain a stronger understanding of the concepts of physics.  I have spent a lot of time in recent years making sure my test and quiz questions are assessing the kind of thinking and learning I am interested in seeing in my students.  Now, I hope that this workshop will help me make sure that my students' experiences in my class will better develop the kind of thinking and understanding I am looking for on my assessments.  I made this a "Instructional" type SOCS because I feel like I need to work the way I approach topics, and the way I lead students toward the light without pointing it out to them.  The workshop has been modeling that wonderfully for me, and I am so excited to practice these methods more.

And seriously, if you have a model for my light bulb question, I would love to talk about it with you.