Hope your school year is going well. I am looking forward to our annual VIP spring meeting at UVA later this month. It is coming fast! Hope to see everyone on April 30. Be one of the first 20 to RSVP and reserve your Make N Take kit. This meeting we will be building a longitudinal slinky wave machine courtesy of Greg Matthes.
In this month’s newsletter there is a lot to discuss. A big thank you to Frank Noschese of Action-Reaction, John Burk of Quantum Progress, Rhett Allain of Dot.Physics, and Shawn Cornally of ThinkThankThunk. With permission, I am reprinting some of their recent thought-provoking blog posts. Every heard of pseudoteaching? How about Khan Academy? Ever thought of teaching acceleration with a Wiimote? I hope you find something here that will get you thinking about your teaching and encourage more innovation in the classroom.
President, Virginia Instructors of Physics (VIP)
Who: Physical Science, Physics teachers, and University physicists.
When: April 30th (time agenda below) 8:30 AM – 3:00 PMWhere: Department of Physics Jesse Beams Laboratory, University of Virginia
382 McCormick Rd
Charlottesville, VA 22903
There is a good web map at http://www.virginia.edu/webmap/GMcCormickRoadArea.html The physics building is #41. You may want to park behind #38 off of stadium road. Do not park at the physics building. This is 24/7 permit parking.
RSVP IF ATTENDING – FIRST 20 GUARANTEED MAKE AND TAKE EQUIPMENT – firstname.lastname@example.org
Spring Meeting Agenda (April 30th 2011)
In this Issue
February 21, 2011 by Frank Noschese
So what did MIT do after Lewin’s show-stopping lectures failed to change declining attendance and large failure rates? They created interactive learning spaces like TEAL, which stands for Technology Enhanced Active Learning. From the New York Times article “At M.I.T., Large Lectures Are Going the Way of the Blackboard”:
Teachers and students conduct experiments together. The room buzzes. Conferring with tablemates, calling out questions and jumping up to write formulas on the white boards are all encouraged.
I admit I was “doin’ the Lewin” my first years of teaching. I was up late each night, creating Powerpoints and crafting worksheets. All students had to do was follow along and fill in the blanks. Then I’d work a problem on the chalkboard and the students would finish the rest for homework. The next day, the whole cycle would repeat with a new topic. I planned lessons by answering the question “What am I going to do in class tomorrow?” Now, I plan lessons by answering the questions “What are my students going to do tomorrow? How will it help them progress towards our learning goals?”
What’s your pseudoteaching story?
February 21, 2011 by John Burk, quantumprogress
Scene: Hunting Monkeys and Pseudoteaching
My example of Pseudoteaching is super fresh. This week, I decided to do an exercise where we explored the famous monkey hunter problem. In case you haven’t seen it, here’s the basic setup. A monkey is hanging from a tree, a height above the ground. It’s a nervous monkey, and so it will drop from the tree at the same instant it hears any disturbing noise. You’d like to shoot a banana at the monkey (yes, this problem has been sanitized from its previous monkey hating roots), and you are a horizontal distance away from the landing spot of the monkey. You wonder how you should aim at the monkey if you want to hit it with the banana. Should you aim at the monkey, below the monkey, or above it?
So I drew this diagram on the board, and started by asking my students to tell me what the velocity of the monkey should be.
As I usually do, I asked the students to explain how to draw as many graphs as possible for these two objects. And we quickly got to the following velocity graphs.
From these graphs, I ask the students to write the equations for the x and y positions of these objects, assuming an origin at the starting location of the banana.
Then I ask what must be true if the banana is to hit the monkey, and the students tell me that the x and y positions must be the same at the time of impact. So we write
They also see that the last equation can simplified to
Now we have two equations that relate describe the motion of the banana
With some coaxing, my students see you can solve the first equation for t_i, to get , and this can be substituted into the second equation to get
Which rearranges to
We stop and puzzle here, since this seems to be relating the horizontal and vertical components of the velocity to the initial height and distance of the monkey. I say, “to a physicist, this says ‘aim at the monkey!’” How can we see this? I get them to draw a triangle for the initial velocity of the banana and its components:
Soon my students see that the ratio and are just the tangents of and must be the same:
And the only way this can be true is if , so you aim at the monkey!
Breakdown: Why this is Pseudoteaching
After the lesson was over, I felt great. I’d basically run through this on the fly, and everyone seemed to be participating and understanding. I stopped along the way to make sure everyone was following the discussion, and to pick apart the particularly difficult parts. Courageous students asked good questions when they couldn’t follow, and I was sure that I’d made my former professors proud.
Then the next day, I decided to see how well my students could do this same derivation on their own. So I gave them this follow-up worksheet:
And as soon as they started working on it—I head the questions start rolling in:
“Wait, what are we supposed to be doing?”
And boom—it hit me. Yesterday’s great lesson really wasn’t much more than me showing off my algebra skills. Students were saying the right things when I paused long enough and gave them enough hints to get to the right answer like Clever Hans, but there’s no way they were learning this to symbolically reason through a challenging problem, which was my goal.
Pseudoteaching rears its ugly head right in my classroom. Ugh.
This experience taught me a vital lesson. If I want my kids to be able to reason their way through difficult problems, using symbolic reasoning, I can’t teach it to them by walking them down the narrow road of my “enlightened” physics understanding. Since this is how almost all of my physics classes were in high school and college, and I turned out ok, I thought this would be a great way to learn from time to time. Of course, I forgot how poorly I understood physics when I graduated from college and started teaching. I didn’t figure out most of these things until I was forced to puzzle through them on my own as a teacher.
I need to make time and space in my teaching for students to take on challenges like with this, struggle with them, get lost, fail, and keep going until they get to the solution. So that’s what we did. My classes worked on this for more than half an hour. A few got right to the finish, and were able to then try to figure out how high off the ground the monkey would be when it got hit. Others really struggled to figure out how to interpret their graphs to get equations, but got there in the end, and a few never finished, and I need to find a way to give them more opportunities and scaffolding so that they, too, can see success.
February 21, 2011 by Rhett Allain
Pseudoteaching is something you realize you’re doing after you’ve attempted a lesson which from the outset looks like it should result in student learning, but upon further reflection, you realize that the very lesson itself was flawed and involved minimal learning.
If you have been teaching (or facilitating learning as I like to call it) for quite some time, you have to have noticed this. Just because I clearly explain something on the chalk board does not mean that everyone gets it.
I like to use the example of a uni-cycle – which I actually don’t know how to ride. Suppose I was riding a uni-cycle in front of the class and showing all sorts of tricks. Would this help the students learn how to ride it? No.
I have a couple of examples of pseudoteaching – which I still do from time to time. Actually, I can do something that could be both pseudoteaching and facilitating learning. Here is the scenario. Suppose I solve a conservation of momentum problem in class on the board. For students that have looked at this kind of problem, this might be a great opportunity to ‘fill-in the missing parts’ of their understanding. Sometimes lectures are great for learning.
Now take this exact same situation. Say there is another student in that same class. This student has not yet worked on conservation of momentum. For this student, the presented solution might seem to make sense. However, I doubt it will really help in that student’s understanding.
Pseudoteaching in Lab
Here is another example. When I first started ‘teaching’ lab courses, I tended to write (or borrow) my own labs and post these online. Then for the first 30 minutes or so of the lab class, I would go over what we were going to do that day. It isn’t difficult to realize that this mini-lecture at the beginning does nothing to help them.
Now, I post the labs and give a 5 minute lecture. At the beginning of each class I let students ask ANY questions about the lab material. Often it is clear that they have not yet read or prepared for the lab. In this case, my lecture would be useless (except to waste time). If there are no questions, I might give some brief tips on specific equipment use (like be sure to clamp this thing down).
Overall I am happy with this new format. I still have students that aren’t sure what to do, but it is clear that they should read the stuff beforehand. It also gives me more time for individual interactions with students.
Pseudoteaching in Blogging
Yes. I said it. Blogging is my last strong hold of pseudoteaching. Really, this is just like the lecture thing. Is it possible that my blog posts could be useful? Absolutely. Could the help the student that needs help right before the test? It is possible, but highly unlikely.
So, the blog posts can be a form of pseudoteaching – but it depends on who you are.
If no pseudoteaching, then what?
I understand that it seems like there is nothing to do but lecture. Moving away from a pure lecture based course can lead to some awkward moments. Actually, this happens to me all the time. I tell the students:
“Ok. You need to read chapter 3. The text does a pretty good job explaining this stuff. Also, here is some extra online stuff that might help. You don’t have to completely understand this material, but if you don’t even try you will be lost. In class we will do more useful things.”
Then, in the next class I will maybe give the students some problems to work on. It is partially painful to see students just sitting there with no idea of where to start and not even asking for help. It is clear that some of these students are not prepared. Maybe I should give them a lecture on the material they didn’t read. Should I? If I do, they will never read this stuff before class. This is awkward time.
So, here is my typical class time recipe:
If you want to look at some more examples of pseudoteaching, Frank should be keeping a list of posts on his site.
· Khan Academy and the Effectiveness of Science Videos http://www.veritasium.com/2011/03/khan-academy-and-effectiveness-of.html
· Khan Academy is an Indictment of Education http://fnoschese.wordpress.com/2011/03/30/khan-academy-is-an-indictment-of-education/
by Shawn Cornally on May 5, 2010.
My secret objective is for them to think of an idea and follow it to fruition in a scientifically meaningful way. That’s it.
I’ve introduced Energy Conservation already by this time in the course, and the next towering giant to be seen is Newton’s Second Law. I know some of you will find this approach to be crass, but my kids don’t seem to benefit from the traditional way that physics is presented.
Why wait to introduce these huge ideas until kids have done all sorts of kinematics and other mathematical abstractions? I know the standard arguments for book structure, and I disagree: We’re always “preparing” them for the most important idea. Screw that. Give them the important ideas and flesh them out as the year goes on. Things will start elementary (i.e. Just KE and gPE) and move into complicated abstraction as their understanding follows. Energy conservation and F=ma are pretty much the only things I want my kids to remember, so why not stress them throughout the whole course?
How to teach F=ma, the eternal quandary. So simple, vital, and nuanced. I know it hinges on their understanding of acceleration. Acceleration in turn is one the trickiest topics to teach, not because it’s hard to manage, but because everyone comes with misconceptions about it. English usage of words like acceleration, velocity, speed, and their ilk are totally muddled. I need kids to understand the differences between them. I need them to understand how units underpin the connection of math to the sciences. I need them to reject their current misunderstandings about the magic pushes and pulls that comic books and movies have shown them.
This type of teaching towards misconceptions is not new, but I think it bears reminding. If you ask a student why something continues to move after you’ve thrown it, they will often respond with something quite cobbled and illogical:
“Well the force from my hand is like still pushing it in the air, and when it runs out of force, it falls to the ground.”
Yikes. A little evidence for the maligned “ontogeny recapitulates phylogeny” theory (which is a bit bunk, just to be clear): This child is positing Aristotle’s position, and she doesn’t even know it! This theory worked for a few centuries, but in the end it just doesn’t match all the data we have today about how things move. Our current most-used theory connects force to acceleration. That is, if something doesn’t feel a force, it doesn’t change speed. Whether from stop to go, or from fast to slow, those changes require a force, and that’s that. If you’re not feeling it, you’re not changing it.
How can I address this misconception? Wii Remotes! What? Yes! Wiimotes happen to be the cheapest and most fun accelerometers on the market. There’s a slew of websites dedicated to jail breaking and otherwise non-traditional uses of your Wiimote. I use a piece of software called DarwiinRemote.1 Kudos to the development team for this community-driven gem.
A quick Bluetooth sync (hit “Find Wiimote” and then hold down the “1″ and “2″ buttons on your Wiimote), and you’re up and running! Notice the awesomeness that is the real-time graph. Notice the fact that the Z-axis is offset by negative g when the Wiimote is sitting still. *Geek Out*
What using the Wiimotes gains me is a little street cred. and some serious connections to things that they want to know about. How does this thing work?2 How does it know what I’m doing? These are questions anyone has asked when interacting with a video game, let alone one as revolutionary as the Nintendo Wii.3
How does this go in physics class? We drop them. We slide them. We put wheels on them and make Wiimote cars. We put wings on them and throw them out windows. Whatever it takes.
We do a lot of great experiments with the Wiimotes. I generally start an inquiry cycle with them. My guided investigation is usually along the lines of dropping the Wiimotes, or attaching it to a pulley with a constant force. Anything I can do to help separate the ideas of acceleration, velocity, and force. The kids then think of all sorts of insane things to do with these. As I’ve said earlier, my goal is to start them off with something simple. Almost painfully simple really, in order to get them thinking about what could be cooler. My secret objective is for them to think of an idea and follow it to fruition in a scientifically meaningful way. That’s it. If it takes a short lame investigation to model a piece of technology, then that’s what I’ll do to get them thinking.
I’d love to hear your ideas about what you do with this! These Wiimotes come back all semester. What they’ve gained for me is a foothold when talking about F=ma at the board. (I spend more time at the whiteboard than you think). We’re always fighting to connect board ideas to real experiences. My favorite battle.
1. This is OS X software. If you have a PC, here’s a link to a similar program, but I don’t run Windows, so no promises.
2.The Wiimote is actually a camera with a Bluetooth transceiver in it. The sensor bar is a misnomer. It’s actually just two infrared diodes that shine into the Wiimote camera. The placement of the dots from the sensor bar in the picture taken by the Wiimote conveys where the Wiimote is, which it then sends back the Wii via Bluetooth. The accelerometer and other data are also sent to the Wii via Bluetooth. No information is actually sent to the sensor bar!
3. Shawn Cornally is not affiliated or being paid by Nintendo, but he wouldn’t mind it. I’d look great in blue overalls, or perhaps a green tunic…
Send us your blog url and we’ll add it to our list of recommended links. There are some really great teaching ideas out there.
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This newsletter and our spring meeting are graciously hosted by the Physics Department of the University of Virginia. The Make N Take session is funded by the Virginia Association of Science Teachers (VAST) of whom we are an affiliate and Jefferson National Laboratory. Spring meeting door prizes generously donated by Vernier, CPO, Sargent-Welch, Frey, Arbor Scientific.
Thank you for all you do to promote physics education in Virginia and beyond!
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