Over at Physics and Physicists, ZapperZ is thinking about the intro curriculum, and offers a suggestion:
I believe that we should have a more open-ended experiment to be given to the students. So I’ll give an example. Note that while thing is something that I’ve thought about for a while, I’m still writing this off the top of my head. So there may be other problems with it that I haven’t carefully considered.
Give them a problem to solve such as something like this:
Construct a pendulum clock. To make this clock useful, it would be helpful if the pendulum can swing back and forth once as close to 1 second as possible. Then each complete oscillation will take just one second. That way, this clock and measure time in increments of one second. You may use a stop watch to calibrate your pendulum to verify that it makes a one-second swing. Try to build this as accurately as possible. You must describe in detail in your lab report how you accomplish this task and why you chose to do it this way.
Now, as apparatus, give them a length of string, a set of weights, and a stop watch, plus other necessary items for them to be able to mount the pendulum on something.
He goes on to explain what he expects would happen in the class, and how this would be a valuable learning experience for the students. Go over there for the details.
I like this idea a lot. It’s a nice approach to the problems he explored in earlier posts. If I were teaching intro mechanics next term, I would definitely steal this idea.
Unfortunately, I’m not teaching intro mechanics, I’m teaching honors intro E&M. And I’m having a hard time thinking of analogous experiments for that material. This is why I have smart reader, though– do any of you have suggestions of analogous non-cookbook labs to do with an honors first-year E&M class?
Pulsed or mode-locked laser, vat of 2-photon fluorophore with a first-surface mirror at its far end, open aperture camera, all in the dark. Pop the laser, visualize the slugs of light as they pass through themselves. Length of slugs and refractive index yield timing. foot/(nsec)(refractive index)
The 4BL course at UCLA might have some useful information for you. This is an E&M lab course that was recently redesigned to incorporate exercises that allow (force?) the students to work out experimental problems on their own. The link follows, and once you are on their homepage you can find specific projects in the left menu.
http://www.physics.ucla.edu/class/eternal/4BL_STENZEL/notes/4BL-manual-html/index.html
It seems to me that much of the material of an intro E&M course is kind of difficult to do in this way. At least the first few weeks are generally basic concepts like charge, E fields, flux, and electric potential, and basic tools like Coulomb’s law and Gauss’ law; it’s hard for me to think of ways to do labs that illustrate these concepts that wouldn’t end up fairly cookbook-ish. But it never hurts to try. You might be able to do something interesting with getting the students to design some sort of experiment that shows that there must be two types of charge (something that’s often done in your usual cookbook labs but that might be adaptable to a less cookbooky form). Figuring out how to charge an electroscope without touching it with another charged object (i.e. bring a charged object close to it and then ground it) might be fun, although it would probably only be a small part of a lab. When they get to circuits, there’s always “Here are some circuit elements, build something that does X”, although with just resistors, capacitors, and inductors, the things they can make may be of limited interest. Of course, it all depends on what exactly gets covered in the course. I know the honors E&M course here at UW spends at least a couple weeks on special relativity, and I have no idea how you’d do an intro lab on any of that, cookbook or otherwise.
If you do come up with anything for your course, I for one would be very interested in reading about it.
I think an unlabeled component lab would be a fun and interesting way to do some of the circuit stuff in E&M.
Given a certain set of known components (LEDs which require such an amperage, power supply, etc), figure out what the rest of them (resistors, capacitors, wires which burn out above a certain amperage for effect, etc) are. Multimeters not allowed. Encourage some experimentation and keep a large box of extras for when components burn out.
We have adopted a similar line of thinking in our intro labs. Instead of providing them, though, with a task such as the pendulum clock, we provide them with a goal (either a measurement or a test of a particular mathematical model) and then let them decide to some extent how they are going to go about testing the model or making the measurement.
I found that this paradigm works very well in the intro E&M labs. I provide students with a goal- for example, measure the charge-to-mass ratio of the electron. Then, they get to figure out how to measure it given available equipment, what kind of data to take, how much to take, and how to process it. This same paradigm works well for other types of experiments such as:
1) measure the capacitance of a capacitor
2) determine if a device is an ohmic resistor
3) determine if the electric field is indeed uniform in a parallel-plate capacitor (model testing)
4) measure whether the electric force is proportional to 1/r^2 (model testing)
5) measure whether the magnetic field is proportional to a current (model testing)
It works very well to give students a pre-lab workbook that helps them work through some of the equipment setup and functioning before they come to lab. The students have responded well to the labs and I think we have better engagement and understanding in the labs.
Have you looked at the TEAL E&M labs at MIT? They have a nice set of visual EM field simulations which I believe are interactive and can be used as virtual lab apparatus.
It’s nice to see the fields directly during the experiments, though you would lose a bit of experience with cranky real-world equipment.