If You Want to Teach Physic Lab Right, Skip the Manual

I was a graduate student when I taught my first class, a physics lab. There’s nothing unusual in this; university physics departments often hand labs over to graduate student. It’s a win-win, actually. Departments require teachers, and grad students require experience.

Of course, I didn’t really know what to do, but no worries. I could followa manual describingthe experimentations. In hour, though, my ideas about laboratories changed. It started after a presentation I considered at a conference. I don’t recall the conference or where it was, but I remember the talk. It was about inventions in lab. One of the speakers discussed an “improvement” to the electric fields mapping lab.

This is a common laboratory during second semester physics. The basic notion is to explore the electric field around an electric charge or between two electrically charged plates. It’s not easy to measure the electric field. Instead, youcheat and measure something simpler–conducting paper.

Image: Rhett Allain

The power supply connects to two points on black conducting newspaper. You can induce these connects in whatever shape you like–two points, or two straight lines, or any two-dimensional shape, truly. Utilizing a voltmeter, you can map out lines of equipotential and use that to calculate the electric field. That is the basic idea. As far as electricity-magnetism laboratory run, it’s not too bad in that students can use this electric potential to create a plot of the electric field.

But wait! Isn’t this lab super tedious( rather than just plain tedious )? That’s where thatconference talk comes in. One physicist came up with a modification: He’d have students use a probe to press various phases on the conductive newspaper. The apparatus would automatically record the voltage as well as the x and y-coordinates. Boom. Instant data without the tedious records. Better, right?

It was at this point that I realise the student was essentially eliminated from the lab. Awarded, the student probably was never truly was involved, but this induced itwas obvious. What started asan investigation into the relationship between electric fields and electric potential becamean exercise in data collection.

But what is the goal of a physics laboratory? I doubt all physics faculty will agree( and that’s OK ), but this is what I suppose an introductory physics lab should do:

Provide opportunities to experimentally explore physics theories covered in the lecture class. Demonstrate experimental design and analysis of data. Create theoretical models that agree with experimental data. Teach studentsto communicate scientific ideas( with lab reports ). Expose students to basic tools like avoltmeter, oscilloscope, and computer programming.