Review for:Vernier Magnetic Field Probe

posted: on December 20, 2006 at 3:33PM

Magnetism

Introducing students to magnets and the concept of the magnetic field.

I used this in two ways. The first was to just simply measure the magnetic field around the magnet, and thus I was hoping to have the same kind of instant-feedback on magnetic fields that the motion detectors do for motion. The second was to get data on the magnetic field of a solenoid so that students could build the equation.

Honors or Advanced, Intro or Regular

Firstly: Students connected the probe to the computers (laptops) and the loggerpro software was used. Then they turned it on and moved it around in the Earth's magnetic field to see what the orientation was like. (finding a max B and a min B) Then they tried to use it to map the magnetic field of a cow magnet and a disk magent. (They were also supposed to map the mag field of a solenoid, but we ran out of time.)
Secondly, I had a slinky set up with current running through it (connected to a powersupply and an ammeter) and the mag field sensor was inside the slinky (which was acting like a solenoid.) The students changed the current thorugh the slinky and found the related magnetic field. Then they changed the length of the slinky, keeping the current constant, to see how this affected the magnetic field. They went home and used excel to make linearized graphs of B vs. I and B vs. 1/L, and we worked in class the next day to combine those two graphs into the solenoid equation, B = u I N / L to see if they got close to u with their constant!

Provides visualization or animation, Increases mapping skills, Increases data collection & analysis skills, Provides access to data that is hard to measure otherwise

Probes worked very well. They relied on relativly strong fields, but the lowest setting got us data in the mT range, which was fine for the lab. Instant feedback on the first part was great, data for the B vs. I part worked well, data was a little tough for the B vs. 1/L part as the probes moved (they needed to be zeroed at the beginning, but when the slinky shrunk they shifted a bit.)

Range? Set up time? (Took an hour.) They were pretty straightforward. Cost... 56 per is tough for a once-a-year lab.