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Magnétisme (in French) - Printable Version

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Magnétisme (in French) - adomps - 05-13-2020

Bonjour
J'ai utilisé Phyphox avec mes élèves pour mesurer le champ magnétique terrestre et celui d'un petit aimant. C'est un TP que j'ai mis au point pendant le confinement pour que les élèves le fassent chez eux. Très peu de matériel est nécessaire et les résultats sont quantitativement assez bons. L'énoncé est adapté à des élèves de premier cycle universitaire. Je fournis aussi un fichier de réponses avec mes résultats.


RE: Magnétisme (in French) - solid - 05-14-2020

Bonjour,

Très bien, peut servir chez nous aussi.

Hi
I would like to add some comments in English..

For your Python code it is better to read the data prepared as an ASCII file using np.loadtxt() - see a zip file that I have attached. So one should not change the code every time. I have allowed myself to replot your data... The code is simple, but not all our students can reproduce it.

It would be maybe better to use a smaller NdFeB magnet to approach it closer in order to have a larger interval of the distance r. One have to pay attention to  fridge magnets, they are usually magnetized in an alternating way to hook better (Halbach magnets).

[attachment=171][attachment=172]


RE: Magnétisme (in French) - adomps - 05-14-2020

Merci beaucoup pour ces remarques et suggestions.


RE: Magnétisme (in French) - julien - 05-15-2020

Merci beaucoup pour le partage de ton travail, c'est très intéressant !!!


RE: Magnétisme (in French) - solid - 05-15-2020

Bonjour

I have measured manually the same with TI SensorTag CC2650. I got too high value K = 1e7 µT/cm²  which gives too high value of J=9T..
The sensor has to be calibrated. Anyway the 1/r^3 law is verified.
[attachment=173]
P.S. I tried to measure B® automatically using a mouse, but failed - the mouse displacement was not correlated with the magnetic measurements. One more thing to be solved.


RE: Magnétisme (in French) - adomps - 05-15-2020

Very nice $1/r^3$ fit. I carried out measures with a SensiEdge Simba Pro bluetooth module and I got almost the same results as those given by the Phyphox app.


RE: Magnétisme (in French and German) - Boris Reusch - 05-20-2020

Very, very nice ideas, thank you!
Here I'have put a similar "home challenge" for my undergraduate students (in german)

We give them the "old school" double logaritmic paper, so they can show that the potential law is r^-3.
Best regards
Boris