The magnetic properties of an object and its interaction with an external magnetic field can be described through the magnetic (volume) susceptibility χV, which divides nearly all kinds of matter into diamagnetic, paramagnetic, and ferromagnetic substances. Quantitative measurements of χV are usually technically sophisticated or require the investigation of substances with high values of χV to reveal meaningful results. Here, we show that both diamagnetic and paramagnetic effects in everyday materials can be measured using only an electronic balance and a neodymium magnet, both of which are within the reach of typical introductory college and high school physics classrooms. The experimental results match related literature values remarkably well.
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Neodymium magnets can cause extremely strong attractive forces on ferromagnetic materials. Therefore, these very strong magnets should be handled carefully to prevent injuries or material damage. The official safety instructions must be followed.
It follows from the assumption that χV = χV,app represents the apparent magnetic susceptibility instead of the intrinsic magnetic susceptibility . For dia- or paramagnetic samples with , it is appropriate to approximate χV,int ≈ χV,app.
For samples being investigated as tiny beads with total volume we can deduce Eq. (8) using . Calculating the integral then leads to . This approximation is appropriate for a large number k of beads being homogeneously distributed within the sample holder up to its maximum height hh and leads directly to Eq. (8).
