Magnetism

An amateur educational film explains the principles of magnetism

A discordant blast of piano heralds the start of the film, over abstract colours. The piano settles down into a rather overbearing rhythm, and the title appears, followed by quick-cut shots of different types of magnets attracting various metal objects. The rather young-sounding narrator then begins an introducing to the principle of magnetism, which starts off simply but then becomes rather complicated to non-physicists. Over static close-up shots (which form the majority of the film), a hand demonstrates the use of an induction motor, showing how magnets can rotate without touching. We then see depictions of lines of magnetic force, using the old iron filings on a piece of paper trick. Numerous rules and laws of electromagnetism are explained in turn, using the same static camera shots, one-coloured backdrops and hand-made and operated diagrams. Some of the concepts explained are solenoids, ferromagnetism, paramagnetism, diamagnetism and Quincke's Method. We see a wider shot of an experiment, filmed in a lab, to show the change of ferromagnetic material to paramagnetic, known as the Curie Point Experiment. Once the experiment has been completed, the piano music fades back in, and we see panning shots of the old Mathematics and Physics building at UEA, and then one of the window to a student's bedroom in the ziggurat. A student, presumably one of the filmmakers, then proceeds to write the film credits onto his window using white paint. The final shot is of a window looking out towards another ziggurat with 'The End' in the top left corner, before a curtain is literally drawn across the scene.

Featured Buildings

Mathematics and Physics building, UEA; 'ziggurat' UEA

Keywords

Magnetism; Physics; University of East Anglia

Background Information

In physics and materials science, the Curie temperature (Tc), or Curie point, is the temperature at which a ferromagnetic or a ferrimagnetic material becomes paramagnetic on heating; the effect is reversible. A magnet will lose its magnetism if heated above the Curie temperature. The term is also used in piezoelectric materials to refer to the temperature at which spontaneous polarization is lost on heating. An analogous temperature, the Néel temperature, is defined for antiferromagnetic materials. The Curie temperature is named after Pierre Curie. Below the Curie temperature neighboring magnetic spins are aligned parallel within in ferromagnetic materials and anti-parallel in ferrimagnetic materials. As the temperature is increased towards the Curie point, the alignment (magnetization) within each domain decreases. Above the Curie temperature, the material is paramagnetic so that magnetic moments are in a completely disordered state. [wikipedia]