Fully Automated Light Scattering Experiment

thingiverse

A highly automated affordable educational lab experiment is designed to measure optical scattering, specifically polarization and angular cross-section, at a cost of just $50. This beginner-friendly setup is ideal for measuring light scattering by optical gratings, with the calibration process utilizing the well-known equation "grating_constant x sine(nth scattering angle) = n x wavelength" in relation to scattering from a CD-R surface. Developed in our laboratory physics courses, this experiment demonstrates Mie-scattering by microscopic colloidal particles. Mie-scattering refers to light scattering by objects comparable in size to the wavelength, which is typically used in expensive laboratory equipment to determine size-distributions of colloidal suspensions. The setup is controlled via an Arduino placed at the bottom of the device, requiring a small amount of soldering or a separate bread-board for assembly, which can be accomplished on an undergraduate or even school level. Detailed information, including a list of required components, assembly instructions and software (OpenSCAD files; Arduino Firmware; Python & Octave scripts for analysis of measurements - all GPL licensed) can be found on our dedicated website: http://www.mss.cbi.fau.de/Mie-experiment A live-demonstration of the measurement is available here: https://www.youtube.com/watch?v=A-WL2huUDuc The device was featured in the 3/17 German issue of the Make magazine: https://www.heise.de/make/meldung/Guenstig-dank-Maker-Technik-Optik-Experiment-fuer-Schulen-und-Unis-3716721.html For details on the experiment and explanation of the physics of Mie-scattering, we published a scientific paper here: C. Scholz, A. Sack, M. Heckel and T. Pöschel, Inexpensive Mie scattering experiment for the classroom manufactured by 3D printing, Eur. J. Phys. 37 055305 (2016) http://iopscience.iop.org/article/10.1088/0143-0807/37/5/055305 All parts were printed using an FDM printer (Kühling & Kühling RepRap), with PLA or ABS material used at a 20% filling and 80% for the base. Post-processing involves gluing and screwing together individual parts and electronic components, with some minor adjustments possibly needed to available servos, diodes, etc.