Cobbler ball

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Shoemaker's ball from the Bergen-Enkheim local history museum
Shoemaker's ball in the workshop of a wood cutter, based on an original drawing by Hans Rüger
Schusterkugel in the Industrieviertel Museum in Wiener Neustadt

The Schuster ball (also Schuster lamp ) is with water filled colorless glass flask in spherical form to that was used by artisans in particular prior to the introduction of electrical light sources diffused light of the sun , a gas or oil lamp as a convergent lens to focus and so the Illuminate the workplace better. In this way, even the weak hours of the day during twilight could be used for work. In addition to focusing, filtering the heat radiation from the light source was a desired effect of the cobbler’s ball. So you could work with temperature-sensitive materials close to a strong light source.

variants

There were also changes to the cobbler's ball. Many of these spheres were hung around a light source in order to multiply its light, for example at holy graves in southern Germany and Austria.

At the end of the 19th century, Erwin Perzy experimented with shoemaker's balls to increase the light output, especially during operations. The light-scattering semolina added to the liquid did not lead to any improvement, but the first snow globe emerged from these experiments .

A smaller version of the Schusterkugel was used in early optical microscopes . The glass or crystal balls used for mantic by fortune tellers and spiritualists were often cobblers' balls.

Light distribution bottles

The opposite principle is used in the slums of Manila, for example as part of the Liter of Light project , to illuminate corrugated iron huts. The light from the sun is guided into the room through a hole in the corrugated iron roof of the hut using a plastic bottle filled with water and bleach . The bottle filled with water serves as a light guide that lets the sunlight penetrate through the opening and then diffusely diffuses it to all sides, so that the hut is diffusely illuminated by it. The bleach in the bottle is used to inhibit algae growth . In bright sunlight, the luminosity is roughly equivalent to the strength of a 50 watt light bulb, i.e. a luminous flux of around 600 lumens .

literature

  • Hannelore Dittmar-Ilgen: Why do soap bubbles burst? The shoemaker's ball (historical and physical). Hirzel, Stuttgart / Leipzig 2002, ISBN 978-3-7776-1149-5 , p. 125.
  • Roger Erb, Lutz Schön: The Schusterkugel. On the didactics of physics and chemistry, University of Kassel, lecture at the GDCP conference in Weingarten, 1990 (PDF, 3 pages).
  • Hans-Joachim Reupke, Wilhelm Schuldt: Physics, nature and technology. Partial volume 1, secondary level 1, pp. 165–167.
  • J. Kuhn, A. Müller, E. Plochich: Schusterkugel. Freehand experiments and everyday phenomena from the natural sciences. University of Landau , June 19, 2003

Individual evidence

  1. ^ Image of several cobblers' balls around a light source, accessed on June 20, 2018
  2. ↑ Shoemaker's balls around holy graves, accessed on June 20, 2018
  3. ↑ Snow globe manufacture - please shake vigorously once Deutsches Ärzteblatt PP 11, January 2012 issue, page 47, accessed on January 3, 2020
  4. ↑ Hans Walter Gruhle: Psychiatry of the Present, Part 1A: Basic Research on Psychiatry, edit. by J. C. Brengelmann et al .; Part 1B: Basic research on psychiatry, edit. by M. Bleuler et al .; Part 2: Basics and methods of clinical psychiatry, edit. by G. Bally et al. Springer, 1967 ( online on Google Books, accessed October 31, 2015).
  5. ↑ Malte Kollenberg: Light for the poorest: Bottle trick illuminates Manila's slums. In: Spiegel Online . September 4, 2011, accessed June 10, 2018 .