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arXiv · 1612.09563

Revisiting the round bottom flask rainbow experiment

Markus Selmke·Sarah Selmke
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Abstract

A popular demonstration experiment in optics uses a round-bottom flask filled with water to project a circular rainbow on a screen with a hole through which the flask is illuminated. We show how the vessel's wall shifts the second-order and first-order bows towards each other and consequentially narrows down Alexander's dark band. We address the challenge this introduces in producing Alexander's dark band, and explain the importance of a sufficient distance of the flask to the screen. The wall-effect also introduces a splitting of the bows which can easily be misinterpreted.

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Markus Selmke, Sarah Selmke. 2016-12-30. Revisiting the round bottom flask rainbow experiment. https://arxiv.org/abs/1612.09563

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