In the March 2020 issue of TPT Kenneth W. Ford examines rainbow formation by refraction and internal reflection(s) of light in rainwater droplets.1 Since the formation of rainbows is usually presented and taught with other related phenomena of ray optics, like total internal reflection, it is worth pointing out something not mentioned by Ford—that in rainbow formation there is never any total internal reflection. To help prevent student misconceptions, this should always be kept in mind in teaching about rainbows or writing physics textbooks.
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