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Weird Science: John Dalton, Atomic Theory and Color Blindness


SF. Fig. 1.7.  Images from the Ishihara color perception test. People with normal color vision will see numbers in each circle. The numbers are, clockwise from top left, 2, 12, 42, and 6.

Image adapted from Wikipedia


Most scientists today specialize in very narrow fields of study. A scientist may be an expert on a single species of urchin that is only found in Hawai‘i or on how one specific type of molecule, like chlorine, reacts with other molecules to form new compounds. In the past, however, scientists were often much more generalized in their studies. John Dalton, an English scientist (born 1766, died 1844) studied a range of topics, including light, the English language, meteorology, gases, atoms, and color blindness. Dalton is famous for his Atomic Theory.


In addition to his work with gases and atoms, Dalton also was one of the first people to study and describe color blindness. Below is a simple test for color blindness. Can you see the numbers hidden in the circles of dots in SF Fig 1.7?


Dalton himself was colorblind and his pioneering work led to the use of the word Daltonism as a synonym for color blindness.

Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.