Published in The American Biology Teacher, Volume 74, Issue 1, January 1, 2012, pages 10-14.
The definitive version is available at https://doi.org/10.1525/abt.2012.74.1.4.
The nature of scientific research sometimes involves a trial-and-error procedure. Popular reviews of successful results from this approach often sanitize the story by omitting unsuccessful trials, thus painting the rosy impression that research simply follows a direct route from hypothesis to experiment to scientific discovery. The discovery of insulin is a classical case study in this genre that begs for an explanation to our students because it is so often ignored or misrepresented even in biology and physiology textbooks.