Although I agree with the spirit of Doremus' write-up, there is a danger, when using discredited theories to teach modern science, of creating straw men, with the effect that good science may be bad history. Very often researchers, when presenting new theories, however good they may be, wittingly or unwittingly misrepresent the views of their academic adversaries.
An example of this is the straw man known as "Flat Earth theory". Whilst some people may believe this today, in reality educated Europeans in the middle ages knew the earth was round. The correct circumference of our planet had been calculated by the ancient Greek mathematician Eratosthenes in the 3rd century BC. During the middle ages, this was known and not disputed by the Catholic Church, and more importantly, by Portuguese sailors who traded as far away as East Asia. However, they did not know that the Americas existed, but believed the Atlantic and Pacific to be contiguous, and therefore too great to traverse.
Yet fate had it that Eratosthenes' calculations were disputed. Paolo Toscanelli (1397-1482) thought that earth was only about half as large as in reality, and Columbus, gambling on his miscalculations, sailed West. He believed he had found the East Indies when he had only reached the West Indies. The early explorers were indeed very fortunate they had reached the Americas rather than East Asia - at the time Chinese military technology was at least as advanced as their own, and gold was even more scarce in Asia than it was in Europe.
It's good to stand up for science, but we must take care not to misrepresent history in the process | 
