Funny anecdote: the original PCR experiments were done with water baths at various temperatures. They manually moved the DNA samples from the boiling water (d

Funny anecdote: the original PCR experiments were done with water baths at various temperatures. They manually moved the DNA samples from the boiling water (denaturation), to hot water (55-ish degrees, annealing) to hotter water (elongation, 70ish) and then back to the boiling water for another round of amplification.