A professor at the University of Southern California gave Bryan Cranston lessons in chemistry basics for the series, so Cranston was able to correct some writer's mistakes. An actual DEA agent showed the crew and the cast how to make crystal meth. However, some steps were always omitted from the filming to avoid anyone using the show as a "how to" guide.
A plaque on the wall of Walt's home, says he did research in proton radiography in 1985, that contributed to someone's Nobel Prize win. The winners of the 1985 Nobel Prize for Chemistry were Herbert Hauptman and Jerome Karle, who won for their development of methods to determine crystal structures.
The show was originally planned to take place in Riverside, CA but was moved to New Mexico because the state offered an attractive tax rebate on production.
In the very beginning of the opening credits, the formula and molecular weight of Methamphetamine - C 10 H 15 N and 149.24, flash on the screen.