The van used is the actual van that had been owned by Richard Feynman.
The recipe for thermite that Sheldon gives is inaccurate, in keeping with standard television practice not to show actual methods of producing dangerous materials.
Following her divorce announcement about her husband Ryan Sweeting, Kaley Cuoco's name in the opening credits were reverted to its original billing.
It is implied that Leonard already met both Penny's parents off screen, since Amy states that they both love Leonard.
Penny tells Amy, who wants to get her ears pierced, that she's done it several times by using a needle and an ice cube. Kaley Cuoco's on-screen husband, Johnny Galecki, used that same method to pierce his ear when he was ten years old because his parents wouldn't allow him to get it done professionally.