President Siebert: Mrs. Latham, I'd like you to meet three of our outstanding young researchers. This is Dr. Leonard Hofstadter, Dr. Rajesh Koothrappali and Howard Wolowitz.
Mrs. Latham: Well, what happened to you, Wolowitz, couldn't stick with it long enough to get your PhD?
Howard: I'm an engineer. Most engineers don't bother with a PhD. But you may be interested to know I designed the zero-gravity waste-disposal system for NASA.
Mrs. Latham: Got it. You're a space plumber.