What happened to "h-bar"? Imagine my surprise when I'm looking through the new formula sheets for the new IB Physics curriculum, and I see the uncertainty principle as "equal to or greater than h/4pi." Over 4pi? When did that happen? I thought I was going crazy. My textbooks all say "over 2pi," and they are publications from 1999 and 2000 (not too old). Only this new text edition (sent as a sample) that was published in 2004 shows the 4pi. I guess this means we are twice as certain about things than we previously thought.