I've been working on teaching my first grade classes the names of the bones in the body. They are quizzed orally at the end of class, with students calling out the answers as a group. One day, as we were going through the quiz, I asked the students the name of the bone in the arm that starts with the letter "R" and they called out "Radius". Next question...what's the bone next to it that starts with the letter "U"? There was a long pause, with students trying to remember the answer, when one student calls out "Uterus!"