During a human science class for younger students, the teacher asked the students what part of the human body could grow to six times its size at certain times. A little girl raised her hand and said, "Teacher, you know my daddy's a preacher and you know we don't say those words in my house. You are just trying to embarrass me." Next he called on Johnny and Johnny said, "The iris, it grows to six times it size when you are in the dark." Teacher said, "That's right Johnny." Then said, "Little girl you have a very dirty mind, and when you grow up and get married one day, you are going to be very disappointed."