The mystery tube is a fairly well known activity among science teachers for illustrating the nature of science. A variety of procedures have been presented for carrying out this activity, such as Scott Miller's method based on the BCSE 5E Instructional Model. Mystery tubes and other "black box" activities allow the students to engage in the scientific process without requiring any specific knowledge ahead of time. The traditional mystery tubes are designed simply enough that it is a viable activity even for elementary and middle school age children. That simplicity though means that high school and especially college science and engineering students might figure out too quickly how to replicate the behavior, and become more confident than we want them to be in their model. In this paper, I present a new version of the mystery tube that is complex enough to give strong high school and college science and engineering students a reasonable challenge, so they can better experience the ongoing process of science and the inherent uncertainty.