Cultures need to accurately record dates and times for various societal purposes, ranging from knowing when to plant crops to planning travel. In ancient times, the sun and moon were used as measurement devices because of the scientific understanding of the physical world at that time. Ancient timekeepers monitored celestial events and either used or discarded them, depending on whether or not they were useful as standard units. The lesson sequence presented in this article occurred during a 6th grade summer camp attended by students who had an interest in science. The purpose of the week-long camp was to offer explorations in science, mathematics, and computer programming. The team of university professors led the camp activities, which were developed in coordination with the students' regular classroom teachers.