The purpose of this activity is to allow students to think critically to answer a seemingly simple question. In this case, it’s answer an old idiom that implies that time speeds up when you’re having fun. The students will need to use the scientific method to determine a way to answer that question. They will also need to design a test to empirically show that relative to an activity, as opposed to space (as stated in Einstein’s theory of Relativity), time speeds up when you’re having fun and slowing down when you’re bored.
This is a great activity to make students really think about some fundamental principles of science. This can also lead into discussions about how the universe works and the potentials of time travel and how the universe works. Every time I've done this experiment, the students have always had a blast with the discussions.