For the uninitiated, Marbleslides is a series of activities where students type equations into a graphing calculator. As soon as they hit "enter," a set of stars (or in this case, marbles) drops from the top of the screen. The goal? Adjust the equation so that the marbles’ trajectory—determined by the graph—collects all the stars.
It is notoriously difficult to explain why a graph has two separate branches. By treating the vertical asymptote as a physical barrier that the marbles cannot cross (and indeed, will slide away from), the concept of discontinuity becomes tangible. marbleslides rationals