What does rigor mean in a science course? How can it encourage learning and engagement? And how can we support students while maintaining standards of excellence? In this episode, we dig further into the topic of rigor with David Helfand, a faculty member at Columbia University for 45 years, who served nearly half of that time as Chair of the Department of Astronomy. Professor Helfand answers these questions and shares his thoughts on everything from curving, to what inspires him to believe in the possibility of change in higher education teaching.