Rolling Into Radians
Student groups collect height versus distance data for rolling objects of different sizes. Each group produces two sinusoidal graphs of the data, one in which both axes are measured in units, and the other in which both axes are re-scaled and free of units. Students note that the amplitude and period of the unit-free graph are the same for all groups, and then discuss how their measurement opens a different way of describing points on a unit circle.
Interactive Unit Circle
This is an interactive model of the Unit Circle. Features include a moveable slider to change the values of central angles in radian measure.