I built a little toy wheel out of recycled cardboard box, wood glue, some staples, and a paper clip axle. I think it's going to be helpful when we discuss the relationships among rotations through a fraction of a circle, degrees of central angles, and arc lengths.
I also made the wheel 3-D (with thickness of about 1 inch) so that we will be able to easily wrap some yarn around it to verify our conjectures about the relationships between arc lengths greater than the circumference and the number of revolutions and the degrees traveled.
Excited! Love tactile toys! (Even simple ones that don't look flashy and that I build out of empty cardboard boxes after kicking out a family of spiders previously residing in the box.)