This Eisco Labs Hollow Acrylic Semi-Circle measures 3" long, 1.5" wide, and 0.75" tall, with an indicator line marked halfway across the arc. The acrylic construction provides optical clarity for observing light behavior. Semi-circular blocks are used to demonstrate reflection, refraction, Snell’s law, total internal reflection, and wave phenomena. The flat surface acts as the refracting boundary while the curved surface ensures light enters perpendicular to the surface. Suitable for physics classrooms studying optics and light behavior.