Wooden Friction Block with Felt Surface, 6 x 3 x 1.25" Face Size_63mm 3 geometry stretching focal throw

3 geometry stretching focal throw for distant-screen projection of well-formed real images

Set of 20 different alloys supplied in wooden case with glass top

the lightweight body producing virtual upright reduced images for safer per-desk divergence demonstrations

and projectile-launcher kits

Standard 30° apex glass prism with 30° x 30° x 120° geometry

Wooden Friction Block with Felt Surface, 6 x 3 x 1.25" Face Size_63mm 3 geometry stretching focal throwPine wooden friction block at 6 by 3 by 1. 25 inches with felt on one face, a C hook at one end, and dual surfaces for comparative coefficient of friction measurement against spring scales.