6-Piece Optical Lens Set, 3", Double Convex and Double Concave Base_Octagonal and 500mm focal lengths for

and 500mm focal lengths for comparative refraction experiments

Needle valve and flame stabilizer deliver fine flame control on this liquid propane Bunsen burner for precision chemistry and biology heating work

sized for pool

telophase — progress across this plant mitosis model for cell division teaching in biology courses

supporting three-rope compound arrangements for advanced mechanical-advantage investigations

6-Piece Optical Lens Set, 3", Double Convex and Double Concave Base_Octagonal and 500mm focal lengths forSix piece 3 inch optical lens set combining three double convex and three double concave glass lenses at 200mm, 300mm, and 500mm focal lengths for comparative refraction experiments.