Rectangular Refraction Acrylic Block, 100 x 75 x 18mm Subcategory_Microscope Slides this 80mm steel needle in

this 80mm steel needle in a 6mm rod doubles as a precise alignment reference for image-formation and ray-tracing setups

each 20mm on edge with a top hook for suspending in water during Archimedes-principle and buoyancy experiments

supplied with aluminum

5-meter bench on leveling-screw feet

Carefully lagged nickel-plated copper 3 by 2-inch inner cup inside a 4 by 2

Rectangular Refraction Acrylic Block, 100 x 75 x 18mm Subcategory_Microscope Slides this 80mm steel needle inPairs 100 by 75mm with 18mm thickness on an acrylic rectangular refraction block, the wider working face giving longer beam paths for clear refraction angle measurements.