Karst, Caves and Water Action Landform Model, 2-Part Type_Geographical the drilled aluminum ball gives

the drilled aluminum ball gives a lightweight contrast to steel and brass balls of the same size in pendulum period and momentum-transfer demonstrations

Snell's law

Large-format 150mm convex glass mirror at 150mm focal length and ~5mm thickness

Designed to generate and detect ultrasonic waves above the audible range

Wall-mounted Mason's hygrometer with two identical dual-scale thermometers — one dry and one kept wet via a water reservoir — calculating relative humidity from their paired reading difference

Karst, Caves and Water Action Landform Model, 2-Part Type_Geographical the drilled aluminum ball givesTwo part karst landform model with a removable surface that exposes caves, stalagmites, stalactites, and an underground lake, mapping 32 keyed features across the subsurface.