Ray box, simple, safe and sturdy source of projected light for many classic optics experiments, produces parallel convergent rays across a plane horizontal surface and the rays are intense enough to be traced in natural light. Built in solid aluminum extrusion casing, 100-240V 50/60 Hz
Water Treatment and Filtration, Environmental Chemistry, Includes: Fine sand, Coarse sand, Fine gravel, Activated charcoal, alum, lime, Green food coloring, Odor agent, Plastic cups, 5 Stirring sticks, used in examining the changes in the water due to pollution