Optically Worked Double Convex Glass Lens, 75mm Diameter, 300mm Focal Length, Alternate Model Capacity_125mL Illustrates liquid-density changes with temperature

Illustrates liquid-density changes with temperature using a weighted 75mm hollow copper sphere that floats in 15°C water and sinks as the water warms to 30°C

this low-current 2mA buzzer on a demonstration base sounds whenever current flows through the closed circuit

the cylindrical concave curvature spreading light along a single axis for line-focus and divergence demos

suited to transferring crucibles around open-flame chemistry work

retaining field strength across years of classroom handling

Optically Worked Double Convex Glass Lens, 75mm Diameter, 300mm Focal Length, Alternate Model Capacity_125mL Illustrates liquid-density changes with temperatureAlternate model 75mm double convex glass lens at 300mm focal length, the optically worked surfaces and ground polished edges parallel to the main line 300mm focal lens for backup stock use.