Restless Earth Geology Teaching Model Light & Optics_Color Wall-mounted Mason's hygrometer with two

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

sized to drop straight into the student electrolyzer without rewiring for inert-electrode investigations of water decomposition

this universal charger keeps portable instruments running between sessions without rotating in fresh disposable batteries

this pipette-type hydrometer draws electrolyte into a glass body with a colored-zone float for direct reading

Restless Earth Geology Teaching Model Light & Optics_Color Wall-mounted Mason's hygrometer with twoWall mountable Earth dynamics model depicting sea floor spreading, subduction zones, continental interiors, and mid ocean ridges, each structure individually labeled for plate tectonics units.