Reading Magnifying Glass, 50mm, 15cm Focal Length Gifts_Bar dropping resistance as temperature rises

dropping resistance as temperature rises and giving an introduction to temperature-dependent semiconductor sensors

Auxiliary accessory set for the demountable transformer system

this hair-element hygrometer uses fiber expansion and contraction on an 85 mm dial

Wooden-framed abacus with five steel wires and 20 beads per wire on a 13

Four-output regulated DC power supply providing +5V

Reading Magnifying Glass, 50mm, 15cm Focal Length Gifts_Bar dropping resistance as temperature risesPlastic handled 50mm reading magnifier with a 15cm focal length, doubling as a lab demo lens for focusing sunlight and investigating image formation with convex optics.