Wood and Metal Cylinder for Thermal Demonstration Racks & Stands_Test Tube Racks and polished — letting an

and polished — letting an infrared sensor compare emissivity at boiling-water temperature

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

configured to make and break a circuit at the rhythm of a Morse-code transmission for telegraph-history demonstrations

Higher-range 30-0-30mA center-zero galvanometer at 20mA sensitivity and plus-or-minus 2

this Perspex acrylic rod gains a positive charge when rubbed with cloth

Wood and Metal Cylinder for Thermal Demonstration Racks & Stands_Test Tube Racks and polished — letting anHalf wood half metal 200 by 30mm cylinder demonstrating thermal conductivity differences through a wrapped paper that scorches over wood but stays uncharred over metal in flame.