SOUND : Sonometers, Tuning Forks, Resonance Apparatus, Resonance Boxes, Striking Hammers, Wave Propagation Apparatus, Ripple Tank, Slinky, Helical Springs and Wave Motion Apparatus, Organ Pipes, Melde's Apparatus etc LIGHT : Optical Benches, Optical Discs, Light Boxes, Lenses, Lens Holders, Mirrors, Slabs, Diffraction Gratings, Biprisms, Spectrometres, Vernier Microscopes, Telescopes, Direct-vision Spectroscopes, Slits, Biprism Assembly, Models of Periscopes, Telescopes and Compound HEAT : Conductivity of Heat Apparatus, Expansion Apparatus, Bimetallic Strips, Pyrometers Bar Breaking Apparatus, Calorimeters, Joule's Calorimeters, Steam Generator, Steam Heaters, Ring and Ball apparatus, Bar and Gauge Apparatus, Ingen Hauze Apparatus, Hope's Apparatus, Hypsometers, Latent Heat Apparatus, Thermopiles, Thermocouples etc