Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy near-collimated for astronomical analogue and

near-collimated for astronomical analogue and long-throw projection setups

Document analysis kit teaches forensic investigation through ink chromatography

Eight aluminum-shank tuning forks tuned to scientific pitch (C4 = 256Hz) and ranging from 5 9/16 to 7 1/8 inches

Converts chemical energy to electrical through a zinc-copper-sulfate redox couple

Alternate-model 75mm double-convex glass lens at 300mm focal length

Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy near-collimated for astronomical analogue andCast iron 500g mass carries a retractable hook for suspension from spring scales, pulleys, or beams, serving as a replacement piece for gravitational and force measurement setups.