Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy Converts chemical energy to electrical

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

Free-standing life-size male urinary tract model exposes kidneys

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

Document analysis kit teaches forensic investigation through ink chromatography

Seven-junction copper-and-iron thermopile from four 130mm wires of each metal

Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy Converts chemical energy to electricalCast 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.