Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy bending measurably under heat as

bending measurably under heat as differential thermal expansion of the two bonded metals drives the visible curvature

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

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

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

the larger geometry pushing pole separation wide enough that field lines extend visibly beyond the magnet body for filing maps

Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy bending measurably under heat asCast 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.