US$ 28.00
the shared mass isolating volume and density as the distinguishing variables across metals and polymers
Reel of bare 18 SWG copper wire totaling roughly 80 feet by mass
5mm copper wire on a clear acrylic base support side-by-side comparison of how loop count multiplies the on-axis magnetic field at fixed current
and lead with densities from 2
Faraday's Butterfly Net Electricity & Magnetism_Circuits the shared mass isolating volumeDemonstrates that charge resides only on the outer surface of a conductor by inverting the charged net inside out and showing the charge transferring to the new outside layer.