Ring and Ball Apparatus with Stand State_Solid Paired safety-socket outputs deliver two

Paired safety-socket outputs deliver two selectable ranges 0-70V and 0-125V DC at 300mA

Air-cooled rheostat at 36 ohms and 3A with constantan winding on a 300x44mm vitreous-enameled tube

1uF increments at plus-or-minus 5% on 63V

Rotation-to-linear gear-rack simple-machine model converting circular gear motion into straight-line rack travel

Sodium chloride lattice kit with 27 color-coded gray and green atoms plus 54 connectors for building the full cubic NaCl crystal structure in three dimensions

Ring and Ball Apparatus with Stand State_Solid Paired safety-socket outputs deliver twoStand mounted ring and ball thermal expansion apparatus, dropping freely through the ring when cool but stopped by the ring once flame heating expands the ball.