US$ 57.00
field lines
fabricated from glass tubing 6 mm bore
Mounted Zener diode on a transparent base with 4mm color-coded sockets and a printed circuit diagram
wheel-and-axle
Combining filtration and titration on one base
Ring and Ball Apparatus with Stand Glass Bottles_BOD Bottles field linesStand 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.