2 x 4 Electroscope -- Versorium
Purpose
A 6-foot 2x4 balanced on an inverted watch glass rotates to follow a charged rod, demonstrating that charged objects attract neutral objects regardless of charge sign. Dramatically illustrates electrostatic induction at large scale.
Figure 1:
The 2×4 in motion (blurred) as it follows a charged rod held near one end. The board is balanced on an inverted watch glass on the green platform.
Figure 2:
Top-down view showing the 2×4 balanced on the inverted watch glass. The small contact area provides a low-friction pivot allowing free rotation.