Jacob's Ladder
Safety Warnings
Danger: High Voltage Hazard
Warning: UV Radiation
Warning: Post-Demonstration Shutdown
Purpose
Demonstrates high-voltage electrical breakdown and plasma formation. Students observe arcs forming where the electric field exceeds air's dielectric strength, then rising due to thermal convection.
Figure 1:
Jacob's ladder with cylindrical glass safety shield in place. Two metal rods run nearly parallel inside the tube, with the transformer housed in the base.
Figure 2:
Arc forming between the rods near the base in a darkened room. The purple-blue color is characteristic of ionized nitrogen in air.
Figure 3:
Long-exposure image of the larger Jacob's ladder (currently out of commission) showing repeated arc cycles climbing between diverging V-shaped rods.
Figure 4:
The larger Jacob's ladder (currently out of commission) with V-shaped rods on a wooden box housing the transformer.
Demo Apparatus
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