5D40.10 Jacob's Ladder

An arc rises between rabbit ear electrodes attached to a high voltage transformer. About 30,000V/cm needed to get current flowing in air gap. Glowing area heats air, reducing density,so it rises. 

Setup Requirements: Off the shelf. If it is slow to start rising, move your hand up and down over opening to vary air pressure in tube. The arc will ignite tissue paper. Have a piece of metal or wood handy to cover the hole once burning starts to avoid fire alarm going off.

Equations: None

Safety Issues: High Voltage, Flames. Do not touch electrodes when power on. Extremely high voltage may kill you. Keep students away. Turn off and unplug before opening to add paper.