5D40.15 • Conduction in Gases: Jacob Jr.’s Ladder

Location: Cabinet 2

Concepts Conveyed:

• Electrons repel and move from one electrode to the other
• As the arc heats and ionizes the air, it rises

Instructions / Notes:

• Place the power supply coil on one arm of the u-bend and the Jacob's Ladder attachment on the other.
• Add the additional metal piece across top and secure with bar/screw attachments.
• Turn on. If the spark does not travel, adjust the spacing of the electrodes with the small plastic lever. (Circled in white)
• DO NOT RUN FOR MORE THAN A MINUTE

Photo Shows the Demonstration Apparatus Used by the University of Texas at Austin.

Demo Staff:

• TEST THIS DEMO BEFORE EVERY REQUEST.
• If the spark is not lighting:
  • TURN OFF AND UNPLUG, then:
  • Remove screws labeled A and B and take out the back panel of the plastic case.
  • Sand each electrode, then replace the case and try again.

Last updated on June 8, 2026