4C31.37 - Franklin's Pulse Glass Engine - Relaxation Oscillators

Place the pulse glass on the stand with the two attached light bulbs.  Turn the light bulbs on and turn the power supply up to 12 volts.  The light bulbs will heat one end of the pulse glass forcing the liquid into the other end.  When this happens the other end drops and is heated then by the light bulb on that side.  The cycle then repeats.
By putting the pulse glass on the stand you can make this work unattended. Fill the two beakers with liquid nitrogen and cover with the cork plates. The pulse glass will touch one of the beakers and the liquid inside will be condensed in the bulb that is touching. This will cause the pulse glass to shift position and then the other bulb will touch the beaker with the liquid then going to that bulb and so on.
Code Number:
4C31.37
Demo Title:
Franklin's Pulse Glass Engine - Relaxation Oscillators
Condition:
Excellent
Principle:
Vapor Pressures/Partial Pressures
Area of Study:
Heat & Fluids
Equipment:
Franklin's pulse glass, Stand for pulse glass, Small Plastic Beakers (50 ml), Liquid Nitrogen, Hand Boilers.
Procedure:

Video Credit: Jonathan M. Sullivan-Wood.

Place the pulse glass on the stand with the two attached light bulbs.  Turn the light bulbs on and turn the power supply up to 12 volts.  The light bulbs will heat one end of the pulse glass forcing the liquid into the other end.  When this happens the other end drops and is heated then by the light bulb on that side.  The cycle then repeats.  

By putting the pulse glass on the stand you can make this work unattended. Fill the two beakers with liquid nitrogen and cover with the cork plates. The pulse glass will touch one of the beakers and the liquid inside will be condensed in the bulb that is touching. This will cause the pulse glass to shift position and then the other bulb will touch the beaker with the liquid then going to that bulb and so on.

This demonstration is also a good example of a relaxation oscillator.

References:
  • James Lincoln, "The Hand Boiler and How It Does Not Work", TPT, Vol. 60, #3, March 2022, p. 232.
  • Paul Chagnon, "Animated Displays V: Relaxation Oscillators", TPT, Vol. 32, # 7, p. 432- 436, Oct. 1994.
  • H- 500:  "Palm Glass Oscillator",  DICK and RAE Physics Demo Notebook.
  • H- 73:  Richard Manliffe Sutton, Demonstration Experiments in Physics.
  • George M. Hopkins, "Air Thermostat", Experimental Science, p. 185.
  • Joseph Frick, "# 360 - The Pulse-Glass", Physical Technics: Or Practical Instructions for Making Experiments in Physics and the Construction of Physical Apparatus with the Most Limmited Means, p. 426.






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