Combustion of Donut in Liquid Oxygen

This experiment is not available beginning Summer semester 2005 due to incident of detonation and glass schrapnel reinstated effective Nov 13, 2006.

20061027 - Pending approval, not given effective 20061113, the experiment may be is reinstated. Items noted below in red are modifications to be strictly followed in response to the Spring 2005 incident.

Materials:
donut^* (standard glazed, use about 1.5 1.0 inch cube piece max)
Liquid Oxygen, ~1-2 L, in Dewar flask
Unsilvered Dewar Flasks (2)
beaker, 4 L
ringstand, ring clamp (4L size), iron ring
long tongs, bend as needed to use in conjunction with secondary shield for hand protection
Meker or Fisher burner
Fire Extinguisher
hearing protection
face shield
blast shield for class and experimenter
secondary shield for demonstrator for hand protection
Hazards:
Cryogenic - Liquid Oxygen
Oxidizer - Liquid Oxygen
Explosive - Liquid Oxygen (in presence of fuel)
Implosion - Glass Dewar Flasks
Detonation - ^*high density or too large piece of donut
Glass schrapnel - from beaker upon detonation, 5 meter radius minimum
Procedure:
Caution - use about 3 inches deep of liquid oxygen - donut should never touch bottom of beaker. Use of too large or high density piece of donut may (and has) result in detonation.
Smoldering donut will at times stick to the tongs, making it difficult to release the donut piece into the LOX. If the tongs are tapped on a protective ring just above the 4L beaker, additional downward velocity may be imparted on the donut. The additional velocity may promote an unplanned violent explosion. A metal rod, bent strategically, should be used to dislodge a sticky donut piece. Tong should be retracted promptly to prevent pressure build-up over beaker.

^* typical donut holes work well and are the correct size