The Ever Exciting Sterling and Alex

Sterling and Alex go to Whitefish High School. They have been executing their experiment during Todd Spangler’s 2011 ADVANCED Chemistry class. Mister Spangler has been doing flour bomb experiments since the beginning of his teaching career. It is a tried-and-true experiment in the chemistry world, designed for teachers to impress their students. For how common-place these flour bombs may seem, Alex and Sterling still find them freshly exciting…

 The problem was that the candle for the flour bomb would never light up twice—so Alex and Sterling set out to solve the problem.  Along with getting consecutive results, we tried to see if other baking products would have an effect on the explosion.  Baking soda, corn meal, powdered sugar, white & wheat flour

Typically this experiment has always been done with white flour and a medium sift and candle. Every source we found on the internet provided the same steps, but we wanted to see if that was the most efficient way to procure a massive explosion. On May 2nd, 1878, in Minnesota there was the first famous mill explosion. It resulted from copious amounts of flour dust being produced in their factory. It takes one flame, and BOOM, the entire mill was in flames and 18 workers were killed. A similar thing happened with the Mount Mulligan Mine Disaster of 1921 in Australia; however, this resulted from coal dust.

National Fire Protection Association (NFPA) Combustible Dust Standards include:  Oxidant Concentration Reduction  Deflagration venting  Deflagration pressure containment  Deflagration suppression  Deflagration venting through a dust retention and flame-arresting device These standards are derived from safety precautions against more dust explosions.

PARTICLESIZE (microns) μm One inch25,400 Saw Dust Bone Dust Cement Dust Milled Flour, Milled Corn Coal Dust Sugars Oxygen * 1 micron = 1,000,000 th of a meter, or approximately inches

 Whole wheat has a micron size of 150, but a typical white ground flour has a smaller particle size less than 100 microns.  This affected Alex and Sterling’s experiment when trying to get consecutive lightings.

By alternating their controls, Alex and Sterling used many variables to try to find the best combination of strategies. INDEPENDENTDEPENDENT (CONTROL) Candle SizeFlour Type Sift Size Flour TypeCandle Size Sift Size Flour Type Candle Size

1. Melt candle onto wooden platform so stable 2. Light candle 3. Place 4ft PVC pipe over lit flame 4. Check by looking down to ensure flame 5. Fill chosen sift with specified flour 6. Sift the flour over open top of pipe 7. Continue until explosion 8. Scream with excitement 9. Repeat

TYPEDID IT EXPLODE?IF NOT, WHY?? White FlourDuh… Wheat FlourFor sure… Powdered SugarNopeToo dense, packed together instead of combusting Baking SodaNopeToo heavy and too fine Corn-mealNopeToo heavy, put out candle flame because of large particle size Bone Dust?YupIt just would

o Alex and Sterling concluded that White Flour with a Large Sift worked exceptionally well, when it comes to flammable baking products o The wide sift provided the largest surface area for the flour to expand into a larger cloud and combust o The small particle size of White Flour allowed more to billow into a proper dust cloud formation, and therefore explode in a bigger dust cloud

 Alex and Sterling also answered Mr. Spangler’s original problem: why the candle never lit twice  SOLUTION: After the explosion, the burnt flour remains on the wick. The candle will not light or maintain a strong enough flame for the second flour bomb. Between explosions, you must thoroughly scrape off excess burnt flour from the candle wick.

 Yes, their project is relevant.  Alex and Sterling’s project is a mini-scale example of what happens in massive grain/lumber/flour mills.  By identifying the most dangerous combination of variables for a PVC pipe explosion, we can identify what mills need to take more precautions against these flammable products Alex and Sterling have used the same concept that scientists do in preventing massive grain or wood factory explosions.

 Never experiment on a windy day; could result in person lighting on fire  Do not bother with 7ft PVC pipe; person will light on fire  If there is time and proper resources, actually try lighting bone dust on fire  Do project on a larger scale  See affect in giant mill

"Combustible Dust in Industry: Preventing and Mitigating the Effects of Fire and Explosions." Occupational Safety and Health Administration. Web. 25 May "The Cornflour ‘bomb’ - Experiments." Practical Chemistry. Web. 25 May "Everything You Always Wanted to Know about Flour Bomb." Relan.net. Web. 25 Mar Madrigal, Alexis. "The Explosive Truth About Modern Flour Mills | Wired Science | Wired.com." Wired. 04 Mar Web. 31 May "Particle Sizes." Engineering Tool Box. Web. May <