Fire In The Bowl!

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I was clicking through a collection of photos I’ve downloaded from my camera, but hadn’t quite gotten around to sorting around yet, when I came across this picture.  It may not look like much, but it sparked a bit of a commotion last Fall. 

This photo is of the remnants of a suspected spontaneous combustion.

The episode started harmlessly enough, with Fall clean-up.  It was a nice, warmish, September day here in Ontario- maybe 75 degrees tops- probably one of the last warm weekends of the year, so everyone wanted to be outdoors.  The kids were helping me wipe down the patio furniture and put it into storage for the winter.  The clean up crew was using an ordinary, old rag dishcloth, a stainless steel mixing bowl and plain water from the hose- no soap or chemicals.  So far, sounds like the perfect picture of suburban mundane.  I was in the yard the next day to let the dogs out when I noticed the kids had left the mixing bowl outside.  When I went to pick it up, I found it as it appears in the picture.  The remaining wash water was gone and the bowl contained the charred remnants of the washcloth and serious scorch marks that seemed to indicate an intense fire.

I’m pretty sure my kids aren’t little arsonists in training, although the thought of objects spontaneously bursting into flames in the back yard did pique their interest.  We only have one set of matches in the house (for the BBQ and fireplace), they’re kept well out of reach and the kids have been taught well that they don’t play with them.  I seriously doubt any of my neighbors is getting their jollies by setting my precious rags on fire.  Which means the prime suspect is the stainless steel bowl- is it possible that the bowl acted as a parabola and concentrated the sun’s rays sufficiently to boil off the remaining water and then ignite the cloth?  To me, it seemed unlikely, given the time of year- meaning a trend toward shorter days and more oblique sun rays in the Northern hemisphere.

Hitting The Google it seems like it could be the case, though.  Campfire Dude, for one, illustrates all sorts of ways to ignite things using the sun with unexpected objects on his website.  Some of these might be worth playing with once camping season is underway.

It’s a little early yet, but now that the winter’s finally over, we’re prepping to see if we can recreate the phenomena.  I’ve got an identical bowl and I’m willing to sacrifice another dishcloth in the name of science.  I’ll keep you posted.

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