This week, Reddit was shook when one user shared a cautionary tale of accidental fire at their home. Not by an unattended candle, or a frayed wire, or even unventilated electronics—but by a doorknob.
Reddit user Proteon shared a photo of a burned wall that was caused by the sun shining through a glass doorknob:
And it's not just doorknobs that can cause damage: Jars, mirrors (and mirrored furniture), fishbowls, crystal balls and other objects, glass bottles, and even eyeglasses can cause damage when left in the sun.
Light, when refracted through glass objects, can get hot enough to start a blaze. And while the it's not a large cause of fires by any means, it does happen regularly enough for the London Fire Brigade to comment on it. They stated in 2015, after a Nutella jar caused a serious fire, that 125 light refraction cases had been reported in the last five years. And that's just one city.
"This shows these fires are not an urban myth," said Charles Pugley, an investigator for the Brigade. "Also make sure that you have a working smoke alarm on every level of your home."