I've always been intrigued by the story that the Greek scientist Archimedes used mirrors to focus sunlight on Roman ships and set them on fire during the siege of Syracuse. Is this true, or is it a myth?
Truth Or Myth?
Very cool question. And one that scholars have debated since at least the European Renaissance. Philosopher René Descartes, for example, rejected the story as a fabrication.
MIT And Mythbusters
More recently, a group of students at MIT tested whether or not Archimedes could have really burned Roman ships using mirrors.
On the TV show Mythbusters they used more than 120 one foot square mirrors to focus sunlight on a wooden ship at a distance of about 100 feet. They did manage to raise a flame and cause some charring. But only after the ship had been still for about ten minutes and the sky was perfectly clear.
More Of A Myth...
So, the Archimedes mirror story is probably more myth than real, for a few reasons.
First, for the plan to work, the Roman fleet would have had to attack in the morning, since Syracuse faces the sea to the east. This may have been the case, but there's no evidence that the Roman's carried off a morning attack.
More importantly, using mirrors to burn Roman ships would probably have been too impractical. It would have made more sense to use flaming arrows or pitch shot from catapults to set the boats on fire.
Still, Archimedes was an extraordinary inventor of, among other things, military machines. So while the mirror story is probably a myth, if anyone could have pulled it off, it was Archimedes.
Read More: Was Archimedes' Mirror Real? (NPR)