Did Archimedes use a heat ray to set enemy ships on fire over 2000 years ago? A text written about the Siege of Syracuse (212BC) some 400 years later merely said he lit the ships on fire. He could have used flaming arrows or perhaps hurled larger balls of flame via catapult.
Anthemius of Tralles mentions burning-glasses as Archimedes' weapon.
This purported weapon has been the subject of ongoing debate about its credibility since the Renaissance
In 1973, an experiment using 70 mirrors, each with a copper coating and a size of around five by three feet, caused a mock-up ship 160 feet away to burst into flames within seconds.
A group of MIT students used a parabolic array of 127 "polished metal mirrors" 1 sq ft in size for a 2005 MythBusters episode and were barely able to set part of the "ship" aflame.
I recently came across this video of a recreation of the Archimedes heat ray experiment.