PURPOSE: To demonstrate focusing of heat waves by a concave mirror.

DESCRIPTION: The arc lamp with condenser lens produces a nearly parallel beam of heat. The parabolic concave mirror focuses the heat onto the match head, lighting the match in about ten seconds from a distance of about ten feet.

SUGGESTIONS: This one is a bit touchy and hard to work, so we suggest L3-16: FOCUSING OF HEAT WAVES BY MIRRORS as a better choice.

REFERENCES: (PIRA 4B40.10)

EQUIPMENT: Arc lamp with condenser lens, parabolic concave mirror and match holder on optical rail on rolling table.

SETUP TIME: 5 min.