PURPOSE: To demonstrate that concave mirrors can focus heat waves.
DESCRIPTION: Two parabolic concave mirrors are used to focus heat from a nichrome heater and light a match.
(1) The heater is first placed about 50 cm from a match, but the heat is not intense enough to light the match.
(2) Placing one reflector behind the match so that the match is at the focus of the reflector will light the match in 10-15 seconds.
(3) Turn the heater around so that it is facing away from the match and use the second concave mirror to form a parallel beam of heat, which is then focused onto the match head as in step (2). The match lights in 6-8 seconds!
REFERENCES: (PIRA 4B40.10) See Demonstration Reference File for a TPT article describing this demonstration.
EQUIPMENT: Two parabolic concave relfectors, heater on mount, and match on mount.
SETUP TIME: None.
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