Retorts

Roguish Reply

Your "Roguish Rhymes" comic strip [Nov 1996] describes the thermal impact on internal air temperature of a house caused by the proverbial black cat that sat on the mat in front of the fire. According to the author, the cat's "perfect black surface was absorbing all the heat of the fire" thus causing the heat deficit.

As all good science students who read NZ Science Monthly know, this would not be the case. Almost all objects in the room in front of the fire behave like near-perfect black bodies thus absorbing almost all radiant energy incident on them, cat or no cat, black or otherwise. The cat's presence in front of the fire would not noticeably affect the energy balance of the room.

Chris de Freitas, University of Auckland