Black Body Oven

black body radiation - color/temperature relation

What it shows:
Black body radiators in thermal equilibrium should emit the same spectrum of radiation, so inside a kiln at high temperature objects should appear the same color whatever their material.

How it works:
Place a piece of brick and an iron ball into a kiln (ours is a Blue M Electric Co. kiln with 25cm × 12cm × 10cm oven) that has a temperature range up to around 1000°C. Close the door and crank up the temperature to maximum. Depending on the type of kiln, it will take around 20 minutes to reach equilibrium (a good length of time for a lecture). As soon as the door is opened there will of course be differential cooling, so the effect is clear only for a couple of seconds, so have the audience ready and waiting.

Setting it up:
Set the kiln up with the oven door facing the audience. Use a color camera with zoom lens to get a close-up of the interior while it’s cool. When the oven is closed and running, stop down the camera (f16 or f22) so as not to drown it. Make sure the camera is correctly color-balanced.

Comments:
Scrounge a kiln from your ceramics department and load what you like in it (check melting points first). Make sure the door is suitable for easy access and viewing. Rating ***