Thermodynamics > Heat and the First Law > Radiation

DCS# 4B40.30

---

LESLIE CUBE

---

---

APPARATUS

Leslie cube	214-03-
thermopile	214-02-D5
DMM	214-01-B5
video camera	202-09-D

---

DESCRIPTION

Cube has faces with different surfaces heated to the same temperature by the light bulb inside.  Use the thermopile to compare radiant energy from polished aluminum, dull aluminum, black, and white faces to show that good absorbers are good emitters.

NOTES

 

Preheat cube 20 minutes before demo is needed.  Set power to 6.

Thermopile cover should be in place when it is not in use, otherwise it will heat up and change the reference temperature.

There is little difference between the white and black faces because the paints are fairly equally absorptive in the infrared, where the spectrum from the light bulb peaks.  A bigger difference can be observed between the shiny and painted sides.