Cooling by Radiation

Most recent answer: 11/16/2012

Q:
A piece of ice and a warmer thermometer is suspended in insulated,evacuated enclosure so that they are not in contact. Why does the thermometer reading decreases for a time?????????????
- Syed Atif Rahman (age 18)
Islamabad
A:
Although the thermometer and the ice cube are not in intimate thermal contact,  due to the vacuum and isolation, there is an additional heat exchange due to black body radiation.  See: .  The thermometer, initially at a higher temperature than the ice, will radiate at a faster rate than the ice.   Eventually they have to come to the same equilibrium temperature. 

LeeH


(published on 11/16/2012)