atomicfire - 23-5-2011 at 08:19
This may seem like an odd question but in a vacuum oven, how does the thermocouple measure the temperature if there is nothing to measure?
Mr. Wizard - 23-5-2011 at 09:12
It measures it's own temperature, which is determined by the balance of incoming and outgoing electromagnetic radiation. Alternately it could be in
physical contact with an object in the furnace. Heat is transmitted by convection, direct contact, and radiation. Convection is diminished as the
pressure drops, but it still exists.
A Dewar flask uses the reduction of convection by using a vacuum, reflective mirrors to reduce the electromagnetic transfer, and the thin glass to
reduce direct heat transfer up the throat of the flask.
atomicfire - 23-5-2011 at 10:14
My thermodynamics teacher would flip if he saw this.
I get it now, thanks. Just needed a little refresher!