Was I One Of The First To Have My Temperature Measured By A Thermometer Reading The Radiation From My Ear?
Last week, a doctor read my body temperature, by using an electronic thermometer, that read the temperature inside my ear.
But it wasn’t the first time!
That must have been in 1968 or 1969, when I was working at ICI in Runcorn.
ICI had a problem, in that they needed to read the temperature of chemical reaction vessels.
- Temperatures could be higher, than 1,000 °C.
- Some mixtures could be highly corrosive.
- Safety needed to be as high as possible.
My colleague; John Baxendale was assigned the problem.
John came up with a solution based on black bodies and their unique black body radiation.
These two paragraphs, from the Wikipedia entry for black body, explain the principle.
A black body or is an idealised physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. The radiation emitted by a black body in thermal equilibrium with its environment is called black-body radiation. The name “black body” is given because it absorbs all colours of light. In contrast, a white body is one with a “rough surface that reflects all incident rays completely and uniformly in all directions.”
A black body in thermal equilibrium (that is, at a constant temperature) emits electromagnetic black-body radiation. The radiation is emitted according to Planck’s law, meaning that it has a spectrum that is determined by the temperature alone, not by the body’s shape or composition.
Note, that I have very mildly edited, what Wikipedia says, to the King’s English.
John had developed some clever electronics, that read the spectrum of the radiation and by decoding the spectrum, he was able to calculate the temperature.
Early on in the testing, John found that nearly all of us, have two black bodies on the side of our heads; our ears, so he could measure the temperature inside them.
The Anonymous Widower 