I am fascinated my the art and science of measurement. Just how do we accurately measure time or voltage.
Temperature is elusive - a lot more than people think. We did not have a standard fluid-filled thermometer until the 1740's and any accuracy beyond a tenth of a degree was not developed until the mid 1900's.
Stand back! From Phys.org:
World's best thermometer made from light
University of Adelaide physics researchers have produced the world's most sensitive thermometer – three times more precise than the best thermometers in existence.Published in the journal Physical Review Letters, the researchers from the University's Institute for Photonics and Advanced Sensing (IPAS) report they have been able to measure temperature with a precision of 30 billionths of a degree.
"We believe this is the best measurement ever made of temperature − at room temperature," says project leader Professor Andre Luiten, Chair of Experimental Physics in IPAS and the School of Chemistry and Physics, pointing out that it is possible to make more sensitive measurements of temperature in cryogenic environments (at very low temperatures) near absolute zero.
Time (frequency, etc...) has always been the easiest. Voltage is kind of hard. Temperature is the difficult one...
