Jouni Valkonen <jounivalko...@gmail.com> wrote: > Thermometer must be calibrated in respect of boiling point of water (or > other known temperature that is relevant for what is measured) before it can > be used for accurate measurements. Without calibration, it's accuracy is > just ±0.4°C. But thermometer reproducibility is ±0.05°C and this means that > thermometer gives same reading with this accuracy in two consecutive > measurements. > Yes. Right. That's what I was trying to say, but you explained it better.
> As Mats Lewan calibrated the thermometer that boiling point was 99.6°C, > altough real boiling point in Bologna in that particular day was 99.9°C. > This is what it meas that thermometer accuracy is ±0.4. But relative > accuracy or precision or reproducibility is always higher in thermometer > than the resolution of display. In this case digits are by one decimal, > hence ±0.05°C accuracy. > Right. There is a small screw on the HH12B at the bottom marked "OFFSET." As I said, it adjusts to within a fraction of 1 degree. If Lewan had this thermometer he might have moved the temperature up to 99.9 deg C and then -- as you say -- it would go back to this in consecutive readings. It would be accurate to within a wide range of temperatures around 100 deg C. Precision is better than accuracy with thermocouples. That is to say, even if it is 0.4 deg C away from the real temperature (because you do not bother to calibrate) it can still measure a temperature difference of 0.1 deg C with confidence. - Jed
