|Why is temperature so important for viscosity measurements? Do I definitely need a thermostat?
||The viscosity is very dependent on the temperature: A temperature change of 1°C leads to a viscosity change of approx. 5%, depending on the sample. This is why an exact tempering is required for measuring. Standards require an accuracy of tempering of ± 0,02 °C.
|Why is a separate control thermometer necessary if the thermostat shows the temperature at 0.01°C?
||The resolution of the thermostat of 0.01°C does not mean that the absolute temperature of the bath liquid is accurately set to ± 0.01°C. In order to adjust the bath temperature to an accuracy of ± 0.01...0.02°C, control thermometers with a low measuring uncertainty are required. The control thermometers by SI Analytics have a resolution of 1/100°C and can be certified (calibrated).
|Why does there have to be counter-cooling when working only slightly above room temperature?
||An exact regulation of the temperature is only possible, if the thermostat bath is heated and cooled simultaneously. Only if the measured temperate is about 20°C higher than the room temperature, the normal heat loss of the thermostat bath will be sufficient as a counter cooling.
|How exactly does the temperature constant need to be in the bath?
|| As per DIN 51562, ISO 3104 and ASTM D 445, the temperature uncertainty must not exceed ±0.02°C.