Calibrating thermometers

[ldrchickens]

So i got 3 glass science grade thermometers and have been calibrating them today. I did the ice calibration and two read 0*c one read 1*c. Them i calibrated them using the boiling water method and they were reading anywhere from 105*c to 110*c. Is the boiling method not reliable due to different points at different sea levels. Or are my thermometers not reliable. I have tried over 10 thermometers and not a single accurate measurement. I am almost about to give up sadly.

 

[R2elk]

So i got 3 glass science grade thermometers and have been calibrating them today. I did the ice calibration and two read 0*c one read 1*c. Them i calibrated them using the boiling water method and they were reading anywhere from 105*c to 110*c. Is the boiling method not reliable due to different points at different sea levels. Or are my thermometers not reliable. I have tried over 10 thermometers and not a single accurate measurement. I am almost about to give up sadly.

For boiling water temperature to be accurate, it is necessary to know the elevation to make the temperature correction. The higher the elevation, the lower the boiling point is. The water has to be boiled in a container that is open and not covered. Covering the container will cause the water to boil at a higher temperature than expected. The water also should be distilled or deionized since water containing a lot of dissolved solids can have a higher than normal boiling point.

The thermometer needs to be suspended in the boiling water because allowing the bottom of the thermometer to rest on the bottom of the container can give false readings due to the proximity to the heat source.

Based on how high your readings are, you either have faulty thermometers or they were touching the bottom of the container and getting false readings from being in too close contact to the heat source.

Good luck.

 

[aart]

I test mine using a human medical thermometer in ~100°F water.
https://www.backyardchickens.com/ar...incubator-thermometers-and-hygrometers.73634/

 

[aart]

they were touching the bottom of the container and getting false readings from being in too close contact to the heat source.

Betting this is the problem.

For boiling water temperature to be accurate, it is necessary to know the elevation to make the temperature correction. The higher the elevation, the lower the boiling point is.

Yes.

Is the boiling method not reliable due to different points at different sea levels.

Google 'your town elevation'. Then use this calculator.
https://www.omnicalculator.com/chemistry/boiling-point-altitude

 

[ldrchickens]

Betting this is the problem.


Yes.


Google 'your town elevation'. Then use this calculator.
https://www.omnicalculator.com/chemistry/boiling-point-altitude

Thank you!