Theory:

In few scientific applications, it may required measuring the temperature higher than \(42\)°\(C\) and lesser than \(35\)°\(C\); in such cases clinical thermometers cannot be used. We need a laboratory thermometer in such cases.
Laboratory or Lab thermometers are the instruments that are used to measure the temperatures for scientific researches in schools and labs.
 
398px-Lab_thermometer_2.jpg
Fig. - Laboratory Thermometer
 
Lab thermometers are designed to measure the temperatures, the boiling point and the freezing point of substances. 
 
shutterstock_1566192313.jpg
Fig. - Experiment on Laboratory Thermometer
 
In industries, it is used to measure temperatures higher than what clinical thermometers can measure.
 
Structure of Laboratory Thermometer:
  • It has a long narrow tube (Stem) and bulb compared to the clinical thermometer.
  • There is no kink in the Laboratory thermometer.
Temperature Scale in Laboratory Thermometer:
  • It has only the Celsius scale ranging from −\(10\)°\(C\) to \(110\)°\(C\).
Important!
Precautions to be followed while using a Laboratory Thermometer:
  • Do not tilt the thermometer while measuring the temperature. Place it upright.
  • Note the reading only when the substance from all sides  has surrounded the bulb.
  • Make sure that the bulb should not touch the bottom or sides of the container.
  • Do not move the thermometer while doing the measurements.
Difference between Clinical and Laboratory Thermometers:
 
Parameter to be compared
Clinical Thermometer
Laboratory Thermometer
ApplicationClinical Scientific Research and Lab
UsesIt is used to measure the human body temperature.It is used to find out the boiling point and freezing point of the substances
Range\(35\)°\(C\) to \(42\)°\(C\) / \(94\)°\(F\) to \(108\)°\(F\)\(10\)°\(C\) to \(110\)°\(C\)
StructureMercury level does not fall on its own, as there is a kink near the bulb to event the fall of mercury level.
Mercury level falls on its own as no kink is present.
WorkingTemperature can be read after removing the thermometer from the armpit or mouth.Temperature is read while keeping the thermometer in the source of temperature, e.g. a liquid or any other thing.
RestorationJerks are given to lower the mercury level.No need to jerk to lower the mercury level.
 
Reference:
Image credit:
https://commons.wikimedia.org/wiki/File:Lab_thermometer_2.JPG