Question

Why constriction is not present in laboratory thermometer?

Answer 1

⊕ Constrictions present in a thermometer are used for the following

О Constrictions prevent the level of the thermometric liquid to suddenly fall after measuring the temperature.

О The constriction hence conserves the reading of the thermometer for a certain period of time after which it falls .

О This allows the user to get enough time to read the readings of the level of the thermometer.

Θ Constriction are not present in lab thermometers

ОThe absence of constrictions help to measure the temperature readings accurately .

О In a laboratory the thermometer is generally required for measuring different instances of a chemical reaction

О The chemical reaction may change the temperatures very abruptly.

О Thus constrictions should interrupt the accurate and rapid changes in the thermometer.

О This also helps to read temperature in liquids because the temperature should rapidly change in such a case.

→ That's why constrictions are not present in laboratory thermometer

Hope it helps u :-)

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Answer 2

Old fashioned clinical thermometers had a constrictionb. This meant when you took the thermometer out of the patients mouth or wherever, the reading did not change. Otherwise it would have to be read very rapiudly or in situ!
You laboratory thermometer does not have a constriction so that when the temperature of something drops, the reading on the thermometer drops. Of course, you have to read it in situ. This is less of a problem if the thermometer is in a beaker of liquid.