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Why does the liquid in a thermometer go down before the temperature is taken?
Wiki User
∙ 14y ago
It does not by itself. It must be shaken down.
The liquid is Mercury, which is very heat-expansive, i.e. it changes its volume noticeably and quickly depending on its temperature. The warmer, the larger the volume. That's why it's used in thermometers. However, thermometers are built so that the mercury does not go down by itself to enable taking precise readings (otherwise, it would fall quickly immediately after the thermometer is removed from the body). So, the thermometer must cool and the contracted but vacuum-stuck mercury must then be shaken down to take another measurement.
Wiki User
∙ 14y ago
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Why does the liquid in a thermometer move?
It doesn't 'move' exactly, it expands. Originally mercury (a metal in a liquid state at room temperature) was used in thermometers; as the the temperature increases the mercury (or other liquid) expands, taking up more of the volume within the thermometer, causing the level to rise. Thermometers are calibrated to allow the temperature to be measured based on how much expansion has taken place.
Why lab thermometer do not have kink?
the temparature of the liquid must be read while the thermometer is in the liquid.since the level of mercury drops as soon as the thermometer is taken out of the liquid ,therefore no need of the kink in thermometer.
Does mass affect equal volume how it falls through a liquid?
The only way that the mass can change is if matter is added or taken away. The volume of a liquid can increase if heated, such as the liquid inside of a thermometer. The thermometer is sealed and no liquid gets in or out, so the mass of the liquid is unchanged. But when the temperature goes up, the liquid expands and is forced to go up the thermometer.
Why is Mercury used in thermometeres?
Mercury is a liquid over a wide range of temperature ( -39 to 357 degrees ) so it can be used in a variety of temperature ranges. Secondly it does not stick to the glass tubing of the thermometer so when the temperature falls ( i.e. after the reading is taken) all the mercury falls back into the reservoir. This ensures the accuracy of the mercury thermometer.
Why does the expansion of glass in liquid-in - glass thermometer ignored?
For the basic principle, it can be ignored, since the liquid expands more than the glass.For exact calculations, the expansion of glass must also be taken into account. In practice, however, you'll want to calibrate the thermometer with known temperatures (for example, the temperatures of freezing and boiling water) - in which case such calculations are both unnecessary and useless.
How does an ear thermometer measure the temperature?
An ear thermometer should be placed carefully in an ear to measure the temperature. The temperature is then taken by an infrared mechanism in the thermometer.
Why does the liquid in a thermometer move?
It doesn't 'move' exactly, it expands. Originally mercury (a metal in a liquid state at room temperature) was used in thermometers; as the the temperature increases the mercury (or other liquid) expands, taking up more of the volume within the thermometer, causing the level to rise. Thermometers are calibrated to allow the temperature to be measured based on how much expansion has taken place.
A thermometer is taken from a room where the temperature is 20C to the outdoors where the temperature is 5C After one minute the thermometer reads 12C When will the thermometer read 6C?
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Why lab thermometer do not have kink?
the temparature of the liquid must be read while the thermometer is in the liquid.since the level of mercury drops as soon as the thermometer is taken out of the liquid ,therefore no need of the kink in thermometer.
Why can't you drink 30 minutes before taking your temperature?
If your temperature is taken orally, the temperature of your drink can change the reading on the thermometer. If your temperature is taken rectally or in the axilla, then it wouldn't matter how long it as been since you drank something.
Why is a clinical thermometer usually shaken after use?
Well, a clinical thermometer is shook after use so that the mercury comes back to its initial point i.e. where it had been before the temperature was taken.
Explain how a liquid thermometer measures temperature?
OK basically depending on what thermometer. the glass tube is filled with either alcohol or Mercury. and when it gets hotter, the liquid expands and takes up more space inside the tube. and colder.......the liquid compacts and moves down the tube.....and it's taken years to calabrate the markings on the tube to show the correct reading.
How is temperature taken through an oral placement?
The procedure for taking a patient's temperature by mouth with a mercury thermometer is similar to the axillary method except that the silver tip of the thermometer is placed beneath the tongue for four to five minutes before being read.
Does mass affect equal volume how it falls through a liquid?
The only way that the mass can change is if matter is added or taken away. The volume of a liquid can increase if heated, such as the liquid inside of a thermometer. The thermometer is sealed and no liquid gets in or out, so the mass of the liquid is unchanged. But when the temperature goes up, the liquid expands and is forced to go up the thermometer.
Why is Mercury used in thermometeres?
Mercury is a liquid over a wide range of temperature ( -39 to 357 degrees ) so it can be used in a variety of temperature ranges. Secondly it does not stick to the glass tubing of the thermometer so when the temperature falls ( i.e. after the reading is taken) all the mercury falls back into the reservoir. This ensures the accuracy of the mercury thermometer.
Is a thermometer a example of an independent variable?
Absolutely, the thermometer is independent of any other measuring device, therefore the actual temperature is dependent on the reading that is taken off the thermometer.
Why is it best to take temperature readings in the shade?
A thermometer is not kept in direct sunlight because the temperature needed to be recorded by the thermometer is of the air and not the rays of the sun.
