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Why is a thermometer so thin?
The mercury inside is metal and an excellent heat conductor, but the glass is an insulator. So, for heat transfer improvement, the glass is made as thin as possible to speed up the copying of the temperature from the hot liquid to the mercury/spirit liquid inside the thermometer.
Why is the capillary tube of a thermometer narrow?
A glass bulb with thinner wall can transfer heat to the bulb easier. Therefore, the thermometer can response quickly to small changes of temperature near the surrounding. Capillary with narrow bore produces a greater change in the length of the mercury column.
What does narrow inner tube in thermometer is called?
The glass tube of thermometer is filled with mercury. It is a reflective liquid. It is bright and opaque, so it’s easy to see movement of mercury inside the capillary tube and to read accurately. Mercury does not even wet the glass. So, if temperature is falling then you do not get inaccurate readings.
What is the disadvantage of making the thermometer with very thin glass for the bulb?
The bulb of the thermometer needs to be thin because the glass, while a good material for most of the thermometer design, is a poor conductor of heat. The mercury inside is metal and an excellent heat conductor, but the glass is an insulator.
Why is the glass around the bulb of a thermometer so thin?
Glass has a very low coefficient of thermal expansion. This is the reason why thermometer bulb or for a matter of fact entire thermometer is made up of glass. Due to low coefficient of thermal expansion, when the thermometer undergoes a large temperature change it will have minimal change in dimensions.
Why does liquid in the thermometer?
The liquid in the thermometer goes up when the thermometer is heated because heating makes the alcohol molecules of the liquid move faster. The extra speed of the molecules competes with their attraction for one another and causes them to move slightly further apart.
Why thermometer has thick walls on its stem?
The stem has a thick wall because it has mercury inside it so when the the temperature rises the mercury bounces inside the thermometer.
Why the bulb of thermometer is small?
The small size of the bulb means that the bulb reaches the temperature of what it is measuring very quickly, and the tube in such a thermometer is micro-fine. Mercury also avoids the freezing and boiling problems associated with water.
Why is glass used to make thermometer?
The fluid/glass thermometer is the most popular thermometer used around the world to measure body temperature. It consists of a sealed glass tube with a small internal diameter (like a lumen) connected to a reservoir. Increasing the temperature expands and pushes up the fluid in the reservoir and tube.
Why are there long and short lines in thermometer?
These vertical (up and down) lines stand for degrees of temperature. Most thermometers have two scales for temperature, Fahrenheit and Celsius. Each long line is for 1°F temperature. The four shorter lines between each long line are for 0.2°F (two tenths) of a degree of temperature.
How can you tell if a thermometer is real?
Look closely at the parts of a thermometer. Look closely at your thermometer. The liquid inside is probably a type of alcohol that’s been dyed red. Practice reading the temperature in °C by having your eye at the same level as the top of the red liquid.
What is a laboratory thermometer used to measure?
Laboratory Thermometer. Since clinical thermometers can’t be used to measure temperature other than the human body, we need a special type of thermometers for other purposes. A laboratory thermometer, which is colloquially known as the lab thermometer, is used for measuring temperatures other than the human body temperature.
What happens when the temperature falls on a thermometer?
When the temperature falls, the liquid contract s and goes back down. Liquid thermometers often include both Celsius and Fahrenheit temperature scales, which are display ed on either side of the tube. A maximum thermometer is a familiar type of liquid thermometer.
What temperature can a mercury thermometer not measure?
Mercury, for instance, becomes a solid at -38.83 degrees Celsius (-37.89 degrees Fahrenheit). Mercury thermometers cannot measure temperatures below this point. Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 degrees Fahrenheit). They cannot be used to measure temperatures above this point.