alcohol is not used in thermometer
. Mercury is used in it.
Why do we use alcohol in thermometer?
Alcohol thermometers are used rather than mercury thermometers in very cold regions because
alcohol has a lower freezing point than mercury
. Pure ethanol freezes at -115 degrees C, while mercury freezes at -38 degrees C. Thermometers rely upon thermal expansion of the liquid in a bulb at the base of a thin glass tube.
Why alcohol is not used in thermometers?
Explanation:
The boiling point of ethanol is +78 ∘C
. This limits the top measurement of the thermometer to this temperature. Of course, the MELTING POINT of ethanol is −100 ∘C or so, which allows measurement of temperatures lower than 0 ∘C .
What Cannot be used in a thermometer?
Water
is not able to be used as a thermometer liquid because of its higher freezing point and lower boiling point than the other liquids in general. If water is used in a thermometer, it will start phase variation at 0∘C and 100∘C. This will not help in measuring temperature, beyond this range.
Is mercury or alcohol used in thermometer?
Mercury is the only one in liquid state at room temperature. It's
used in thermometers
because it has high coefficient of expansion. … It also has a high boiling point which makes it very suitable to measure higher temperatures. Also, it has a shiny appearance and doesn't stick to the glass surface of glass.
How accurate is an alcohol thermometer?
Alcohol thermometers are also inexpensive and durable.
They are typically not as accurate as
mercury thermometers because of the alcohol's susceptibility to evaporation, polymerization potential and capillary separation. Their primary advantage is safety to humans and the environment.
What liquid is used in thermometer and why?
In a
mercury
thermometer, a glass tube is filled with mercury and a standard temperature scale is marked on the tube. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. Mercury thermometers can be used to determine body, liquid, and vapor temperature.
Why is it not advisable to sterilize a clinical thermometer in hot water?
6 replies. Clinical thermometers have a very small range, being from 20oC to 45oC in general. If placed in boiling water, which is 100 degrees,
damage will be caused to the thermometer
, either melting it or changing the properties of the catalyst inside.
Will it be alright if water or oil is used in thermometer?
It won't be alright if
we use oil or water in a thermometer as these liquids will stick to the capillary tube of the thermometer and won't give right measure. Mercury has got the high coefficient of expansion than most metals and also with oil and water.
What is poor thermometric liquid?
Merhcey: water cannot b used as a thermometric liquid only bcos
it wets glass
and nt bcos it is a poor conductor.the liquids used in the thermometer do not wet glass take mercury for example.
Why mercury and alcohol is use in thermometer?
There is a technical reason for using mercury in clinical thermometers.
Mercury has a greater coefficient of thermal expansion than alcohol
. This means a column of mercury will expand and rise more than a column of alcohol for the same temperature change. As a result, you can get finer readings with mercury.
Do alcohol and mercury thermometers read the same?
The operation of these two thermometers is based on the thermal expansion of a fluid. Both mercury and alcohol have different thermal expansion.
If both fluids have a thermal expansion coefficients that vary linearly with temperature then they will always show the same reading
. Otherwise the readings will deviate.
What's the normal temp for a human?
The average normal body temperature is generally accepted as
98.6°F (37°C)
. Some studies have shown that the “normal” body temperature can have a wide range, from 97°F (36.1°C) to 99°F (37.2°C). A temperature over 100.4°F (38°C) most often means you have a fever caused by an infection or illness.
What are the disadvantages of alcohol thermometer?
| advantages disadvantages | Alcohol thermometer (compared to a mercury thermometer) | lower freezing point (-114 C) less durable (alcohol evaporates) | larger coefficient of expansion alcohol can polymerise | less hazardous fluid loss by evaporation hard to avoid |
|---|
Can a alcohol thermometer be wrong?
Yes the accuracy of a liquid in glass
thermometer can absolutely change over time
. It's usually due to slight (sometimes permanent) changes in the bulb volume or changes to the glass capillary (small cracks, glass annealing).
What is major drawback of thermometer where alcohol is used?
Disadvantages. It
is less durable because alcohol evaporates faster than mercury
. It cannot measure high temperature because of a low boiling point. It wets the walls of the thermometer, which can adversely impact the accuracy of readings.
