Tuesday, April 10, 2012

Comparison of Alcohol and Mercury Thermometer

The word thermometer comes from the word thermos meaning warm and meter meaning measuring device. Etymologically, the thermometer is a device used to measure the temperature appropiate and express it by a number.
Thermometer is commonly made of a glass tube which is filled with liquids. The liquids are used as a thermometer filler, because the liquids undergo the change in volume if the temperature changes.

Commonly, thermometers use alcohol and mercury to fill their tubes, because alcohol and mercury have superiorities compared with anothers. However, there are also the weaknesses of alcohol and mercury. Meanwhile, if we compare between mercury and alcohol thermometer, we will find the superiorities and weaknesses of alcohol and mercury. Those are as follows:

Comparison of Alcohol and Mercury Thermometer

The Superiorities or the advantages of Alcohol:
  • It can measure a low temperature, because its freezing point is low (-115ºC).
  • It can measure the temperature precisely, because it has large expansion coefficient.
  • Its expansion is reguler.
  • less hazardous.

The Weaknesses or the disadvantages of Alcohol:
  • It cannot measure a high temperature, because its boiling point is low.
  • It makes wet the wall of its place.
  • It is colourless so it must be given dyestuff in order to be visible.
  • less durable (alcohol evaporates)

The Superiorities or the advantages of Mercury:
  • It is visible, because its colour is silvery shinning.
  • its expansion is regular.
  • It does not make wet the wall of its place.
  • It can measure the temperature quickly and precisely.

The Weaknesses or the disadvantages of Mercury:
  • It cannot measure very low temperature, because its freezing point is high (-40ºC)
  • Mercury is poisonous, so it harmful if its tube is broken.
  • Its price is very high. 
  • display is harder to read
  • cannot be used for thermograph
  • slow response
  • fragile  

--- Notions of English Disciple Blog is about Knowledge ---


  1. Alcohol is very dangerous,so need to quit and it causes so many disease and it spoils the life of the person.Intervention services

    1. whaaa? Its not like your going to crack open the thermometer and drink it all up and get drunk and lose your virginity!! gosh its a alcohol thermometer. alcohol is needed to heal wounds and all sorts so you cant ban alcohol because its a daily requirement for some people. not all (obviously #yolo) and we all know many people get drunk and allsorts but its cheaper and safer than mercury ANYDAY! mercury is poisonous when dropped it dissolves into the air and can fatally poison many people with that little quantity. alcohol any day.

      source: docter bride in physics and also docter Rowley in chemistry.


    2. #WORD
      My sources need updating + docter smita rao in physiology
      docter jamesion in marine biology.
      these questions came up in their daily life.
      all is well. all is well

    3. Read the comments above, and also consider that Mercury is far more dangerous than alcohol. A small amount can cause you very bad cancers.

    4. This comment has been removed by the author.

  2. I have one of the "Enviro-Safe" kind that I assume is filled with alcohol, and I want to get a mercury one. This page lists "slow response" as a weakness for mercury but I consider it a benefit! With my alcohol model if I am trying to get a reading in a cold setting, I have to be able to read it without touching the unit bare handed AT ALL. At 5 C the reading will sky rocket in a split second from being touched bare handed. It drives me nuts! And it is not even the full immersion type. I'm talking about when I pick it up at the far end away from where it reads!

  3. Its true that alchol is very dangerous but helpful too.Then why do we use alchol in thermometers than mercury?Mercury is of two types dry and wet we can use dry instead of wet if it is dangerous

    1. Mercury is a very toxic biohazard, and costs more than alcohol.

  4. amazing comparison sir.
    Thank You.

  5. amazing comparison sir.
    Thank You.

  6. I'm finding the comments more entertaining than the subject!
    Personally, I think thermometer manufacturers should consider other liquids/fluids for their thermometers; for instance: grape juice, guava/kiwi, or chocolate skim milk, let's say. Why? Think of how much fun it would be to keep on top of the weather, because you're thermometer is filled with type rH-negative, oxygenated blood! This would give you a new and novel experience in meteorology!

  7. This comment has been removed by the author.

  8. In disadvantage of mercury ,you have written that display is harder to read...but nowadays there is digital thermometer.So I think it is better to delete that point

  9. Two reasons for using mercury and alcohol in thermometer

  10. Great! But why mercury gives slow response while it can measure the temperatures quickly and precisely ?