For a thermometer we need a liquid which properly expands and contracts according to the temprature. Water doesn't has that property, i.e. the expansion in water is to small to be used as a liquid in theremometer.
I would guess it is probably due to the fact that water has a none linear thermal expansion (Its thermal expansion coefficient at 20C is not the same as at 90C). Also, at atmospheric pressure, water is only liquidus over a narrow temperature range of 100C which limits its usefulness. Further it has massive problems at phase transitions- for instance when it turns to a gas it consumes a lot of energy (latent heat). A thermometer should have a nice linear response to a rise in temperature. Mercury is a better choice since it doesnt have any phase transitions in the temperature experience in most every day situations. -Just a bit toxic.
Mercury or Alcohol is used as it has a good steady linear thermal expansion over quite a large temperature range.
Water does not behave the same, and it freezes at 0 degrees (and gets larger, thus it would break the glass) and it boils at 100 celcius, so that isn't much use either.
Three reasons:
But water&alcohol thermometers are known, and much safer to use: Mercury is toxic when it comes free from broken Hg-thermometers.
because water is a normal liquid that they cannot measuring like temperature and because water has a oxygen that they can use in high measuring.
Mercury is used in thermometers. The mercury is the red substance in the thermometer that rises when you put it in your mouth.
The liquid commonly used in a thermometer is mercury or COLOURED ALCOHOL.
Alcoholic thermometers are more accurate than mercury thermometers
it is used in liquid form as in room temperature the mercury is in liquid
mercury
Alcohol, usually with a red dye in it
The first thermometer was a tube filled with water and air.
A mercury thermometer is used to measure temperature.
Mercury is used in thermometers. The mercury is the red substance in the thermometer that rises when you put it in your mouth.
The liquid commonly used in a thermometer is mercury or COLOURED ALCOHOL.
Mercury and alcohol
Water does not change as much in volume with temperature as much as Mercury does, which makes it more difficult to read temperature Changes on a scale.
A mercury thermometer can go down to -30 deg C
mercury
toxic poison
Mercury
Alcoholic thermometers are more accurate than mercury thermometers