Question

water cannot be used as a liquid in a thermometers. why ?????

Answer 1

thermometer uses a special liquid called Mercury. in laboratory thermometer and thermister is used in digital thermometer because these liquid had a power to show how cold or hot is the body that to measure fever water is a universal solvent but cannot had a property to measure temperature. so water is not used in thermometer also Mercury does not stick to glass

Answer 2

Mercury expands much more than water when heat is there.And mercury doesn't stick to the surface of glass like water and cause a wrong reading.But mercury has now been banned in thermometers and people have to use alcahol which has similar properties.