How can you determine the lower and upper fixed point in the mercury thermometer?
The lower fixed point is determined by the temperature of pure melting ice and the upper fixed point is determined by temperature of pure boiling water.
What is a lower fixed point?
The lower fixed point, or ice point, is the temperature of pure melting ice at normal atmospheric pressure. The upper fixed point, or steam point, is the temperature of pure boiling water at normal atmospheric pressure.
What are the lower upper fixed point?
In the case of the Celsius scale, the lower point is the melting point of pure ice at normal atmospheric pressure and the upper fixed point is the boiling point of pure water at normal atmospheric pressure (1atm).
What is the lowest fixed point of laboratory thermometer?
The lower fixed point in a laboratory thermometer is the same as that of 10°C.
Why mercury is 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.
Which thermometer does not contain mercury?
Explanation: Digital thermometer – These thermometers do not use mercury and they have dedicated electronic circuits to measure temperature.
What are the fixed points in a thermometer?
Fixed points are used in calibrating thermometers. To calibrate a thermometer is to mark a thermometer so that you can use it to measure temperature accurately. A fixed point is a standard degree of hotness or coldness such as the melting point of ice or boiling point of water.
Do they sell mercury thermometers anymore?
What Will Replace Them? The National Institute of Standards and Technology (NIST) announced last week that it would stop calibrating mercury thermometers starting March 1 a move that brings the U.S. one step closer to phasing out these temperature-measuring devices for good.
Why is mercury not used in thermometers anymore?
The reason: Mercury released into the environment from a broken thermometer is highly poisonous. So government and state agencies have mounted campaigns to end the use of thermometers that contain the liquid metal. Federal and state authorities have lobbied since 2002 for bans on medical mercury thermometers.