The thermometer is a device that measures temperature or temperature gradient using a variety of different principles; it comes from the Greek roots thermo, heat, and meter, to measure. A thermometer has two important elements: the temperature sensor (e.g. the bulb on a Mercury thermometer) in which some physical change occurs with temperature, plus some means of converting this physical change into a value (e.g. the scale on a mercury thermometer). Industrial thermometers commonly use electronic means to provide a digital display or input to a computer. Thermometers can be divided into two groups according to the level of knowledge about the physical basis of the underlying thermodynamic laws and quantities. For primary thermometersthe measured property of matter is known so well that temperature can be calculated without any unknown quantities. Examples of these are thermometers based on the equation of state of a gas, on the velocity of sound in a gas, on the thermal noise (see Johnson-Nyquist noise) voltage or current of an electrical resistor, and on the angular anisotropy of gamma ray emission of certain radioactive nuclei in a magnetic field. Secondary thermometers are most widely used because of their convenience. Also, they are often much more sensitive than primary ones. For secondary thermometers knowledge of the measured property is not sufficient to allow direct calculation of temperature. They have to be calibrated against a primary thermometer at least at one temperature or at a number of fixed temperatures. Such fixed points, for example, triple points and superconducting transitions, occur reproducibly at the same temperature. Internationally agreed temperature scales are based on fixed points and interpolating thermometers. The most recent official temperature scale is the International Temperature Scale of 1990. It extends from 0.65 K to approximately 1358 K (−272.5 °C to 1085 °C). qewbuor'/
to measure temperature.
Mercury.
Celsius.
Meow Mix and Vacuum cleaners
By using denser mercury instead of ethanol.
Thermometers are disinfected after each use to reduce the risk of infection.
by the metallic coeffeictent of expansion of mercury. When mercury gets warmer it "spreads out" (expands) when it cools it "shrinks".
Mercury. It isn't used much these days in thermometers these days as it is very toxic.
There were no thermometers in the medieval period. The earliest ones were developed around 1600 (well into the modern era of history).
K. Svanholm has written: 'Gamma thermometer and neutron detector application' -- subject(s): Neutron counters, Themometers and themometry
on the list
List is a noun (a list) and a verb (to list).