Week 06 of 15 – Terms	Name: Answer Sheet

In your own words, write a definition for each of the following terms. Plagiarism will be checked and not tolerated.

Points: 5 pts/each = 11 * 5 = 55 pts

Fahrenheit

A temperature scale in which the freezing point of pure water occurs at 32°F and the span between the freezing point and boiling point of pure water at standard pressure is defined to be 180 scale divisions (180 degrees).

Rankine

An absolute temperature scale (abbreviation R) in which the zero point is defined as absolute zero (the point at which all spontaneous molecular motion ceases). The scale divisions in Rankine are equal to the scale divisions in the Fahrenheit system. Zero degrees Fahrenheit (0°F) equals approximately 459.69°R.

Celsius

A scale for measuring temperature that is based on the definition of 0°C and 100°C as the freezing point and boiling point, respectively, of pure water at standard pressure.

Kelvins

The metric unit for thermodynamic temperature. The Kelvin scale is an absolute temperature scale in which the zero point is defined as absolute zero (the point where all spontaneous molecular motion ceases). The scale divisions in Kelvin are equal to the scale divisions in the Celsius system. In the Kelvin system, the scale divisions are not referred to as “degrees” as they are on other temperature measurement systems. Rather, they are called kelvins. So, 0°C = approximately 273.16 kelvins (or K).

Bimetallic

1. Consisting of two metals, often bonded together and having different rates of thermal expansion. 2. Of, based on, or using the principles of bimetallism.

bimetallic. (n.d.) American Heritage® Dictionary of the English Language, Fifth Edition. (2011). Retrieved March 10 2016 fromhttp://www.thefreedictionary.com/bimetallic

As a thermometer element: A temperature-sensitive strip of metal (or other configuration) made by bonding or mechanically joining two dissimilar strips of metal together. Small changes in temperature will cause the composite assembly to distort elastically and produce a predictable deflection. The element is designed to take advantage of the fact that different metals have different coefficients of thermal expansion.

Thermocouple

1. A temperature-measuring instrument that develops an electric voltage when heated because of the combined thermoelectric effect caused by the dissimilar composition of two electrically connected conductors (usually wires) and by the temperature difference between the connection (hot junction) and the other end of the conductors (cold junction). 2. Two dissimilar wires joined together that generate a voltage that is proportional to temperature when their junction is heated.

Measuring junction

The electrical connection between the two legs of a thermocouple that is attached to the body or immersed in the medium whose temperature is to be measured. Also referred to as the hot junction.

Reference junction

1. That thermocouple junction which is at a known or reference temperature. The reference junction is physically that point at which the thermocouple or thermocouple extension wires are connected to a device or where the thermocouple is connected to a pair of (usually copper) lead wires. [ANSI/ISA-51.1-1979 (R1993)] 2. A device that is used with a thermocouple transducer, which couples the device to copper wires without introducing an error.

Seebeck effect

The development of a voltage as a result of the differences in temperature between two junctions of dissimilar metals in the same circuit.

Resistive Temperature Device (RTD)

1. A component of a resistance thermometer that consists of a material whose electrical resistance is a known function of temperature. 2. A temperature transducer that provides temperature information in the following form: as the change in resistance of a metal wire element, often platinum, as a function of temperature.

Thermistor

A temperature transducer that is constructed from semiconductor material, the resistance of which varies nonlinearly with temperature. Resistance usually decreases with increasing temperature. The usual applications of a thermistor are as a nonlinear circuit element (either alone or in combination with a heater), as a temperature compensator in a measurement circuit, or as a temperature-measurement element.