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Celsius
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For other uses, see Celsius (disambiguation).
A thermometer calibrated in degrees Celsius
The Celsius scale, previously known as the centigrade scale,[1][2] is an SI scale and unit of measurement for temperature. As an SI derived unit, it is used by all countries in the world, except the U.S. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval, a difference between two temperatures or an uncertainty. Before being renamed to honour Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps.
The Celsius scale was based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure following a change introduced in 1743 by Jean-Pierre Christin to reverse the Celsius thermometer scale (from water boiling at 0 degrees and ice melting at 100 degrees). This scale is widely taught in schools today. By international agreement the unit "degree Celsius" and the Celsius scale are currently defined by two different temperatures: absolute zero, and the triple point of Vienna Standard Mean Ocean Water (VSMOW), a specially purified water. This definition also precisely relates the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature with symbol K. Absolute zero, the lowest temperature possible, is defined as being exactly 0 K and −273.15 °C. The temperature of the triple point of water is defined as exactly 273.16 K (0.01 °C; 32.02 °F).[3]
Thus, a temperature difference of one degree Celsius and that of one kelvin are exactly the same, with the null point of the Kelvin scale (0 K) at exactly −273.15 °C, and the null point of the Celsius scale (0 °C) at exactly 273.15 K.[4]
Contents
[hide]
1 History
1.1 Centigrade, hectograde and Celsius
1.2 Common temperatures
2 Name and symbol typesetting
2.1 Unicode character
3 Temperatures and intervals
4 Coexistence of Kelvin and Celsius scales
5 Melting and boiling points of water
6 See also
7 Notes
8 References
9 External links
History[edit]
An illustration of Anders Celsius's original thermometer. Note the reversed scale, where 100 is the freezing point of water and 0 is its boiling point.
In 1742, Swedish astronomer Anders Celsius (1701–1744) created a temperature scale which was the reverse of the scale now known by the name "Celsius": 0 represented the boiling point of water, while 100 represented the freezing point of water.[5] In his paper Observations of two persistent degrees on a thermometer, he recounted his experiments showing that the melting point of ice is essentially unaffected by pressure. He also determined with remarkable precision how the boiling point of water varied as a function of atmospheric pressure. He proposed that the zero point of his temperature scale, being the boiling point, would be calibrated at the mean barometric pressure at mean sea level. This pressure is known as one standard atmosphere. The BIPM's 10th General Conference on Weights and Measures (CGPM) later defined one standard atmosphere to equal precisely 1013250dynes per square centimetre (101.325 kPa).[6]
In 1743, the Lyonnais physicist Jean-Pierre Christin, permanent secretary of the Académie des sciences, belles-lettres et arts de LyonFR, working independently of Celsius, developed a scale where zero represented the freezing point of water and 100 represented the boiling point of water.[7][8] On 19 May 1743 he published the design of a mercury thermometer, the "Thermometer of Lyon" built by the craftsman Pierre Casati that used this scale.[9][10][11]
In 1744, coincident with the death of Anders Celsius, the Swedish botanist Carolus Linnaeus (1707–1778) reversed Celsius's scale.[12] His custom-made "linnaeus-thermometer", for use in his greenhouses, was made by Daniel Ekström, Sweden's leading maker of scientific instruments at the time and whose workshop was located in the basement of the Stockholm observatory. As often happened in this age before modern communications, numerous physicists, scientists, and instrument makers are credited with having independently developed this same scale;[13] among them were Pehr Elvius, the secretary of the Royal Swedish Academy of Sciences (which had an instrument workshop) and with whom Linnaeus had been corresponding; Daniel Ekström[SV], the instrument maker; and Mårten Strömer (1707–1770) who had studied astronomy under Anders Celsius.
The first known Swedish document[14] reporting temperatures in this modern "forward" Celsius scale is the paper Hortus Upsaliensis dated 16 December 1745 that Linnaeus wrote to a student of his, Samuel Nauclér. In it, Linnaeus recounted the temperatures inside the orangery at the University of Uppsala Botanical Garden:
...since the caldarium (the hot part of the greenhouse) by the angle of the windows, merely from the rays of the sun, obtains such heat that the thermometer often reaches 30 degrees, although the keen gardener usually takes care not to let it rise to more than 20 to 25 degrees, and in winter not under 15 degrees...
Centigrade, hectograde and Celsius[edit]
Since the 19th century, the scientific and thermometry communities worldwide referred to this scale as the centigrade scale. Temperatures on the centigrade scale were often reported simply as degrees or, when greater specificity was desired, as degrees centigrade (symbol: °C). Because the term centigrade was also the Spanish and French language name for a unit of angular measurement (1/100 of a right angle) and had a similar connotation in other languages, the term centesimal degree (known as the gradian, "grad" or "gon": 1ᵍ = 0.9°, 100ᵍ = 90°) was used when very precise, unambiguous language was required by international standards bodies such as the BIPM. More properly, what was defined as "centigrade" then would now be "hectograde". Furthermore, in the context here, centigrade/hectograde is referring to the whole 0–100 range, not the given part thereof, hence "20° centigrade" means "20ᵍ per 100 gradians" (or 20% hectograde), not its literal description, "0.2 gradians".
(To be descriptively correct, "20° centigrade" should be "20° hectocentigrade", or just "20 gradians" {20ᵍ}.)
To eliminate such confusion, the 9th CGPM and the CIPM (Comité international des poids et mesures) formally adopted "degree Celsius" in 1948,[15][a] formally keeping the recognized degree symbol, rather than adopting the gradian/centesimal degree symbol.
For scientific use, "Celsius" is the term usually used, with "centigrade" otherwise continuing to be in common but decreasing use, especially in informal contexts in English-speaking countries.[16] It was not until February 1985 that the forecasts issued by the BBC switched from "centigrade" to "Celsius".[17]
Common temperatures[edit]
Some key temperatures relating the Celsius scale to other temperature scales are shown in the table below.
Key scale relations
Kelvin
Celsius
Fahrenheit
Absolute zero
(precisely, by definition) 0 K −273.15 °C −459.67 °F
Boiling point of liquid nitrogen 77.4 K −195.8 °C[18] −320.4 °F
Sublimation point of dry ice. 195.1 K −78 °C −108.4 °F
Intersection of Celsius and Fahrenheit scales. 233.15 K −40 °C −40 °F
Melting point of H2O (purified ice)[19] 273.1499 K −0.0001 °C 31.9998 °F
Water's triple point
(precisely, by definition) 273.16 K 0.01 °C 32.018 °F
Normal human body temperature (approximate average)[20] 310.15 K 37.0 °C 98.6 °F
Water's boiling point at 1 atm (101.325 kPa)
(approximate: see Boiling point)[b] 373.1339 K 99.9839 °C 211.971 °F
Name and symbol typesetting[edit]
The "degree Celsius" has been the only SI unit whose full unit name contains an uppercase letter since the SI base unit for temperature, the kelvin, became the proper name in 1967 replacing the term degrees Kelvin. The plural form is degrees Celsius.[21]
The general rule of the International Bureau of Weights and Measures (BIPM) is that the numerical value always precedes the unit, and a space is always used to separate the unit from the number, e.g. "30.2 °C" (not "30.2°C" or "30.2° C").[22] Thus the value of the quantity is the product of the number and the unit, the space being regarded as a multiplication sign (just as a space between units implies multiplication). The only exceptions to this rule are for the unit symbols for degree, minute, and second for plane angle (°, ′, and ″, respectively), for which no space is left between the numerical value and the unit symbol.[23] Other languages, and various publishing houses, may follow different typographical rules.
Unicode character[edit]
Unicode provides the Celsius symbol at codepoint U+2103 ℃ degree celsius. However, this is a compatibility character provided for roundtrip compatibility with legacy encodings. It easily allows correct rendering for vertically written East Asian scripts, such as Chinese. The Unicode standard explicitly discourages the use of this character: "In normal use, it is better to represent degrees Celsius "°C" with a sequence of U+00B0 ° degree sign + U+0043 C latin capital letter c, rather than U+2103 ℃ degree celsius. For searching, treat these two sequences as identical."[24]
Shown below is the degree Celsius character followed immediately by the two-component version:
℃ °C
When viewed on computers that properly support Unicode, the above line may be similar to the image in the line below (enlarged for clarity):
The canonical decomposition is simply an ordinary degree sign and "C", so some browsers may simply display "°C" in its place due to Unicode normalization.
Temperatures and intervals[edit]
The degree Celsius is a special name for the kelvin for use in expressing Celsius temperatures.[25] The degree Celsius is also subject to the same rules as the kelvin with regard to the use of its unit name and symbol. Thus, besides expressing specific temperatures along its scale (e.g. "Gallium melts at 29.7646 °C" and "The temperature outside is 23 degrees Celsius"), the degree Celsius is also suitable for expressing temperature intervals: differences between temperatures or their uncertainties (e.g. "The output of the heat exchanger is hotter by 40 degrees Celsius", and "Our standard uncertainty is ±3 °C").[26] Because of this dual usage, one must not rely upon the unit name or its symbol to denote that a quantity is a temperature interval; it must be unambiguous through context or explicit statement that the quantity is an interval.[c] This is sometimes solved by using the symbol °C (pronounced "degrees Celsius") for a temperature, and C° (pronounced "Celsius degrees") for a temperature interval, although this usage is non-standard.[27]
What is often confusing about the Celsius measurement is that it follows an interval system but not a ratio system; that it follows a relative scale not an absolute scale. This is put simply by illustrating that while 10 °C and 20 °C have the same interval difference as 20 °C and 30 °C the temperature 20 °C is not twice the air heat energy as 10 °C. As this example shows, degrees Celsius is a useful interval measurement but does not possess the characteristics of ratio measures like weight or distance.[28]
Coexistence of Kelvin and Celsius scales[edit]
In science and in engineering, the Celsius scale and the Kelvin scale are often used in combination in close contexts, e.g. "...a measured value was 0.01023 °C with an uncertainty of 70 µK...". This practice is permissible because the magnitude of the degree Celsius is equal to that of the kelvin, but referring to a "microdegree Celsius" would be awkward.
Notwithstanding the official endorsement provided by decision #3 of Resolution 3 of the 13th CGPM, which stated "a temperature interval may also be expressed in degrees Celsius", the practice of simultaneously using both °C and K remains widespread throughout the scientific world as the use of SI-prefixed forms of the degree Celsius (such as "µ°C" or "microdegrees Celsius") to express a temperature interval has not been well-adopted.
Melting and boiling points of water[edit]
One effect of defining the Celsius scale at the triple point of Vienna Standard Mean Ocean Water (VSMOW, 273.16 K and 0.01 °C), and at absolute zero (0 K and −273.15 °C), is that neither the melting nor boiling point of water under one standard atmosphere (101.325 kPa) remains a defining point for the Celsius scale. In 1948 when the 9th General Conference on Weights and Measures (CGPM) in Resolution 3 first considered using the triple point of water as a defining point, the triple point was so close to being 0.01 °C greater than water's known melting point, it was simply defined as precisely 0.01 °C.[29] However, current measurements show that the difference between the triple and melting points of VSMOW is actually very slightly (<0.001 °C) greater than 0.01 °C. Thus, the actual melting point of ice is very slightly (less than a thousandth of a degree) below 0 °C. Also, defining water's triple point at 273.16 K precisely defined the magnitude of each 1 °C increment in terms of the absolute thermodynamic temperature scale (referencing absolute zero). Now decoupled from the actual boiling point of water, the value "100 °C" is hotter than 0 °C – in absolute terms – by a factor of precisely 373.15/273.15 (approximately 36.61% thermodynamically hotter). When adhering strictly to the two-point definition for calibration, the boiling point of VSMOW under one standard atmosphere of pressure is actually 373.1339 K (99.9839 °C). When calibrated to ITS-90 (a calibration standard comprising many definition points and commonly used for high-precision instrumentation), the boiling point of VSMOW is slightly less, about 99.974 °C.[30]
This boiling-point difference of 16.1 millikelvin between the Celsius scale's original definition and the current one (based on absolute zero and the triple point) has little practical meaning in common daily applications because water's boiling point is very sensitive to variations in barometric pressure. For example, an altitude change of only 28 cm (11 in) causes the boiling point to change by one millikelvin.
Celsius temperature conversion formulae
from Celsius
to Celsius
Fahrenheit
[°F] = [°C] × 9⁄5 + 32 [°C] = ([°F] − 32) × 5⁄9
Kelvin
[K] = [°C] + 273.15 [°C] = [K] − 273.15
Rankine
[°R] = ([°C] + 273.15) × 9⁄5 [°C] = ([°R] − 491.67) × 5⁄9
For temperature intervals rather than specific temperatures,
1 °C = 1 K = 9⁄5 °F = 9⁄5 °R
Comparisons among various temperature scales
See also[edit]
Comparison of temperature scales
Degrees of frost
ITS-90
Réaumur scale
Thermodynamic temperature
Notes[edit]
Jump up ^ According to The Oxford English Dictionary (OED), the term "Celsius' thermometer" had been used at least as early as 1797. Further, the term "The Celsius or Centigrade thermometer" was again used in reference to a particular type of thermometer at least as early as 1850. The OED also cites this 1928 reporting of a temperature: "My altitude was about 5,800 metres, the temperature was 28° Celsius." However, dictionaries seek to find the earliest use of a word or term and are not a useful resource as regards to the terminology used throughout the history of science. According to several writings of Dr. Terry Quinn CBE FRS, Director of the BIPM (1988–2004), including "Temperature Scales from the early days of thermometry to the 21st century" (PDF). (146 KiB) as well as Temperature (2nd Edition/1990/Academic Press/0125696817), the term Celsius in connection with the centigrade scale was not used whatsoever by the scientific or thermometry communities until after the CIPM and CGPM adopted the term in 1948. The BIPM was not even aware that "degree Celsius" was in sporadic, non-scientific use before that time. It is also noteworthy that the twelve-volume, 1933 edition of OED didn't even have a listing for the word Celsius (but did have listings for both centigrade and centesimal in the context of temperature measurement). The 1948 adoption of Celsius accomplished three objectives:
1. All common temperature scales would have their units named after someone closely associated with them; namely, Kelvin, Celsius, Fahrenheit, Réaumur and Rankine.
2. Notwithstanding the important contribution of Linnaeus who gave the Celsius scale its modern form, Celsius' name was the obvious choice because it began with the letter C. Thus, the symbol °C that for centuries had been used in association with the name centigrade could continue to be used and would simultaneously inherit an intuitive association with the new name.
3. The new name eliminated the ambiguity of the term "centigrade", freeing it to refer exclusively to the French-language name for the unit of angular measurement.
Jump up ^ For Vienna Standard Mean Ocean Water at one standard atmosphere (101.325 kPa) when calibrated solely per the two-point definition of thermodynamic temperature. Older definitions of the Celsius scale once defined the boiling point of water under one standard atmosphere as being precisely 100 °C. However, the current definition results in a boiling point that is actually 16.1 mK less. For more about the actual boiling point of water, see VSMOW in temperature measurement. There is a different approximation using ITS-90 which approximates the temperature to 99.974 °C
Jump up ^ In 1948, Resolution 7 of the 9th CGPM stated, "To indicate a temperature interval or difference, rather than a temperature, the word 'degree' in full, or the abbreviation 'deg' must be used." This resolution was abrogated in 1967/1968 by Resolution 3 of the 13th CGPM which stated that ["The names "degree Kelvin" and "degree", the symbols "°K" and "deg" and the rules for their use given in Resolution 7 of the 9th CGPM (1948),] ...and the designation of the unit to express an interval or a difference of temperatures are abrogated, but the usages which derive from these decisions remain permissible for the time being." Consequently, there is now wide freedom in usage regarding how to indicate a temperature interval. The most important thing is that one's intention must be clear and the basic rule of the SI must be followed; namely that the unit name or its symbol must not be relied upon to indicate the nature of the quantity. Thus, if a temperature interval is, say, 10 K or 10 °C (which may be written 10 kelvin or 10 degrees Celsius), it must be unambiguous through obvious context or explicit statement that the quantity is an interval. Rules governing the expressing of temperatures and intervals are covered in the BIPM's "SI Brochure, 8th edition" (PDF). (1.39 MiB).
References[edit]
Jump up ^ "Celsius temperature scale". Encyclopædia Britannica. Retrieved 19 February 2012. Celsius temperature scale, also called centigrade temperature scale, scale based on 0° for the freezing point of water and 100° for the boiling point of water at 1 atm pressure.
Jump up ^ Helmenstine, Anne Marie (December 15, 2014). "What Is the Difference Between Celsius and Centigrade?". Chemistry.about.com. About.com. Retrieved March 16, 2015.
Jump up ^ "SI brochure, section 2.1.1.5". International Bureau of Weights and Measures. Archived from the original on 26 September 2007. Retrieved 9 May 2008.
Jump up ^ "Essentials of the SI: Base & derived units". Retrieved 9 May 2008.
Jump up ^ Celsius, Anders (1742) "Observationer om twänne beständiga grader på en thermometer" (Observations about two stable degrees on a thermometer), Kungliga Svenska Vetenskapsakademiens Handlingar (Proceedings of the Royal Swedish Academy of Sciences), 3 : 171–180 and Fig. 1.
Jump up ^ "Resolution 4 of the 10th meeting of the CGPM (1954)".
Jump up ^ Don Rittner; Ronald A. Bailey (2005): Encyclopedia of Chemistry. Facts On File, Manhattan, New York City. pp. 43.
Jump up ^ Smith, Jacqueline (2009). "Appendix I: Chronology". The Facts on File Dictionary of Weather and Climate. Infobase Publishing. p. 246. ISBN 978-1-4381-0951-0. 1743 Jean-Pierre Christin inverts the fixed points on Celsius' scale, to produce the scale used today.
Jump up ^ Mercure de France (1743): MEMOIRE sur la dilatation du Mercure dans le Thermométre. Chaubert; Jean de Nully, Pissot, Duchesne, Paris. pp. 1609–1610.
Jump up ^ Journal helvétique (1743): LION. Imprimerie des Journalistes, Neuchâtel. pp. 308–310.
Jump up ^ Memoires pour L'Histoire des Sciences et des Beaux Arts (1743): DE LYON. Chaubert, París. pp. 2125–2128.
Jump up ^ Citation: Uppsala University (Sweden), Linnaeus' thermometer
Jump up ^ Citation for Daniel Ekström, Mårten Strömer, Christin of Lyons: The Physics Hypertextbook, Temperature; citation for Christin of Lyons: Le Moyne College, Glossary, (Celsius scale); citation for Linnaeus' connection with Pehr Elvius and Daniel Ekström: Uppsala University (Sweden), Linnaeus' thermometer; general citation: The Uppsala Astronomical Observatory, History of the Celsius temperature scale
Jump up ^ Citations: University of Wisconsin–Madison, Linnæus & his Garden and; Uppsala University, Linnaeus' thermometer
Jump up ^ "CIPM, 1948 and 9th CGPM, 1948". International Bureau of Weights and Measures. Retrieved 9 May 2008.
Jump up ^ "centigrade, adj. and n". Oxford English Dictionary. Oxford University Press. Retrieved 20 November 2011.
Jump up ^ 1985 BBC Special: A Change In The Weather on YouTube
Jump up ^ Lide, D.R., ed. (1990–1991). Handbook of Chemistry and Physics. 71st ed. CRC Press. p. 4–22.
Jump up ^ The ice point of purified water has been measured to be 6995890000000000000♠0.000089(10) degrees Celsius – see Magnum, B.W. (June 1995). "Reproducibility of the Temperature of the Ice Point in Routine Measurements" (PDF). Nist Technical Note. 1411. Archived from the original (PDF) on July 14, 2007. Retrieved 11 February 2007.
Jump up ^ Elert, Glenn (2005). "Temperature of a Healthy Human (Body Temperature)". The Physics Factbook. Retrieved 22 August 2007.
Jump up ^ "Unit of thermodynamic temperature (kelvin)". The NIST Reference on Constants, Units, and Uncertainty: Historical context of the SI. National Institute of Standards and Technology (NIST). 2000. Retrieved 16 November 2011.
Jump up ^ BIPM, SI Brochure, Section 5.3.3.
Jump up ^ For more information on conventions used in technical writing, see the informative SI Unit rules and style conventions by the NIST as well as the BIPM's SI brochure: Subsection 5.3.3, Formatting the value of a quantity.
Jump up ^ "22.2". The Unicode Standard, Version 9.0 (PDF). Mountain View, CA, USA: The Unicode Consortium. July 2016. ISBN 978-1-936213-13-9. Retrieved 20 April 2017.
Jump up ^ Note (e) of SI Brochure, Section, 2.2.2, Table 3
Jump up ^ Decision #3 of Resolution 3 of the 13th CGPM
Jump up ^ H.D. Young, R.A. Freedman (2008). University Physics with Modern Physics (12th ed.). Addison Wesley. p. 573
Jump up ^ This fact is demonstrated in the book Biostatistics: A Guide to Design, Analysis, and Discovery By Ronald N. Forthofer, Eun Sul Lee and Mike Hernandez
Jump up ^ "Resolution 3 of the 9th CGPM (1948)". International Bureau of Weights and Measures. Retrieved 9 May 2008.
Jump up ^ Citation: London South Bank University, Water Structure and Behavior, notes c1 and c2
External links[edit]
Look up Celsius in Wiktionary, the free dictionary.
NIST, Basic unit definitions: Kelvin
The Uppsala Astronomical Observatory, History of the Celsius temperature scale
London South Bank University, Water, scientific data
BIPM, SI brochure, section 2.1.1.5, Unit of thermodynamic temperature
TAMPILE, Comparison of temperature scales
C to F converter, Celsius to Fahrenheit Converter
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text:
Welfare definition of economics
From Wikipedia, the free encyclopedia
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The welfare definition of economics is an attempt by Alfred Marshall, a pioneer neoclassical economist, to redefine his field of study. This definition expands the field of economic science to a larger study of humanity. Specifically, Marshall's view is that economics studies all the actions that people take in order to achieve economic welfare. In the words of Marshall, "man earns money to get material welfare." This is why economists since Marshall have described his definition as the welfare definition of economics. This definition enlarged the scope of economic science by emphasizing the study of wealth and humanity together, rather than wealth alone.
In his widely read textbook, Principles of Economics, published in 1890, Marshall defines economics as follow
"Political Economy or Economics is a study of mankind in the ordinary business of life; it examines that part of individual and social action which is most closely connected with the attainment and with the use of material requisites of well-being".[1]
Contents
[hide]
1 Implications
2 Impact on economics
3 Criticism
4 Economic welfare
5 References
6 See also
Implications[edit]
The following are the implications of this definition:
Economics is a study of humankind.
Human life has several aspects: social, religious, economic and political—but economics is concerned only with the economic aspect of life.
Promotion of welfare is the ultimate goal, but the term welfare is used in a narrow sense to meet material welfare only.[2]
According to Edwin Cannan, "the aim of political economy or Economics is the explanation of the general causes on which the material welfare of human beings depend".
Marshall clearly explains that economic activity is different from other activity. For example,
If a student visits a friend who is ill, it is a social activity,
If a person give his vote in an election, it is a political activity.
If a person goes to church/temple it is a religious activity.[3]
Marshall defines economic activity as separate from the above activities. A farmer who toils in the field, or a worker on an assembly, are performing an economic activity: they work to increase their material welfare (primarily by earning money). Money buys goods or services that satisfy wants. In other words, economics deals with effort, wants, and the satisfaction of those wants.
Impact on economics[edit]
Followers in the neoclassical tradition, such as William Beveridge and Arthur Pigou have continued to define economics in terms of material economic welfare. According to Pigou, "the range of enquiry becomes restricted to that part of social welfare that can be brought directly or indirectly into relation with the measuring rod of money".[4]
Criticism[edit]
Marshall’s definition has been criticized by more recent economists, including Lionel Robbins. Robbins' criticisms include:
(1) Narrows down the scope of economics. Marshall distinguishes between material and non-material welfare, and confines economics to the study of material welfare. Robbins feels that economists should not limit their attention to material welfare. There are things that are "non-material" but they promote human welfare. Robbins cites “the services of doctors, lawyers, teachers, dancers, engineers, professors". These goods "satisfy our wants and are scarce in supply”.[5] Some economists feel that Marshall's definition of "material" includes both goods and services, and that Robbins is either misreading Marshall's text, or creating a straw man argument.[6]
(2) Assumes equivalency between welfare and economic activity. For Robbins, there are economic activities which do not promote human welfare. For example, the sale of cocaine or heroin. Here Robbins says, “Why talk of welfare at all? Why not throw away the mask altogether”.
(3) It is a vague concept. According to Robbins, “welfare” is a vague concept to use to define economics because it is subjective. Economics is a quantitative science; but welfare cannot be quantitatively measured, and two persons cannot agree on what creates or improves welfare.
(4) It involves value judgement. Finally the word “welfare” in Marshall’s definition brings economics to the realm of ethics. Robbins would prefer that economics remain neutral in assessing the results of economic transactions.
Economic welfare[edit]
Broadly, economic welfare is the level of prosperity and standard of living of either an individual or a group of persons. In the field of economics, it specifically refers to utility gained through the achievement of material goods and services. In other words, it refers to that part of social welfare that can be fulfilled through economic activity.[7]
According to Roefie Hueting, welfare is dependent on factors like employment, income distribution, labor conditions, leisure time, production and the scarce possible uses of the environmental functions.[8]
Economic welfare is measured in different ways, depending on the preferences of those measuring it. Factors used to measure the economic welfare of a population, include: GDP, literacy, access to health care, and assessments of environmental quality.
References[edit]
Jump up ^ Marshall, Alfred (1890). "Principles of Economics". Retrieved October 26, 2011.
Jump up ^ Buchanan, James M. (1987). "opportunity cost", The New Palgrave: A Dictionary of Economics, v. 3, pp. 718–21.
Jump up ^ Robbins, Lionel (1934). Economics as a Science Of Scarcity and Choice. MacMillan.
Jump up ^ Pigou, Arthur C. (1920). The Economics of Welfare. MacMillan. Chapter 1, Section 1.
Jump up ^ “Nature and Significance of Economics Science”
Jump up ^ Friedman Milton (1953). "The Methodology of Positive Economics", Essays in Positive Economics, University of Chicago Press, p. 71.
Jump up ^ Samuelson, Paul A.; William D. Nordhaus (2004). Economics. McGraw-Hill.
Jump up ^ Hueting, R. (2011): The future of the Environmentally sustainable national income. Ökologisches Wirtschaften, 4/2011, 30-35
See also[edit]
Utility
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text:
A (Pretty Little Liars)
From Wikipedia, the free encyclopedia
Jump to: navigation, search
“A”
Pretty Little Liars character
First appearance
Novel:
Pretty Little Liars (2006)
Television:
"Pilot" (episode 1.01)[1]
Created by
Sara Shepard
Information
Aliases
Original A
Big A
Uber A
A-moji
A.D.
Pathology
Stalker
Spy
Blackmailer
Torturer
Manipulator
M.O.
Spying targets to discover secrets, taunting and threatening their victims via phone
Location
Rosewood, Pennsylvania
"A" is a fictional character created in 2006 by author Sara Shepard. It is a character of both Pretty Little Liars' books and television series, and primarily appears as a stalker and the main antagonist of the stories. "A" is one of the main characters of the stories, appearing anonymously in the majority of the episodes and books.
The villain has already had many portrayals. Its basic occupation is to pursue and threaten the four protagonists of the stories. Thus, many identities have been revealed to be "A". "A" has a specific and unhealthy way of dealing with the protagonists; it often calls them as "bitches", "dolls" and "liars". Its handling and acts of terrorism caused great psychological and emotional damage to the protagonists, even leading them to be hospitalized.
After the revelation of Mona Vanderwaal as the first and original "A", she began receiving visits from someone, known as Red Coat, who offered her a partnership and together they built up the "A-Team". The team had many members but disbanded after the season three finale and Big A began working with a single ally. The identity of the second "A", Red Coat, and the leader of the "A-Team" was revealed to be CeCe Drake, while her ally that donned the Black Widow and other Red Coat disguise was revealed to be Sara Harvey. Five years later, a new mysterious entity arises and begins using Emojis to communicate but later baptizes themselves as "A.D.", while the Liars refer to the anonymous figure as Uber A. Then, in the Series Finale, "A.D." reveals themselves to be Alex Drake, the twin sister of Spencer.
Contents
[hide]
1 Development
1.1 Characterization
2 Novels storylines
2.1 The first "A"
2.2 The second "A"
2.2.1 The Helper, or Third "A"
3 Television storylines
3.1 Original "A"
3.2 Big "A"
3.3 Uber "A"
4 The A-Team
4.1 Members
4.1.1 Sara Harvey
4.1.2 Sydney Driscoll
4.1.3 Toby Cavanaugh
4.1.4 Spencer Hastings
4.1.5 Lucas Gottesman
4.1.6 Melissa Hastings
4.1.7 Darren Wilden
4.1.8 Jenna Marshall
4.1.9 Noel Kahn
4.1.10 Aria Montgomery
4.1.11 Mary Drake
4.1.12 Wren Kingston
5 Other "A's"
5.1 Caleb Rivers
5.2 Shana Fring
6 Disguises
6.1 Red Coat
6.2 The Black Widow
6.3 The Queen of Hearts
6.4 The Black Swan
6.5 The Black Hoodie
7 References
Development[edit]
Characterization[edit]
"A" makes appearances as a figure with black leather gloves, a black hood, dark pants, and dark shoes. Throughout the seasons, the story focuses on the mystery of "A". However, "Big A" also sported different disguises, including that of Red Coat, while their ally disguised themselves as The Black Widow, while also donning the Red Coat identity on certain occasions.
Uber A also dressed up as several disguises, including those of a gardener, a maid and a surgeon. They later costume themselves with the traditional look.
Novels storylines[edit]
The first "A"[edit]
Real identity: Mona Vanderwaal.
Three year after the disappearance of Alison DiLaurentis, her four friends, Aria Montgomery, Spencer Hastings, Emily Fields, and Hanna Marin, each receive messages from someone calling themselves "A." The girls had drifted apart over the years, so they had no idea that other people were getting texts as well. Additionally, the texts were about secrets only Ali knew about. At first, the messages were simply teasing and all of the girls wonder if their missing friend was the one who sent them. Though they knew she was most likely dead, she was still the only one who knew their darkest secrets. Once Ali's body is discovered in her old backyard, the girls are even more baffled when they continue to receive threats. At Ali's funeral, the girls are reunited and they find out that they've all been receiving weird messages. As the girls stand outside after the funeral ends, they all get a text saying, "I'm still here, bitches. And I know everything. —A".
From that point on, the messages take on a distinctly more threatening tone. Aria is given an ultimatum to tell her mother about her father's affair by midnight after the Foxy event, or A will do it for her. A continues to play life-altering games with the girls, from encouraging suspicion of Spencer's involvement in Ali's death to outing Emily's sexuality to her conservative mother. However, A makes a serious mistake in texting Hanna on the night of Mona's birthday party. Instead of using the plain Blackberry she bought just for tormenting the girls, A accidentally uses his/her own phone. Hanna, who has a new phone without all of her contacts recognizes the number, compelling A to act before Hanna can reveal A's true identity to the others. A hits Hanna with an SUV, successfully destroying Hanna's phone and putting her into a coma that eventually leads to a temporary loss of memory. Soon after that, "A" puts a drug in Emily's pain cream which causes an Ulcer in the spot where she has been putting the cream. She ends up in the hospital and might not be able to swim again.
A knew that there was a very good chance Hanna would regain her memory. Hanna's best friend, Mona Vanderwaal, informs the girls that she has also received texts from A, drawing the five closer together in trying to figure out who their tormentor is. Mona subtly encourages Spencer's fears that her sister, Melissa, might be A as well as Alison's killer. During Hanna's recovery masquerade celebration, she suddenly regains her memory, revealing that Mona is A. However, she, Emily, and Aria can't do much about it, because Spencer and Mona are on their way to the police station. After Spencer is warned about Mona by text, she tries to escape Mona's car, but Mona catches on rather quickly and diverts to a path in a more remote area of Rosewood. She tells Spencer everything, from seeing Ali launch a firework into Toby Cavanaugh's garage and blind her friend Jenna, to finding Ali's diary of secrets among a pile of old DiLaurentis junk the St. Germains left at the curb, discovering the girls' secrets that only Ali knew. Her motivation was to get revenge for her friend's blindness, even though Jenna and Ali had planned together to launch the firework. Mona didn't know this and got a scar on her stomach from the ordeal. Mona also drops the bombshell that Ian Thomas killed Ali, due to Ali's last diary entry about giving him an ultimatum to break up with Melissa. She then offers Spencer to become A with her and tell Hanna that she must not be remembering correctly, but she refuses. The two fight at Floating Man's Quarry and Spencer accidentally pushes Mona, who falls and has her neck caught between rocks.
The second "A"[edit]
Real identity: Alison DiLaurentis
As the girls move into the big red house they are shocked to receive messages from a new person claiming to be Alison. At first, they believe it's just a prank, especially since the first "A" got major news time. Then the girls believe it's Ian Thomas, who is the prime suspect of the investigation. Spencer is especially certain of this until finding Ian's body in the woods bordering her estate and the old DiLaurentis home. The girls all get a message from "A," saying "He had to go. -A".
However, this Alison is even more twisted than the first; Ian's body disappears and the town is largely convinced that it was a hoax. "A" even teases Spencer, stating, "Just because I said Ian had to go, it didn't mean he had to die." "A" pretends to be Ian, using an IM screenname of USCMidfielderRoxx, a testament to his alma mater and his love for field hockey. Through this new fake identity, "A" feeds Spencer some interesting information about her family, specifically her father's affair with Mrs. DiLaurentis and the possibility that Ali is her half sister. "A" proceeds to torment the girls even more: they force Spencer to focus more on her father's secret by enabling Spencer's surrogate mother to scam her and clear out her two million dollar trust fund. "A" taunts Aria with pictures of her and her mother's new love interest in compromising situations. They threaten to send these to her mother, even though Aria has tried to ward off her mother's new boyfriend. "A" lands Hanna in the Preserve at Addison-Stevens, a lush clinic for troubled patients. "A" sends Emily on a trip to the Amish community in Lancaster to dig up more dirt on Officer Wilden.
Throughout the second half of the series, the second "A" keeps up this forced information search with the girls, pushing them to find more information on Wilden and Jason DiLaurentis. "A" even plants the idea that they killed Ali. However, when Jenna is found dead in Heartless, "A" plants all of their texts, pictures, etc. on a random lecherous construction worker. This is one of the same workers who was involved in building the DiLaurentises' gazebo when "Alison" was still alive. The girls believe it is all over now, though the fact that the suspect is such a random person bothers them.
Everyone in Rosewood is shocked when the DiLaurentis's introduce the existence of a third child, Courtney DiLaurentis. She is the twin of Alison and was kept in various clinics because she was "ill". However, "Courtney" is actually Alison DiLaurentis herself. She reveals her true identity to each of the girls, hoping to gain their friendship and telling them she never died the night of the sleepover. She claims that Courtney must have gotten out of the house and ran into the construction worker, who killed her. Though the girls believe her and are glad to have their friend back, Aria is the most suspicious of her. It was recently discovered that Courtney liked to pretend to be Ali and she wasn't completely buying her story. Additionally, Wilden and Melissa are also suspicious of "Courtney". Melissa knew about the twins since high school, as their brother Jason confided in her. He told her they hated each other, but Spencer tells her about "Courtney's" statements that she and Ali shared everything together."
Ali's time is running out, for besides the few people suspicious of her, the police start to say that the construction worker has an alibi and might not be guilty. Her secret is further endangered when Aria finds and sends in a photo of a reflection of someone spying on the girls during the sleepover. The reflection is too blurry, but it is clearly a female. Ali takes Mona's idea and convinces Spencer that Melissa is the culprit. Meanwhile, she kidnaps Melissa- who has just figured out the truth- and keeps her in her family's Poconos home. She stuffs Melissa in a closet with Ian's corpse.
On the night of the school's Valentine dance, Ali convinces the girls to hang out with her at the Poconos home. They ditch the party and get wasted at her home. She asks them if she could reenact the night of the sleepover and hypnotize them. Everyone reluctantly agrees, and minutes later they wake up to find Ali gone and the door of the room locked. A letter is slid underneath, informing the girls of the horrible truth: The Alison that they had been friends with had been Courtney all along and the real Ali killed her.
Courtney was mentally unsound and wanted to be Ali so badly that she tried to drown her when they were children. One day, when she was home from the mental institute, Courtney stole Ali's ring and imitated her when she saw Spencer and the others sneaking into their backyard. Ali was sent to the new mental institute, the Preserve, in Courtney's place, and was forced to take her sister's messed up life. On the night of the sleepover, she spied on the girls, followed Courtney after her fight with Spencer, and killed her in revenge for taking her perfect life. She hates the girls for ruining her life and tries to kill them too by boarding up the entire home and setting it on fire. The girls, including Melissa, manage to escape, but no one knows whether Ali is alive. It's hinted that she might be, as Emily hears a faint giggle in the distance as she visits Courtney's grave in the evening.
The Helper, or Third "A"[edit]
By the end of Crushed, the Liars know that the Second "A", Alison, has had an accomplice the whole time, and that this accomplice is the Third "A". They believe that Alison did indeed survive the fire in the Poconos house, and thus that the Second and Third "A" are currently operating together to bring them down (and eventually kill them). The helper later is revealed to be Nick Maxwell, Alison's boyfriend when she was hospitalized. Nick was caught by the police when he and Alison planned to kill the Liars via poisoning. However, months later, the Liars visit Nick in the prison in order to discover some clues about Alison's whereabouts, and he gives them some information.
Television storylines[edit]
Original "A"[edit]
Mona Vanderwaal as "A."
Original A was the first "A" and revealed to be Mona Vanderwaal. Mona began torturing Alison by sending her gifts, threats and soon attacking her while wearing a zombie costume. "A" continued to mess with Ali and her mother Jessica DiLaurentis, whom she believed it to be Spencer Hastings. After Alison's disappearance, "A" went away for a year but after the corpse of Bethany Young (believed to be Alison at the time) was found, she reemerged. "A" began sending the Liars messages about things only Alison knew about them and soon even began messing with their parents. Doctor Anne Sullivan had previously dealt with the person behind the hoodie and when "A" trashed her office she immediately recognized the person. She almost exposes her identity to the Liars but "A" kidnaps her and went as far as to threaten her son's life. But the Liars are still close to figuring it out and during the second half of season two they manage to get a hold of "A's" phone. They hatch a plan to catch her with this and it works. They find out that "A" had a lair at the Lost woods resort and Spencer and Mona ("A's" newest victim) head over there and find a room full of pictures of Alison and the girls along with a sketch of "A's" costume to the ball, The Black Swan. However, Spencer begins to notice other clues and soon realizes "A" is right there with her. She turns around to see Mona in a black hoodie, who reveals herself as "A". She kidnaps Spencer and gives her an opportunity to join the "A" team but Spencer declines and the two get into a fight, where Mona is pushed off of a cliff. Though Mona survives, she is sent to Radley Sanitarium for medical assistance. While in the psychiatric hospital, Mona takes up a partnership suggested by the then unknown CeCe Drake that starts off the second game. After this, Mona became another henchmen in the "A" hierarchy, obeying the orders of CeCe, whom she knew as Red Coat. Mona was kicked off of the A-Team in the season three finale. However, Mona joins the new "A.D." team in Season 7, after "A.D." sends Wren to kill her and she offers to help instead. She helps them kidnap Spencer and wears a Melissa mask, but ultimately turns on them and brings the Liars to them, as well as a cop. However, this turns out to be a ruse and the "cop" is actually Mona's French boyfriend, who helps her take Mary and Alex (the two remaining members) to France to live in her own personal Dollhouse. Mona is the final "A" of the series, being the "winner" of the game.
Big "A"[edit]
CeCe Drake as "A".
Big A was the person who took over the "A" game from Mona Vanderwaal after she was admitted to Radley Sanitarium and revealed to be CeCe Drake. She had visited Mona in Radley and used her to get information about the Liars before taking over the game herself and had used Mona, Toby and Spencer to do her dirty work and sometimes went under the Red Coat disguise. Big A often hid out at a lair situated in Room A at an apartment building at Mayflower Hill and a mobile RV which was stolen but Toby gave it back to "A" in exchange for information about his mother's death. However, the Team was disbanded in the third-season finale and CeCe acted on her own with a few minions and an ally, who is Sara Harvey. It is revealed that Charlotte had been hiding out in the basement of the DiLaurentis house and drilled holes through the floor to spy on the family in her Red Coat disguise and shared the identity with Alison. Her disguise as Red Coat was exposed in the fourth season mid finale when Emily was trapped on a saw at Ravenswood and later got into a fight with Aria who discovered her identity and Charlotte later fell off a platform and escaped. In "A is for Answers" the Liars are under attack by "A" who shoots Ezra Fitz on the rooftop. However, in the fifth-season premiere, the shooter is revealed to be Shana Fring who attempted to kill Alison but was later shoved off a stage by Aria and died from the impact. After all of this, Charlotte fled to France under the Vivian Darkbloom identity to escape custody for Wilden's death but returned. In the series's 100 episode, Charlotte placed a bomb in the Cavanaugh house which detonated, signalling her return to Rosewood. In season five, CeCe breaks into the Vanderwaal home and kidnaps Mona just as she is about to tell the Liars that Alison is "A" and covers up her kidnapping as a homicide. She then brings Mona to the Dollhouse and tortures her and forces her to dress up and act like Alison. Just as the Liars are being brought to jail, CeCe kidnaps them and tortures them inside the Dollhouse. Inside, the Liars discover that Big "A" is named Charles DiLaurentis. CeCe/Charlotte reveals herself as "A" and tells her story; saying that she is transgender, was formerly known as Charles DiLaurentis, and became 'A' because the Liars were happy that Alison was gone. She worked with Sara Harvey, who was the Black Widow and a decoy Red Coat, and was also responsible for the "death" of Alison and the death of Wilden, and after telling her story, she attempts suicide by jumping off Radley but is stopped. She is admitted to Welby State and her reign as "A" finally ends and stays in the psychiatric hospital for five years. When she is released, Charlotte is murdered by Mona Vanderwaal and her death causes the birth of "A.D.", the new Uber A. After her death, it is revealed that Noel Kahn was also working for Charlotte. It is also revealed that her birth mother is Jessica's twin, Mary Drake, and her birth father is Ted Wilson, while Spencer is her sister.
Uber "A"[edit]
Alex Drake as "A"
Uber A, also known as A.D., is the third major "A" to have tormented the Liars. In the show's series finale, Uber A's identity is revealed to be Alex Drake, Spencer's twin sister who was put up for adoption at birth. She desperately craves vengeance over the tragic passing of Charlotte DiLaurentis, who was her half-sister, and is trying to seek out the person responsible. Unlike Mona or Charlotte, Alex does not use any nicknames at first but instead signs their messages with emojis, which differentiates her from the A-Team. This causes Caleb to nickname her Amoji. However, in the sixth-season finale, she begins using the alias "A.D." and kidnaps Hanna, whom she believes is accountable for her sister's homicide.[2] Hanna manages to escape Uber A's clutches and Alex goes after Alison, who the Liars suggested as guilty for her own cousin's murder. Uber A eventually finds out that Alison is innocent after searching her jacket. While Uber A does work on their own, she also works through a new "A-Team" of helpers, known to consist of Jenna Marshall, Sydney Driscoll, and Aria Montgomery, who are assisting them in completing the endgame. The series finale explains that Alex Drake was put up for adoption in exchange for a sum of money (for Mary), but then left at an orphanage by her adopted parents who were concerned for their image. She ran away from the orphanage at ten years old and eventually started working in a bar in London, where Wren Kingston mistook her for Spencer, revealing the existence of Alex's twin and Charlotte. Wren introduces Charlotte and Alex in an airport (just after Charlotte met Archer Dunhill) and they immediately connect, becoming very close in a short amount of time. After Charlotte is released from Welby, she tells Alex that she wishes to return to Rosewood and resume the game, but Alex says she shouldn't go unless she gets to come too, since she wants to meet Spencer. Charlotte says no and describes the Hastings as "toxic people" before leaving for Rosewood, where she was murdered by Mona. Alex is enraged and forces Wren to shoot her so that she looks exactly like Spencer and can successfully impersonate her. She then goes to Rosewood and picks up the game as "Uber A". Alex has made several appearances where she impersonates Spencer, including, but not limited to: The run in with Ezra at the airport where she introduced Wren, the kiss between "Spencer" and Toby just before the latter planned to leave Rosewood with Yvonne, and Hanna's "dream" where she "hallucinated" Spencer while A.D held her hostage. The latter was done so that Alex could find out whether Hanna was telling the truth about killing Charlotte.
The A-Team[edit]
The A-Team is a group of anonymous characters that worked together as "A". The team would work under the orders of the "A" in charge, who has been Mona Vanderwaal, the original leader and founder and CeCe Drake, the second leader. Five years later, Alex Drake, also known as Uber A, assembles a team of their own. This team continues using the same name, though is also referred to as the "A.D.-Team".
Members[edit]
Sara Harvey[edit]
Sara was the right-hand woman to Charlotte and also revealed as an A-Team member halfway throughout the sixth season.[3][4] Sara is revealed as a Red Coat and the Black Widow, hired to pose as a decoy whenever Charlotte couldn't sport the Red Coat disguise.[5][6] She then became Charlotte's friend and ally in the "A" game and assisted her in most of her schemes. Sara was allegedly diagnosed with Stockholm Syndrome following Charlotte's arrest, but later discloses to Alison that she lied under oath, also admitting that she and Charlotte were in fact close friends and she felt as though they were sisters. Later, Sara was possibly enlisted by "A.D." to work with them. However, Sara was killed by Noel Kahn after she tried to reveal more than she should to Emily.
Sydney Driscoll[edit]
Sydney is Uber A's helper for a brief while. She is first seen communicating with them through text messages, when she makes a donation under their name at the Vogel Vision Institute. When Aria and Emily confront her, Driscoll claims that she is simply representing a client who prefers to remain anonymous. However, she returns in the following episode and reveals herself to be "A.D.". She offers Aria the chance to join their team, but Aria realizes that Sydney is communicating with someone through an ear piece, revealing that she's just a minion. Aria asks her why she would join their tormentor and Driscoll replies that she wants to be part of the "winning team". However, Uber A, who reveals herself as Spencer's twin sister Alex Drake, reveals in the series finale that Sydney wasn't involved in the Blind School shooting and joined the A-Team because Alex found out she had been stealing from a bank and she fit the hoodie.[7]
Toby Cavanaugh[edit]
Toby was recruited by Mona to join the A-Team when he got a job in Bucks County. His participation in the team was revealed in the mid-season finale of the third season.[8] He worked hand in hand with Mona and did most of the dirty work for the team, like running down Lucas and attacking Hanna. However, like Mona, he didn't know the identity of Red Coat. Spencer finds out about his betrayal and goes off the deep end, especially after discovering his corpse. However, it is revealed that he is alive and well, with the corpse being a trick by Mona and Red Coat that he says he didn't know about until after. He is also revealed to be a double agent and gets kicked off the team.[9]
Spencer Hastings[edit]
Spencer joined the A-Team briefly near the ending of the third season after having been invited by Mona at the Radley while hospitalized.[10] Initially, Spencer was extremely determined to be part of the team. However, she later unfolds the truth behind the disappearance of Toby and became a double agent as well. Likewise Toby, she got kicked off from the team. She is the "A" who kidnapped Malcolm, causing a break up between Ezra and Aria.[9]
Lucas Gottesman[edit]
Lucas was the personal assistant to Mona. He was blackmailed by Mona and the A-Team into sending texts and doing their dirty work. Lucas claims his blackmail began after Mona discovered he was selling test answers, however Mona later discloses that Lucas was the "A" who gave Emily a massage back in the second season while Mona was off riding with Hanna.[11] During the seventh-season episode "Hold Your Piece", Pastor Ted Wilson reveals to Hanna that he used to run a summer camp for troubled boys, and Charlotte was a camper there prior to her sex change. Wilson is disheartened when describing that he interacted with his offspring without awareness they were related. Ted then showcases Hanna a picture of himself back when he worked at the camp, chaperoning Charles and Lucas, whom he described as his son's "only friend".
Melissa Hastings[edit]
Melissa was blackmailed by Mona into wearing the Black Swan disguise to the Masquerade Ball in order to distract Jenna. Mona threatened to reveal her fake pregnancy if she didn't obey her orders. Later, Melissa got onto the Halloween Train dressed as the Queen of Hearts and drugged Aria.[11] Wilden then attempted to push her off of the train in a box with Garrett's dead body. It is implied that she was once again blackmailed. It is implied in "A Dark Ali" that Melissa is once again working for "A", as she is seen handing a recording (presumed stolen by "A") to a man resembling Cyrus Petrillo and later implies to Spencer that "A" has something in store for Ali and the Liars.
Darren Wilden[edit]
Wilden was also part of the team as he was the Queens of Hearts responsible for trying to kill Spencer. He also murdered Garrett Reynolds fearing he'd expose him as a crooked cop and placed his corpse in a box beside a fainted Aria.[11] Wilden's reasoning for helping the team is unknown but implied to be blackmail.
Jenna Marshall[edit]
Jenna was a member of the A-Team during the reign of Big A and was also working anonymously for Uber A. She remains around Rosewood in "Along Comes Mary" and befriends Sara Harvey. Meanwhile, Aria Montgomery and Emily Fields discover that Jenna was on Archer's payroll for unknown reasons. On the episode's closing scene, Marshall and Sara are having drinks at The Radley when an unknown figure approaches the two and reveals themselves to be Noel Kahn, who proceeds to join the duo. When confronted by Emily in regards to her involvement with Archer during "Wanted: Dead or Alive", Jenna admits she befriended Charlotte DiLaurentis after reading about her stay at Welby and reached out. In a flashback, Charlotte enlists Jenna's help to track down the whereabouts of her birth mother and come up with an alias for Archer. The pseudonym "Elliott Rollins" was later created so Archer could deliberately meet Alison and take advantage of her good intentions to benefit Charlotte's eventual release from the psychiatric hospital. In "The DArkest Knight" all of the Liars get a text message, ordering them to head over to 1465, Elm Street. After being lured to an abandoned school for blind students, they're held hostage by Noel and Jenna, with Marshall tracking them down at gunpoint. During the cat-and-mouse chase, Jenna takes aim at the Liars only to backfire, until a second gunshot is heard and it injures Spencer. As Marshall prepares to finish her off, Mary Drake suddenly emerges from behind and knocks her out. While Drake attempts to help Spencer, an unknown figure drags Jenna away from the building. On the closing scene of the episode, the anonymous entity places her in the back of a van, while she questions them if they were responsible for the gunshot that hit Spencer. As the mysterious figure proceeds to rip off an old man's mask and toss it over to Jenna's side, Marshall feels it up and realizes that A.D. was the one who rescued her. At the end of "Playtime", Jenna is seated in A.D.'s lair, sipping tea. She thanks the unidentified individual for the drink and reminds them of their promise to update her on the "game". Dressed in a nurse's uniform, A.D. drops a binder on Marshall's lap with pages of information written in braille. After Jenna reads a paragraph, she mutters the word "endgame" and grins in delight. During "These Boots Were Made for Stalking", Jenna walks into the police station in order to come clean about her actions and interrupts a conversation between Spencer and detective Marco Furey. Marshall reports that she kept a low profile after the events that took place at the abandoned school for blind students to avoid being harmed by Noel. According to Jenna, Noel was accountable for Sara Harvey's homicide and she feared to be his ensuing victim. Kahn recruited Jenna with the assertion that Charlotte left enough money in her will to afford Marshall another eye surgery. Nevertheless, Jenna suspected Noel of stealthily plotting to steal the cash all to himself since his parents had financially cut him off. In an attempt to spare her life, Marshall brought a gun to the deserted sight school as an act of self-defense and pretended to hold a grudge against the Liars. After Jenna describes her side of the story, Furey orders one of his associates to escort Marshall to a conference room so she can make an official statement. As Jenna exits the room, Spencer claims that she's an unreliable narrator. However, Furey informs Spencer that the authorities don't have enough evidence against Marshall because the bullet that injured Spencer didn't match the gun found at the location. Later in the episode, Caleb confronts Jenna stating that the authorities were already detecting holes in her allegations. However, Marshall assures Caleb they won't be able to prosecute her since Noel was the only person who could contradict her statement. In the series finale, Spencer's twin, Alex Drake, is revealed to be "A.D.". She reveals that Jenna was looking for her and recruited Noel to help. However, Jenna was desperate for another chance to see and offered to help her in the game.
Noel Kahn[edit]
Noel Kahn returned to Rosewood to team up with Jenna Marshall and Sara Harvey. Kahn served as one of Charlotte's former minions and worked for her at the Dollhouse, having been responsible for placing blood all over Spencer Hastings to convince she had hurt someone. Noel became the prime suspect for Uber A, particularly after Alison reveals that he pushed a girl down a flight of stairs when he was drunk during a UPenn frat party. Hanna abducts him at the end of "The Wrath of Kahn" in an attempt to obtain a video confession that proves he's their tormentor. In the following episode "The DArkest Knight", she instead ends up slashing his leg with a knife in order to test his DNA and see if it matches Mary Drake's. The results later come back negative and Kahn ends up escaping. Noel and Jenna later lure the Liars to an abandoned school for blind students so they could be held hostage and eventually murdered. During a cat-and-mouse chase, Kahn ends up stumbling upon an axe that decapitates his head after failing to fight Emily and Hanna. In the following episode, "Playtime", Detective Marco Furey informs Spencer that Jenna and Noel frequently visited Archer Dunhill at Welby. During "These Boots Were Made for Stalking", Jenna walks into the police station in order to come clean about her actions and interrupts a conversation between Spencer and detective Marco Furey. Marshall reports that she kept a low profile after the events that took place at the abandoned school for blind students to avoid being harmed by Noel. According to Jenna, Noel was accountable for Sara Harvey's homicide and she feared to be his ensuing victim. Kahn recruited Jenna with the assertion that Charlotte left enough money in her will to afford Marshall another eye surgery. Nevertheless, Jenna suspected Noel of stealthily plotting to steal the cash all to himself since his parents had financially cut him off. In an attempt to spare her life, Marshall brought a gun to the deserted sight school as an act of self-defense and pretended to hold a grudge against the Liars. However, when Caleb later confronts Jenna about the authorities detecting holes in her allegations, she informs him that the only person who could contradict her side of the story was Noel.
Aria Montgomery[edit]
Aria is "A.D.'s" helper. Aria is given the offer to join the team in "Power Play". She accepts in the following episode and begins supplying information to Uber A. After the Liars discover Lucas' graphic novel, Aria is sent by Uber A to retrieve it. Once she delivers it, she is given an "A" hoodie in return. She breaks into Alison's house sporting the disguise and trashes the nursery for her baby. In the next episode, Aria is sent by "A.D." to deliver a "gift" to the Hastings family. She connects to their Bluetooth and leaves a burner phone there to play a video recording of Peter and Mary discussing Jessica's murder. She later gets back into her "A" disguise and breaks into Alison's house to put the puzzle piece onto the and retrieve her file. "A.D." contacts Aria again and gives her a phone to communicate on. "A.D." asks Aria to meet them and to wear the uniform to do so. Mona overhears the call and tells the Liars of Aria's involvement with the A-Team. Aria gets into her "A" hoodie and goes to meet "A.D.", only to be confronted by the Liars. She then officially defects from the team and rejoins the Liars.
Mary Drake[edit]
Mary joins the A.D.-Team after the time jump, when Alex helps break her out of prison and then helps her with kidnapping Spencer and keeping her locked away in their bunker. When Alex tries to kill Spencer, Mary tries to convince her to just keep her locked up, but Alex refuses and punches her to keep her from interfering. Mary and Alex are then kidnapped by Mona and kept as her dolls in her own personal dollhouse.
Wren Kingston[edit]
Wren is one of the helpers to Alex. He shoots her so that she will have the same scar as Spencer and then later comes to Welby to kill Mona as "A.D." for Alex, only stopping once Mona says she can help get Mary out. Alex kills Wren so that she doesn't have to break up with him in order to get her endgame wishes. Despite Wren being the only person to know almost everything about Alex's game, he doesn't participate much during the actual game, only doing a few things for Alex.
Other "A's"[edit]
Caleb Rivers[edit]
Caleb used the identity of "A" to text Hanna in Season 3, in order to trick her into meeting him. He sent her the text "The Apple Rose Grille at closing time. Go alone or Caleb pays. -A" to find out this information from her about the new "A".
Shana Fring[edit]
Shana pretended to be "A" to attack the Liars in New York. She donned a black hoodie and attacked them at the coffee shop, only to end up shooting Ezra instead, who had found out her identity. In the following episode, she continued to hunt down the Liars, and sent a group of black hoodies to trick them. The black hoodies used the alias "A" during their taunting of the Liars. Shana revealed herself to the girls and revealed that she wanted justice for Jenna. The Liars falsely believed that Shana was Big A.[12]
Disguises[edit]
During the TV series, the antagonists used various disguises at parties and events, in order to watch over the girls. They are:
Red Coat[edit]
Main article: Red Coat (Pretty Little Liars)
Red Coat is a disguise used by two members of the A-Team. CeCe Drake took on the disguise to lead the A-Team and go out in public, while she hired Sara Harvey to act as a decoy whenever she couldn't sport the disguise in her assignments.
The Black Widow[edit]
The Black Widow is a previously anonymous character who attended detective Darren Wilden's funeral in "'A' Is for A-l-i-v-e". The disguise is all black clothing, with her face concealed by a black veil. The Black Widow is shown to be a part of the A-Team, when she is seen inside the "A" R.V. placing a Mona doll with the rest of the "A" doll collection. She then lifts up her veil to reveal a burned Ali mask underneath, revealing that she was the Red Coat at the Lodge. In the fifth season, the disguise is seen inside one of "A"'s lairs.[13] In "Game Over, Charles", it is revealed that Sara Harvey was the Black Widow. Charlotte sent her to Wilden's funeral to make sure he was deceased.[3] In "Of Late I Think of Rosewood", Sara shows up to Charlotte's funeral in a variation of the disguise, though this time revealing her face.[14]
In a nightmare that Alison had during "How the 'A' Stole Christmas", her mom, Jessica DiLaurentis shows up as the Black Widow.
The Queen of Hearts[edit]
The Queen of Hearts is a previously anonymous character that made an appearance during the third season's Halloween special, "This Is a Dark Ride".[15] In the fourth season's premiere, it is revealed that there were actually two of them in the Halloween train, Melissa Hastings and Darren Wilden. Wilden attacked Spencer and fought Paige, while Melissa drugged Aria and took her body. Wilden also murdered Garrett Reynolds fearing he'd expose his corrupt activities and Melissa later admits to Spencer that she was blackmailed into doing his bidding. However, in Mona's footage, evidence shows that Wilden tried to abandon the train and Melissa is heard ordering him to stay. Wilden would later place a fainted Aria in a box beside Garrett's corpse and then gathered with Melissa in an attempt to push them off the train. They fled the scene once Aria regained her consciousness and stabbed Wilden.[11]
The Black Swan[edit]
The Black Swan is a previously anonymous character that made an appearance during the Masquerade Ball.[16] Melissa was revealed to be the person behind the disguise in "Birds of a Feather". She claimed that "A" (Mona) threatened her, stating that her false pregnancy would've been exposed if she did not distract Jenna during the event. The disguise is inspired by Odile from Swan Lake.
The Black Hoodie[edit]
Of course, the black hoodie has been the most significant disguise over the years and probably the most well known. Almost every single "A" has worn the signature black hoodie and it will be one of the biggest things for as long as Pretty Little Liars will be remembered. The disguise has been used by Mona, Charlotte, Toby, Spencer, Lucas, Sydney, Aria, Wren, and Alex.
References[edit]
Jump up ^ "Pretty Little Liars - Pilot". ABC Family. Retrieved 24 March 2014.
Jump up ^ Swift, Andy (15 March 2016). "Pretty Little Liars Season Finale Recap: [Spoiler]'s Twin Revealed". TVLine. Retrieved 21 April 2016.
^ Jump up to: a b "Game Over, Charles". Pretty Little Liars. 2015.
Jump up ^ Weiss, Shari (11 August 2016). ""Pretty Little Liars" Finale Recap: "Game Over, Charles" (VIDEO)". Gossip Cop. Retrieved 19 May 2016.
Jump up ^ Sorren, Martha. "Sara Harvey Is Red Coat On 'Pretty Little Liars' & She Was In Cahoots With CeCe". Bustle. Retrieved May 13, 2016.
Jump up ^ Highfill, Samantha. "Pretty Little Liars boss definitively answers who was behind the show's biggest mysteries". Entertainment Weekly. Retrieved May 13, 2016.
Jump up ^ http://freeform.go.com/shows/pretty-little-liars/news/who-is-sydney-on-pretty-little-liars
Jump up ^ "The Lady Killer". Pretty Little Liars. 2012.
^ Jump up to: a b "A dAngerous gAme". Pretty Little Liars. 2013.
Jump up ^ "What Becomes of the Broken Hearted". Pretty Little Liars. 2013.
^ Jump up to: a b c d "'A' is for A-l-i-v-e". Pretty Little Liars. 2013.
Jump up ^ I. Marlene King [@imarleneking] (6 June 2017). "@SherrieScream4 pretending" (Tweet) – via Twitter.
Jump up ^ "Miss Me x 100". Pretty Little Liars. 2014.
Jump up ^ "Pretty Little Liars on Twitter". Twitter. Retrieved 2017-05-12.
Jump up ^ "This Is a Dark Ride". Pretty Little Liars. 2014.
Jump up ^ Director: Glatter, Lesli Linka. Writer: King, I. Marlene (March 19, 2012). "Unmasked". Pretty Little Liars. Season 2. Episode 25. ABC Family.
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v
t
e
Pretty Little Liars
Episodes
Season 1
"Pilot"
"For Whom the Bell Tolls"
Season 2
"UnmAsked"
Season 3
"It Happened 'That Night'"
Season 4
"'A' Is for A-l-i-v-e"
"Grave New World"
"Free Fall"
"A Is for Answers"
Season 5
"Miss Me × 100"
"How the 'A' Stole Christmas"
Season 6
"Game On, Charles"
"Game Over, Charles"
"Of Late I Think of Rosewood"
"Charlotte's Web"
"Where Somebody Waits For Me"
"Hush, Hush, Sweet Liars"
Season 7
"Tick-Tock, Bitches"
"Bedlam"
"The Talented Mr. Rollins"
"Hit and Run, Run, Run"
"Along Comes Mary"
"Wanted: Dead or Alive"
"Original G'A'ngsters"
"Exes and OMGs"
"The Wrath of Kahn"
"The DArkest Knight"
"Playtime"
"These Boots Were Made for Stalking"
"Hold Your Piece"
"Power Play"
"In the Eye Abides the Heart"
"The Glove That Rocks the Cradle"
"Driving Miss Crazy"
"Choose or Lose"
"Till Death Do Us Part"
Characters
"A"
Alex Drake
Alison DiLaurentis
Aria Montgomery
Charlotte Drake
Emily Fields
Hanna Marin
Jenna Marshall
Mary Drake
Melissa Hastings
Mona Vanderwaal
Red Coat
Sara Harvey
Spencer Hastings
Sydney Driscoll
Related
Book series
2006 novel
Rosewood, Pennsylvania
Ravenswood
Pretty Little Liars: The Perfectionists
Pretty Dirty Secrets
Category
Retrieved from "https://en.wikipedia.org/w/index.php?title=A_(Pretty_Little_Liars)&oldid=837572820"
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Pretty Little Liars characters
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This page was last edited on 21 April 2018, at 17:56.
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Pretty Little Liars (TV series)

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Pretty Little Liars (book)

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Charlotte DiLaurentis

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Stockholm Syndrome

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Lucas Gottesman

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Darren Wilden

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Caleb Rivers

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Unmasked (Pretty Little Liars)

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