SchemeofWork

Scheme of work for History and Philosophy of Acidity, as a route to establishing concepts of acidity. || **Comments** || Indicators (e.g. Boyle and Lemery); Instruments; [|Boyle paper on elements] Models and causative nature of explanations.(Lemery's shape of particles)
 * **Topic ** || **History and philosophy**
 * How do acids behave? Behaviour of acids in solution in respect of indicators, reaction with active metals, neutralisation of bases. || **History:**
 * Philosophy**:

=Syrup of violets= A preparation made from SYRUP and flavoured with the flowers of the VIOLET. Making a syrup of the flowers was probably the most common way of preserving them for use throughout the year, so that it is found in most shops selling APOTHECARY. Since it was believed to have some medicinal properties it may often be noted expressed wholly or partially in Latin as in 'Sir' vyolaru' 1 li di' [Inventories (1624)], and/or heavily abbreviated as in 'S violaru' [Inventories (1573)]. John Houghton indicated that syrup of violets retained the blue colour of its flowers, as well as pointing to a possible adulterant in NEPHRITIC WOOD [Houghton]. Whether it was ever used for this purpose, is not known. It is apparent, judging from valuations, that the quality of this syrup varied, being costed from 2s LB or less [Inventories (1634)], to double that [Inventories (1665)]. This may be explained by the two recipes given in an anonymous Book of Simples. In the first, the violet flowers were infused in boiling water. The liquor was then strained, the sugar added and the whole reheated only sufficiently to dissolve the sugar. In the second, no water was added, but a thick syrup was obtained by gradually heating alternate layers of the flowers and the sugar [Anon (1908)]. A late edition of Nicholas Culpeper's English Physician' concluded that the syrup 'is of the most use, and of better effect, being taken in some convenient liquor; and if a little juice or syrup of lemons be put to it, or a few drops of the oil of vitriol, it is made thereby the more powerful to cool the heat, and quench the thirst, and giveth to the drink a claret wine colour, and a fine tart relish pleasing the taste' [Culpeper (1792)]. A recipe for syrup of violets was still included in the London Dispensatory of 1746, but it was probably used by then primarily to mask the taste of unpleasant medicines [Pemberton (1746)]. It is the only product of violets still included by that date. OED earliest date of use: 1400-50 under Violet || **Avoidance of whiggishness:** Classification of materials based on behaviour (macroscopic v sub-microscopic explanations). Novel tools to explore phenomena (indicators) History of indicators; NoS as classification based on regularity; Induction; Regularity Paradigm Biography of Boyle Biography of Lemery Causative nature of explanations (a simplified philosophical approach) Modelling Regularity Induction Paradigm and paradigm shift || [|Systematisation and terminology (Lavoisier)] [|Morveau paper on phlogiston] [|Lavoisier paper on elements] [|Macquer paper on elements] Models and causative nature of explanations (all acids contain oxygen, then enshrined in nomenclature). Acids contain an empowering feature (oxygen or acid-maker) || **Avoidance of whiggishness:** history of search for causation, and existence of common phenomena (must mention dates of sulphur and phosphorus discoveries and references) Terminology, especially naming of acids with different proportions of oxygen Biography of Lavoisier Biography of Morveau Biography of Macquer Dualism to explain nature of acid and base. || [|Davy (1810)], [|and Davy (1810)] and [|(Davy (1810) Wikipedia)] paradigm shift in the face of conflicting evidence (can the existing paradigm explain all of the data). Ideas coexisting in the face of lack of resolution. || **Avoidance of whiggishness:** lack of clarity about the nature of an element, and of methods to identify elemental nature of a substance. Davy biography Tests for power of theories Paper on why the two paradigms existed in parallel? || [|Davy (1815)], [|and Davy (1815)] and [|(Davy (1815) Wikipedia)]. [|Davy discovery of chlorine]. Absence of instruments (to await Arrhenius) Davy and Arrhenius were focused on the solute alone. It took more precise measurements (and better instruments) to investigate the role of the solvent in the 1920s Concept of element Instruments in chemistry Paper on why the solvent role was neglected? || Potential for repeating his experiments but getting at similar data. Perhaps could use Kohlrausch's data if more easily available. || **History:** [|Arrhenius (Wikipedia)] [|Arrhenius paper on dissolving] [|Sorenson paper on pH] [|Negative pH and some other ideas discussed by an African] [|Kohlrausch's work (variously reported as around1875-79: he was born in 1840) on instruments for conductance in solution] He used a telephone for detecting alternating current (Wheatstone Bridge and an induction coil for AC) [|Kohlrausch's Bridge] and [|Kohlrausch from Wikipedia] [|His paper scanned in] with work from Faraday and Hittorf showing their instruments are here. [|Pictures of Kohlrausch's Bridge] [|He objected to a street car line outside to get greater precision] [|Hitchcock's paper (1923) using the Kohlrausch Bridge] [|Stubb's paper on conductance of carbon dioxide solutions] Cause and effect explanations Quantitative work as an indicator of explanatory power || **Avoidance of whiggishness:** Development and availability of Kohlrausch Bridge as a precursor. Terminology (ions, names of electrodes) Biography of Arrhenius Biography of Sorenson Biography of Kohlrausch Instruments used by Arrhenius and his challenges in measuring conductivity while avoiding polarisation || [|Brønsted biography]) [|Brønsted description] (1923) [|Brønsted's paper] [|Lowry Described] (1923) [|ChemTeam's report of Lowry's work] [|Wikipedia report] [|A short discussion of paradigm shift] || **Avoidance of whiggishness:** Focus on need for non-aqueous systems, including ability to work with anhydrous liquid ammonia under pressure in titrations. Non-aqueous solvents Biography of Brønsted Biography of Lowry Research on learning B-L theory [|here] || [|Lewis acid from Wikipedia] A theory that did not give rise to a paradigm shift! Needs a paper on why not. Linking with another theory (Lewis electron pair theory of 1916) Usefulness of too broad a theory of acids. || **Avoidance of whiggishness:** Focus on significance of electron-pair model and Lewis' team desire to apply to a range of chemical explanations. Biography of Lewis Lewis electron pair theory Uses of Lewis acids How to choose an appropriate theory to study for different topics || [|Solvent theory (increasing solvonium cations in an autoionising solvent)] [|Ascribed to Edward Franklin in 1905] [|Liebig definition, 1838, (hydrogen replaced by metal)] [|Usanovic (acid accepts negative species)] [|Lux-Flood definition (acid is oxide acceptor)] [|Pearson (hard and soft acids)] Theories that did not give rise to paradigm shifts! Needs a paper on why not. || **Avoidance of whiggishness:** Focus on availability of non-aqueous solvents and need to develop an explanation for reactions in these systems Biography of Edward Franklin Biography of Liebig Biography of Usanovic Biography of Lux Biography of Flood Biography of Pearson Theories that did not give rise to paradigm shifts! Needs a paper on why not. ||
 * Learner material (in appropriate language):** Terminology;
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 * Oxo-acids - oxides of non-metals phosphorus and sulphur. Acids as oxygen containers || **History:**
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 * Hydracids - dual concepts of acids (oxygen and hydrogen-containing) || **History:**
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 * The role of water - distinguishing between the solute and the solution. || **History:**
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 * Ion formation (Arrhenius, 1884).
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 * Proton transfer (Brønsted-Lowry, 1923) || **History:**
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 * Lewis acids (1923) || **History:**
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 * Other theories - these are included for completeness or for extension work || **History:**
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