Blue Bottle Experiment
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The blue bottle experiment is a color-changing
redox Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is t ...
chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...
. An aqueous solution containing
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
,
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...
,
methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. As a medication, it is mainly used to treat methemoglobinemia. It has previously been used for treating cyanide poisoning and urinary trac ...
is prepared in a closed bottle containing some air. Upon standing, it spontaneously turns from
blue Blue is one of the three primary colours in the RYB color model, RYB colour model (traditional colour theory), as well as in the RGB color model, RGB (additive) colour model. It lies between Violet (color), violet and cyan on the optical spe ...
to colorless due to reduction of methylene blue by the alkaline glucose solution. However, shaking the bottle oxidizes methylene blue back into its blue form. With further shaking, this color-change cycle can be repeated many times. This experiment is a classic chemistry demonstration that can be used in laboratory courses as a general chemistry experiment to study
chemical kinetics Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a ...
and
reaction mechanism In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical reaction occurs. A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage ...
. The reaction also works with other
reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are common reducing agents include hydrogen, carbon ...
s besides glucose and other
redox indicator A redox indicator (also called an oxidation-reduction indicator) is an indicator which undergoes a definite color change at a specific electrode potential. The requirement for fast and reversible color change means that the oxidation-reduction Ch ...
dyes besides methylene blue.


Reactions


History and general concept

The mechanism of the blue bottle experiment requires an understanding of
rates Rate or rates may refer to: Finance * Rate (company), an American residential mortgage company formerly known as Guaranteed Rate * Rates (tax), a type of taxation system in the United Kingdom used to fund local government * Exchange rate, rate ...
and mechanisms of complex interacting chemical reactions. In complex chemical reactions, individual sub-reactions can occur simultaneously but at significantly different rates. These, in turn, can be affected by reagent
concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', '' number concentration'', ...
and
temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
. In most cases, the overall reaction rate is determined by the fastest single component reaction. However, when some processes form intermediate molecules which then react in other processes to form the end product, the rate of the overall reaction is determined by the rate of the slowest reaction. In such circumstances the intermediate products are usually in a steady state at low concentrations because they are highly reactive. Equilibrium state requires that all reaction forward and backward mechanism happens at the same rate. Thus, the overall net reaction is determined by the sum of all the mechanism steps where the rate depends on the concentration and temperature. The blue bottle experiment illustrates this principle of interacting reactions with different rates. The blue bottle experiment requires only three reagents:
potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...
solution,
dextrose Glucose is a sugar with the molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae during photosynthesis from water an ...
solution, and dilute
methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. As a medication, it is mainly used to treat methemoglobinemia. It has previously been used for treating cyanide poisoning and urinary trac ...
solution. These reagents are added to a flask, mixed, and the flask is stoppered. The initial color of the solution is blue, but upon standing for a short interval it spontaneously fades to colorless, as the alkaline dextrose solution reduces the methylene blue to colorless leuco-methylene blue. Shaking the flask causes oxygen present in the head space air to dissolve in the solution and
oxidize Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
the leuco-methylene blue back to its colored form again. Another variation uses
methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. As a medication, it is mainly used to treat methemoglobinemia. It has previously been used for treating cyanide poisoning and urinary trac ...
in water,
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
, and
caustic soda Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base and alkali t ...
(
NaOH Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base and alkali t ...
). There are many versions of the experiment, however, unlike the classical version where dye is necessary to use as a catalyst for the reaction, the green and rapid versions undergo autoxidation even in the absence of the dye. In the past, it was thought that the reaction occurred by the oxidation of an
aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...
group to a
carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl ...
under
alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...
conditions. For instance, glucose would be oxidized to
gluconate Gluconic acid is an organic compound with molecular formula C6H12O7 and condensed structural formula HOCH2(CHOH)4CO2H. A white solid, it forms the gluconate anion in neutral aqueous solution. The salts of gluconic acid are known as "gluconates". ...
by
oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
. However, the experiment also works with compounds such as
vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription di ...
and benzoin, which do not contain an aldehyde group. Thus, the reaction is actually the oxidation of an
acyloin In organic chemistry, acyloins or α-hydroxy ketones are a class of organic compounds of the general form , composed of a hydroxy group () adjacent to a ketone group (). The name ''acyloin'' is derived from the fact that they are formally deri ...
or related α- hydroxy
carbonyl In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double bond, double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such a ...
group, which is a structural feature of glucose, to a 1,2-diketone. The reduced redox dye (colorless state) is formed from oxidized redox dye (blue). The color-change that occurs in the blue bottle experiment has features of a clock reaction, in which a visible change in the concentration of one or more reagents suddenly occurs upon the exhaustion of a limiting reagent. For example, the limiting reactant, oxygen, is consumed by another reactant, benzoin, with the help of
safranin Safranin (Safranin O or basic red 2) is a biological stain used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring cell nuclei red. This is the classic counterstain in both Gram stains and endo ...
as a catalyst. Once the limited amount of oxygen has been used up, the catalyst is unable to change forms, and as a result, the solution changes color.


Classical version

The aqueous solution in the classical reaction contains
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
,
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...
and
methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. As a medication, it is mainly used to treat methemoglobinemia. It has previously been used for treating cyanide poisoning and urinary trac ...
. In the first step an
acyloin In organic chemistry, acyloins or α-hydroxy ketones are a class of organic compounds of the general form , composed of a hydroxy group () adjacent to a ketone group (). The name ''acyloin'' is derived from the fact that they are formally deri ...
of glucose is formed. The next step is a
redox reaction Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
of the acyloin with methylene blue in which the glucose is oxidized to
diketone In organic chemistry, a dicarbonyl is a molecule containing two carbonyl () groups. Although this term could refer to any organic compound containing two carbonyl groups, it is used more specifically to describe molecules in which both carbonyls ...
in alkaline solution and methylene blue is reduced to colorless leucomethylene blue. If there is enough oxygen available (i.e., after shaking the bottle), leucomethylene blue is immediately re-oxidized to methylene blue and the blue color of the solution persists. However, when the solution is left to rest, the dissolved oxygen is gradually irreversibly consumed, and at the point where it has been completely exhausted, the glucose reduction of methylene blue proceeds unopposed and the color of the solution rapidly disappears. The reaction is
first order In mathematics and other formal sciences, first-order or first order most often means either: * "linear" (a polynomial of degree at most one), as in first-order approximation and other calculus uses, where it is contrasted with "polynomials of high ...
in glucose, methylene blue and hydroxide ion and zero-order in oxygen. The process can be described as a
pseudo first order reaction In chemistry, the rate equation (also known as the rate law or empirical differential rate equation) is an empirical differential mathematical expression for the reaction rate of a given reaction in terms of concentrations of chemical species and ...
, and can be used to illustrate the changing concentrations of the reagents over the course of the reaction as the solution changes from blue back to colorless. The final glucose oxidation products besides sodium gluconate have been identified as -arabino-hexos-2-ulose ( glucosone), the anion of -arabinonate after splitting off of a formate anion and arabinonic acid.


Green version

Wellman and Noble proposed a new formulation for the Blue Bottle experiment in which vitamin C serves as a reducing agent instead of glucose; the methylene blue and oxygen are still used. Copper is added as a catalyst for the reoxidation of leucomethylene blue to
methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. As a medication, it is mainly used to treat methemoglobinemia. It has previously been used for treating cyanide poisoning and urinary trac ...
. These modifications give an experiment that generates a smaller amount of waste that is less corrosive and easier to neutralize, and therefore is an example of
green chemistry Green chemistry, similar to sustainable chemistry or circular chemistry, is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances. Wh ...
modification.


Rapid version

The Chen autoxidation of benzoin had performed a similar experiment with respect to the classical and green versions. It was found that the
traffic light Traffic lights, traffic signals, or stoplights – also known as robots in South Africa, Zambia, and Namibia – are signaling devices positioned at intersection (road), road intersections, pedestrian crossings, and other locations in order t ...
and vanishing valentine experiments can become successful regardless of whether a sugar is added. One variation is more rapid, with the number of color change cycles do not last as long as the classical and green versions because the reactants are present in smaller amounts; also, the reducing agent for this experiment is benzoin, which is added to help increase the number of cycles in the solution. Moreover, the usable period in this experiment is quite short. Although the experiment is prepared overnight, the reducing agent can be added at any time to be able to observe the solution more.


Enzymatic version

Zhang, Tsitkov, and Hess from Columbia University proposed an enzymatic version of the "blue bottle experiment". They named it the "green bottle experiment", since the system is colored green and the reagents are safer than classical approaches. The experiment is performed in a clear glass vial containing two common enzymes (
glucose oxidase The glucose oxidase enzyme (GOx or GOD) also known as notatin (EC number 1.1.3.4) is an oxidoreductase that catalyses the oxidation of glucose to hydrogen peroxide and D-glucono-δ-lactone. This enzyme is produced by certain species of fungi an ...
and
horseradish peroxidase The enzyme horseradish peroxidase (HRP), found in the roots of horseradish, is used extensively in biochemistry applications. It is a metalloenzyme with many isoforms, of which the most studied type is C. It catalyzes the oxidation of various or ...
),
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (abbreviated as ABTS) in PBS buffer. A thin layer of oil is used to block the solution from the air. The solution initially turns green and then turns colorless with the depletion of dissolved oxygen. Shaking the solution introduces fresh oxygen and colors the solution green again until the oxygen is consumed. This version relies on three enzymatic reactions. First, the glucose oxidase catalyzes the oxidation of glucose in the presence of oxygen and produces hydrogen peroxide. Second, the horseradish peroxidase utilizes the hydrogen peroxide to oxidize ABTS to its radical cationic form, ABTS+•. As the dissolved oxygen is consumed in the solution, the third reaction occurs: glucose oxidase catalyzes the reduction of ABTS+• back to ABTS in the presence of glucose. This system can also form beautiful patterns arising from reaction-driven Rayleigh–Bénard convection.


Variation of dyes

The chemical reactions and mechanism in the blue bottle experiment rely on the oxidation of a sugar with the aid of air and a redox dye in a basic solution. Other variations of this reaction have been reported that use four families of
redox Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is t ...
dyes:
thiazines Thiazine is an organic compound containing a ring of four carbon, one nitrogen and one sulfur atom. There are three isomers of thiazine, 1,2-thiazine, 1,3-thiazine, and 1,4-thiazine, which differ by the arrangement of the nitrogen and sulfur ato ...
,
oxazines Oxazines are heterocyclic organic compounds containing one oxygen and one nitrogen atom in a cyclohexa-1,4-diene ring (a doubly unsaturated six-membered ring). Isomers exist depending on the relative position of the heteroatoms and relative posit ...
, azines, and
indigo carmine Indigo carmine, or 5,5′-indigodisulfonic acid sodium salt, is an wikt:organic salt#English, organic salt derived from Indigo dye, indigo by aromatic sulfonation, which renders the compound soluble in water. Like indigo, it Blue#Colourants, ...
have all been reported to work with
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
and
caustic soda Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base and alkali t ...
.


Chemical traffic light experiment

The chemical traffic light is a color-changing redox reaction that is related to the blue bottle experiment. One of the early formulas consists of
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
,
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...
,
indigo carmine Indigo carmine, or 5,5′-indigodisulfonic acid sodium salt, is an wikt:organic salt#English, organic salt derived from Indigo dye, indigo by aromatic sulfonation, which renders the compound soluble in water. Like indigo, it Blue#Colourants, ...
(dye), and
water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
. Another formula consists of
indigo carmine Indigo carmine, or 5,5′-indigodisulfonic acid sodium salt, is an wikt:organic salt#English, organic salt derived from Indigo dye, indigo by aromatic sulfonation, which renders the compound soluble in water. Like indigo, it Blue#Colourants, ...
,
ascorbic acid Ascorbic acid is an organic compound with formula , originally called hexuronic acid. It is a white solid, but impure samples can appear yellowish. It dissolves freely in water to give mildly acidic solutions. It is a mild reducing agent. Asco ...
(
Vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription di ...
),
sodium bicarbonate Sodium bicarbonate ( IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cat ...
,
sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...
,
copper(II) sulfate Copper(II) sulfate is an inorganic compound with the chemical formula . It forms hydrates , where ''n'' can range from 1 to 7. The pentahydrate (''n'' = 5), a bright blue crystal, is the most commonly encountered hydrate of copper(II) sulfate, whi ...
,
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...
and
water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
. By doing so,
chemical waste Chemical waste is any excess, unused, or unwanted chemical. Chemical waste may be classified as hazardous waste, non-hazardous waste, universal waste, or household hazardous waste, each of which is regulated separately by national government ...
and the level of
corrosive Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
chemicals is reduced. The amount of solid chemicals dissolved in the experiment could be reduced from 60 grams to 6 grams. And the pH could be lowered from 13 to 3 which is easier to neutralize the pH to 7 by adding
baking soda Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt (chemistry), salt compose ...
before disposal. Also, it is safer and the reactions also occur faster and are easier to perform. At first, all chemicals are added together and the color appears yellow. After shaking, the color turns green and then changes to red after it is left untouched. When further observed, the color turns back to yellow, which is why the solution is called the chemical traffic light. This reaction can be repeated many times, but it needs additional
oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
or
indigo carmine Indigo carmine, or 5,5′-indigodisulfonic acid sodium salt, is an wikt:organic salt#English, organic salt derived from Indigo dye, indigo by aromatic sulfonation, which renders the compound soluble in water. Like indigo, it Blue#Colourants, ...
. This reaction occurs by oxidation and reduction of the solution where alkaline glucose solution is acting as a
reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are common reducing agents include hydrogen, carbon ...
. The glucose solution is added to the solution containing
indicator Indicator may refer to: Biology * Environmental indicator of environmental health (pressures, conditions and responses) * Ecological indicator of ecosystem health (ecological processes) * Health indicator, which is used to describe the health o ...
(dye indigo carmine) the color changes occur. This reaction is also known as
chemical clock A chemical clock (or clock reaction) is a complex mixture of reacting chemical compounds in which the onset of an observable property (discoloration or coloration) occurs after a predictable induction time due to the presence of clock species at ...
experiment because concentrations of the products and reactants changed over the specific period. When the solution is shaken, oxygen dissolves in the solution and oxidizes indigo carmine. Solution becomes red if a small amount of oxygen is dissolved, and green if all of indigo carmine is oxidized. The solution will turn back to original yellow color when the concentration of oxygen level drops. File:Chemical traffic light reaction time-lapse.webm, Chemical traffic light reaction time-lapse File:Chemical traffic light reaction (yellow).jpg, Chemical traffic light reaction (yellow) File:Chemical traffic light reaction (red).jpg, Chemical traffic light reaction (red) File:Chemical traffic light reaction (green).jpg, Chemical traffic light reaction (green)


Vanishing valentine experiment

The vanishing valentine experiment is another chemical reaction related to the blue bottle experiment. This reaction occurs when water,
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
,
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...
, and
resazurin Resazurin (7-Hydroxy-3''H''-phenoxazin-3-one 10-oxide) is a phenoxazine dye that is weakly fluorescent, nontoxic, cell-permeable, and redox‐sensitive. Resazurin has a blue to purple color above pH 6.5 and an orange color below pH 3.8. It is u ...
is mixed in a flask. When the solution is shaken, it turns from light blue to a reddish color. The solution turns back to a light blue after being left to stand for a while. This reaction can be repeated several times. After mixing all the components, shake the bottle and the color will turn to red or pink depend on the amount of resazurin in the solution. More resazurin will result in more time needed for the solution to turn back the color and the intensity of the red color. The chemical reaction stimulates glucose to reduce resazurin to resorufin. It would then be reduced again into a colorless compound called dihydroresorufin. When dihydroresorufin is shaken, it is oxidized back to resorufin. This is due to the fact that shaking it results oxygen in the bottle to oxidized dihydroresorufin back into resorufin. File:Vanishing Valentine.webm, solution turn from colorless to red File:Vanishing valentine before shook.JPG, reduced color of the experiment File:Vanishing valentine after shook.JPG, oxidized color of the experiment


Others

;Gatorade Erioglaucine, a food colorant and a redox dye, was found to be an effective substitute for methylene blue in the blue bottle experiment. Since some candies and drinks such as
Gatorade Gatorade is an American brand of sports-themed beverage and food products, built around its signature line of sports drinks. The drink is owned and manufactured by PepsiCo and is distributed in over 80 countries. The beverage was develope ...
contain the dye and a reducing sugar, only sodium hydroxide need be added to turn these food products into a blue bottle solution. ;Purple flask
Thionine Thionine, also known as Lauth's violet, is the salt of a heterocyclic compound. It was firstly synthesised by Charles Lauth. A variety of salts are known including the chloride and acetate, called respectively thionine chloride and thionine ac ...
can be used in the green version of the experiment in combination with copper/iron catalyst to create the purple flask.


Pattern formation

Pattern formation The science of pattern formation deals with the visible, (statistically) orderly outcomes of self-organization and the common principles behind similar patterns in nature. In developmental biology, pattern formation refers to the generation of c ...
is when a solution containing NaOH, glucose, and dye is poured into a
Petri dish A Petri dish (alternatively known as a Petri plate or cell-culture dish) is a shallow transparent lidded dish that biologists use to hold growth medium in which cells can be cultured,R. C. Dubey (2014): ''A Textbook Of Biotechnology For Class- ...
that is open to the atmosphere. This will result in solution changing its structure over a period of time. Structures arise from molecular transport through
diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...
and
chemical kinetics Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a ...
. Patterns formed in the Petri dish can be described as a mosaic pattern; web-like, dynamic spiral, branching, and lines connecting to each others. Changes in pattern formation are not homogeneous and can be affected by several factors. Different types of dye in solution will give the same pattern because of the bond's formation and the dynamics remain the same, this is because the solution has the same colour as the dye. Different amounts of dye can result in density change in the solution and this results in changing of convective motion. Different amounts of dye can bring in different amounts of convention cells which are also formed by different amounts of glucose and oxidized product. This can result in an interesting spatial phenomena. Time can also affect pattern formation. As the time passed, one pattern gradually faded away. Spirals and branches started to disappear and eventually disappeared fully. These facts indicate that
oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
affects the chemical reaction and this plays a fundamental role in the pattern formation. Pattern formation may also form from a chemically driven convective instability. This means that matter is exchanged across the air-reaction mixture interface, due to the fluctuations in the molecular nature of chemical systems. The temperature can affect the formation of pattern. Colder temperature formed a clearer pattern than hot temperature. The shape of the Petri dish also contributed to the pattern formation. File:Pattern Formation from Blue Bottle Experiment in Ice Water Bath.webm, Pattern Formation from Blue Bottle Experiment in Ice Water Bath Time-lapse File:Pattern Formation from Blue Bottle Experiment in Ice Water Bath.jpg, Pattern Formation from Blue Bottle Experiment in Ice Water Bath File:Pattern Formation from Blue Bottle Experiment in Cold Water Bath.webm, Pattern Formation from Blue Bottle Experiment in Cold Water Bath Time-lapse File:Pattern Formation from Blue Bottle Experiment in Cold Water Bath.jpg, Pattern Formation from Blue Bottle Experiment in Cold Water File:Pattern Formation from Blue Bottle Experiment in Room Temperature.webm, Pattern Formation from Blue Bottle Experiment in Room Temperature Time-lapse File:Pattern Formation from Blue Bottle Experiment in Room Temperature.jpg, Pattern Formation from Blue Bottle Experiment in Room Temperature File:Pattern Formation from Blue Bottle Experiment in Warm Water Bath.webm, Pattern Formation from Blue Bottle Experiment in Warm Water Bath Time-lapse File:Pattern Formation from Blue Bottle Experiment in Warm Wate.jpg, Pattern Formation from Blue Bottle Experiment in Warm Water Bath File:Chemical Traffic Light Experiment Pattern Formation In Different Shape Containers.webm, Chemical Traffic Light Experiment Pattern Formation In Different Shape Containers Time-lapse File:Chemical Traffic Light Experiment Pattern Formation In Different Shape Containers.png, Chemical Traffic Light Experiment Pattern Formation In Different Shape Containers A group of researchers of the
University of Glasgow The University of Glasgow (abbreviated as ''Glas.'' in Post-nominal letters, post-nominals; ) is a Public university, public research university in Glasgow, Scotland. Founded by papal bull in , it is the List of oldest universities in continuous ...
named Pons, Batiste and Bees came up with a small conclusion about pattern formation in the methylene blue-glucose system. They came up with a conclusive statement that a similar pattern can be formed in a container with accessible oxygen. This resulting surface tension effect isn't required to produce the instability. Small holes were also found in the lid of container that oxygen can't access resulting in a thin, blue, and lower amount of oxygen. Pattern length and time scale had been explored in one of their experiments due to the variation in viscosity and fluid depth. The experiment reveals that the
wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...
is formed as a pattern starts to form quickly. Then wavelength or pattern can be maintained or oscillate for a while.


References


External links

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