Soap bubble: Difference between revisions

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{{short description|Thin film of soapy water enclosing air}}

[[Image:Bubble brokenchopstick.jpg|300px|thumb|right|A soap bubble]]

[[File:Reflection in a soap bubble edit.jpg|thumb|A soap bubble]]

A '''soap bubble''' is a very thin [[soap film|film]] of [[soap]] water that forms a [[sphere]] with an [[iridescence|iridescent]] [[surface]]. Soap bubbles usually last for only a few moments and then burst either on their own or on contact with another object. They are often used as a children's plaything, but their usage in artistic [[performance]]s shows that they can be fascinating for adults too. Soap bubbles can help to solve complex [[mathematics|mathematical]] problems of [[space]], as they will always find the smallest surface area between [[Point (geometry)|points]] or [[edge]]s.

[[File:Girl blowing bubbles.jpg|thumb|Girl blowing bubbles]]

[[File:Soapbubbles1b.jpg|thumb|Many bubbles make [[foam]]]]

A '''soap bubble''' (commonly referred to as simply a '''bubble''') is an extremely thin [[soap film|film]] of [[soap]] or [[detergent]] and water enclosing air that forms a hollow [[sphere]] with an [[iridescent]] surface. Soap bubbles usually last for only a few seconds before bursting, either on their own or on contact with another object. They are often used for children's enjoyment, but they are also used in artistic [[performance]]s. Assembling many bubbles results in [[foam]].

When light shines onto a bubble it appears to change colour. Unlike those seen in a [[rainbow]], which arise from differential refraction, the colours seen in a soap bubble arise from light [[wave interference]], reflecting off the front and back surfaces of the thin soap film. Depending on the thickness of the film, different colours interfere constructively and destructively.

==Structure==

The bubble's 'skin' consists of a thin layer of water trapped between two layers of molecules, often [[soap]]. This surfactant possesses [[hydrophilic]] heads and [[hydrophobic]] tails. The hydrophilic heads are attracted to the thin water layer and keep the bubble intact. When the hydrophobic tails are agitated, the bubble pops. It may also burst when it hits pointy surfaces.

==Physics Mathematics ==

Soap bubbles are physical examples of the complex [[math]]ematical problem of [[minimal surface]]. They will assume the shape of least [[surface area]] possible containing a given volume. A true minimal surface is more properly illustrated by a [[soap film]], which has equal pressure on both sides, becoming a surface with zero [[mean curvature]]. A soap bubble is a closed soap film: due to the difference in outside and inside pressure, it is a surface of ''constant'' mean curvature.

===Surface tension and shape===

[[Image:Jean-Baptiste Siméon Chardin 022.jpg|thumb|Soap bubbles, [[Jean-Baptiste Siméon Chardin]], 2nd third of 18th century.]]

While it has been known since 1884 that a spherical soap bubble is the least-area way of enclosing a given volume of air (a theorem of [[H. A. Schwarz]]), it was not until 2000 that it was proven that two merged soap bubbles provide the optimum way of enclosing two given volumes of air of different size with the least surface area. This has been dubbed the ''[[double bubble conjecture]]''.<ref>{{ cite journal| last1 = Hutchings | first1 = Michael | first2= Frank |last2 = Morgan| first3=Manuel |last3= Ritoré | first4= Antonio| last4= Ros | date = July 17, 2000 | title = Proof of the double bubble conjecture | journal = Electronic Research Announcements of the American Mathematical Society| volume = 6| issue = 6 |pages = 45–49 | doi = 10.1090/S1079-6762-00-00079-2

A bubble can exist because the surface layer of a liquid (usually water) has a certain [[surface tension]], which causes the layer to behave somewhat like an [[elastic]] sheet. However, a bubble made with a pure liquid alone is not stable and a dissolved [[surfactant]] such as soap is needed to stabilize a bubble. A common misconception is that soap increases the water's surface tension. Actually soap does the exact opposite, decreasing it to approximately one third the surface tension of pure water. Soap does not ''strengthen'' bubbles, it ''stabilizes'' them, via an action known as the [[Marangoni effect]]. As the soap film stretches, the surface concentration of soap decreases, which causes the surface tension to increase. Thus, soap selectively strengthens the weakest parts of the bubble and tends to prevent them from stretching further. In addition, the soap reduces [[evaporation]] so the bubbles last longer, although this effect is relatively small.

| doi-access = free | hdl = 10481/32449 | hdl-access = free }}</ref>

Because of these qualities, soap bubble films have been used in practical problem solving applications. [[Structural engineer]] [[Frei Otto]] used soap bubble films to determine the geometry of a sheet of least surface area that spreads between several points, and translated this geometry into revolutionary [[tension structure|tensile roof structures]].<ref>[https://www.theguardian.com/artanddesign/2004/oct/04/architecture Jonathan Glancey, The Guardian November 28, 2012] {{webarchive|url=https://web.archive.org/web/20170108193633/https://www.theguardian.com/artanddesign/2004/oct/04/architecture |date=January 8, 2017 }}</ref> A famous example is his West German Pavilion at Expo 67 in Montreal.

Their [[Sphere|spherical]] shape is also caused by surface tension. The tension causes the bubble to form a sphere, as a sphere has the smallest possible [[surface area]] for a given [[volume]]. This shape can be visibly distorted by air currents, and hence by blowing. If a bubble is left to sink in still [[air]], however, it remains very nearly spherical, more so for example than the typical cartoon depiction of a [[raindrop]]. When a sinking body has reached its [[terminal velocity]], the [[drag force]] acting on it is equal to its weight, and since a bubble's weight is much smaller in relation to its size than a raindrop's, its shape is distorted much less. (The surface tension opposing the distortion is similar in the two cases: The soap reduces the water's surface tension to approximately one third, but it is effectively doubled since the film has an inner and an outer surface.)

=== Soap bubbles as unconventional computing ===

===Freezing===

{{see also|Unconventional computing}}

Soap bubbles blown into air that is below a [[temperature]] of −15 [[Celsius|°C]] (5 [[Fahrenheit|°F]]) will freeze when they [[Nucleation|touch a surface]]. The air inside will gradually [[diffusion|diffuse]] out, causing the bubble to crumple under its own weight.

The structures that soap films make can not just be enclosed as spheres, but virtually any shape, for example in wire frames. Therefore, many different minimal surfaces can be designed. It is actually sometimes easier to physically make them than to compute them by [[mathematical modelling]]. This is why the soap films can be considered as [[analog computer]]s which can outperform conventional computers, depending on the complexity of the system.<ref>{{Cite journal | doi = 10.1511/2012.96.1| title = The Soap Film: An Analogue Computer| journal = American Scientist| volume = 100| issue = 3| pages = 1| year = 2012| last1 = Isenberg | first1 = Cyril }}</ref><ref>{{Cite journal | doi = 10.1511/2012.96.1| title = The Soap Film: An Analogue Computer| journal = American Scientist| volume = 64| issue = 3| pages = 514–518| year = 1976| last1 = Isenberg | first1 = Cyril | bibcode = 1976AmSci..64..514I}}</ref><ref>{{Cite journal | doi = 10.1511/2012.96.1| title = Soap Film Letters| journal = American Scientist| volume = 100| issue = January–February| pages = 1| year = 1977| last1 = Taylor | first1 = Jean E. }}</ref>

== Physics ==

At temperatures below about −25 °C (−13 °F), bubbles will freeze in the air and may shatter when hitting the ground. When, at this low temperature, a bubble is blown with warm breath, the bubble will freeze to an almost perfect sphere at first, but when the warm air cools and thus is reduced in volume there will be a partial collapse of the bubble. A bubble, blown successfully at this low temperature, will always be rather small in size: it will freeze quickly and continuing to blow will shatter the bubble.

{{broader|Bubble (physics)}}

=== Merging ===

[[File:Ggb in soap bubble 1.jpg|thumb|Soap bubbles can easily merge]]

[[File:Soap bubbles being formed by a bubble wand - slow motion - 2022 July 28.webm|thumb|Slow motion video of soap bubbles being formed by a bubble wand]]

When two bubbles merge, they adopt a shape which makes the sum of their surface areas as small as possible, compatible with the volume of air each bubble encloses. If the bubbles are of equal size, their common wall is flat. If they are not the same size, their common wall bulges into the larger bubble, since the smaller one has a higher internal [[pressure]] than the larger one, as predicted by the [[Young–Laplace equation]].

At a point where three or more bubbles meet, they sort themselves out so that only three bubble walls meet along a line. Since the surface tension is the same in each of the three surfaces, the three angles between them must be equal to 120°. Only four bubble walls can meet at a point, with the lines where triplets of bubble walls meet separated by cos⁻¹(−1/3) ≈ 109.47°. All these rules, known as [[Plateau's laws]], determine how a [[foam]] is built from bubbles.

[[Image:Soap Bubble - foliage background - iridescent colours - Traquair 040801.jpg|thumb|right|Soap bubbles can easily merge]]

===Merging Stability ===

The longevity of a soap bubble is limited by the ease of rupture of the very thin layer of water which constitutes its surface, namely a [[micrometre|micrometer]]-thick [[soap film]].

When two bubbles merge, the same physical principles apply, and the bubbles will adopt the dookie shape with the smallest possible dookie surface area. Their common wall will bulge into the larger bubble, as smaller bubbles have a higher internal [[pressure]]. If the bubbles are of equal size, the wall will be flat.

It is thus sensitive to :

* Drainage within the soap film: water falls down due to gravity. This can be slowed by increasing the water viscosity, for instance by adding glycerol. Still, there is an ultimate height limit, which is the [[capillary length]], very high for soap bubbles: around 13 feet (4 meters). In principle, there is no limit in the length it can reach.

* [[Evaporation]]: This can be slowed by blowing bubbles in a wet atmosphere, or by adding some sugar to the water.

* Dirt and fat: When the bubble touches an object, it usually ruptures the soap film. This can be prevented by wetting these surfaces with water (preferably containing some soap).

After experiments, researchers found that a solution containing:

At a point where two or more bubbles meet, they sort themselves out so that only three bubble walls meet along a line. Since the surface tension is the same in each of the three surfaces, the three angles between them must be equal angles of 120°. This is the most efficient choice, again, which is also the reason why the cells of a [[beehive (beekeeping)|beehive]] use the same 120° angle, thus forming [[hexagon]]s. Only four bubble walls can meet at a point, with the lines where triplets of bubble walls meet separated by cos^&minus;1(&minus;1/3) ≈ 109.47°.

* 85.9 % water

===Interference and reflection===

* 10 % [[glycerol]]

[[Image:thinfilmbubble.jpg|275px|thumb|right|Thin film interference in a soap bubble. Notice the golden yellow colour near the top where the film is thin and a few even thinner black spots.]]

* 4 % [[dishwashing liquid]]

* 0.1 % [[guar gum]]

gave the longest lasting results as it minimised the [[Marangoni Effect]].<ref>[https://www.newscientist.com/article/2338803-whats-the-best-recipe-for-bubble-mixture-scientists-have-the-answer/ New Scientist: What’s the best recipe for bubble mixture? Scientists have the answer 22 September 2022 By Chris Simms]</ref>

The iridescent colours of soap bubbles are caused by [[interference|interfering]] light waves and are determined by the thickness of the film. They are '''not''' the same as rainbow colours but are the same as the colours in an oil slick on a wet road.

=== Wetting ===

As light impinges on the film, some of it is [[Reflection (physics)|reflected]] off the outer surface while some of it enters the film and reemerges after being reflected back and forth between the two surfaces. The total reflection observed is determined by the interference of all these reflections. Since each traversal of the film incurs a [[phase shift]] proportional to the thickness of the film and inversely proportional to the wavelength, the result of the interference depends on these two quantities. Thus, at a given thickness, interference is constructive for some wavelengths and destructive for others, so that [[white#White light|white light]] impinging on the film is reflected with a [[hue]] that changes with thickness.

When a soap bubble is in contact with a solid or a liquid surface [[wetting]] is observed. On a solid surface, the [[contact angle]] of the bubble depends on the [[surface energy]] of the solid.<ref>{{Cite journal | doi=10.1016/j.jcis.2009.05.062| pmid=19541324| title=Contact angle of a hemispherical bubble: An analytical approach| journal=Journal of Colloid and Interface Science| volume=338| issue=1| pages=193–200| year=2009| last1=Teixeira| first1=M.A.C.| last2=Teixeira| first2=P.I.C.| bibcode=2009JCIS..338..193T| s2cid=205804300| url=http://centaur.reading.ac.uk/29242/1/contact_rev3.pdf}}</ref><ref>{{Cite journal |doi = 10.1063/1.4812710|title = Wetting of soap bubbles on hydrophilic, hydrophobic, and superhydrophobic surfaces|journal = Applied Physics Letters|volume = 102|issue = 25|article-number = 254103|year = 2013|last1 = Arscott|first1 = Steve|bibcode = 2013ApPhL.102y4103A|arxiv = 1303.6414|s2cid = 118645574}}</ref> A soap bubble has a larger contact angle on a solid surface displaying [[ultrahydrophobicity]] than on a hydrophilic surface – see [[Wetting]]. On a liquid surface, the contact angle of the soap bubble depends on its size - smaller bubbles have lower contact angles.<ref>M.A.C. Teixeira, S. Arscott, S.J. Cox and P.I.C. Teixeira, Langmuir 31, 13708 (2015).[http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.5b03970]</ref><ref>{{cite web |url=https://ciencias.ulisboa.pt/pt/noticia/08-02-2016/o-despertar-da-bolha |title=O despertar da bolha |access-date=2016-02-09 |url-status=live |archive-url=https://web.archive.org/web/20160212130252/http://ciencias.ulisboa.pt/pt/noticia/08-02-2016/o-despertar-da-bolha |archive-date=2016-02-12 }}</ref>

A change in colour can be observed while the bubble is thinning due to evaporation. Thicker walls cancel out red (longer) wavelengths, thus causing a blue-green reflection. Later, thinner walls will cancel out yellow (leaving blue light), then green (leaving [[magenta]]), then blue (leaving a golden yellow). Finally, when the bubble's wall becomes much thinner than the wavelength of visible light, all the waves in the visible region cancel each other out and no reflection is visible at all. When this state is observed, the wall is thinner than about 25 [[nanometre]]s, and is probably about to pop. This phenomenon is very useful when making or manipulating bubbles as it gives an indication of the bubble's fragility.

<gallery mode=packed heights=180>

Interference effects also depend upon the angle at which the light strikes the film, an effect called ''[[iridescence]]''. So, even if the wall of the bubble were of uniform thickness, one would still see variations of color due to curvature and/or movement. However, the thickness of the wall is continuously changing as gravity pulls the liquid downwards, so bands of colours that move downwards can usually also be observed.

File:Bubble on an ultrahydrophobic surface.jpg|A soap bubble wetting an ultrahydrophobic surface

File:Bubble on a liquid surface.jpg|A soap bubble wetting a liquid surface

<gallery>

Image:Reflection_from_a_bubble1.png|In the diagram above a ray of light hits the surface at point X. Some of the light is reflected, but some travels through the bubble wall and is reflected at the other side. <p> <p>When light directed from low index material strikes a high index material (air to film), there is a 180 degree phase shift just from the reflection (a "hard" reflection). So the film thicknesses discussed for red and blue light in the panels to the right are incorrect by half a wavelength.

Image:Bubble_interference_(red).png|In this diagram we look at two rays of red light (rays 1 and 2). Both rays are split as before and follow two possible paths, but we are interested only in the paths that are represented by the solid lines. Consider the ray emerging at Y. It consists of two rays on top of one another: the bit that went through the bubble wall for ray 1 and the bit that was reflected off the outer wall of ray 2. Ray one has travelled XOY further than ray 2. Since XOY happens to correspond to an integer multiple of the wavelength of red light, the two rays are in phase (the humps and troughs are together).

Image:Bubble_interference_(blue).png|This is similar to the previous diagram except the wavelength is different. This time XOY is not an integer multiple of the wavelength of blue light and so ray 1 and 2 arrive at y out of step. The troughs of ray 1 line up with the humps of ray 2 and the two rays cancel each other out. The overall effect is that no blue light will be reflected for this thickness of bubble.

Image:colours reflected from a thin water film depending on thickness and angle of incidence.png|This computed image shows the colours reflected by a thin film of water illuminated by unpolarized white light. The radius is proportional to the thickness of the film, and the polar angle is the angle of incidence.

</gallery>

=== Floatation ===

==Mathematical properties==

The gas inside a bubble is less dense than air because it is mostly water vapor. Water vapor is a gas that is formed when water molecules evaporate. When water molecules evaporate, they escape from the liquid state and enter the gas state. In the gas state, water molecules are further apart than they are in the liquid state. This is because water molecules are attracted to each other. When they evaporate, they break away from these attractions and move further apart.

[[Image:Soapbubbles1b.jpg|thumb|right|Bubbles in a washing-up bowl]]

Soap bubbles are also physical illustrations of the problem of [[minimal surface]]s, a complex mathematical problem. For example, while it has been known since [[1884]] that a spherical soap bubble is the least-area way of enclosing a given volume of air (a theorem of [[H. A. Schwarz]]), it was only recently proved in the year [[2000]] that two merged soap bubbles provide the optimum way of enclosing two given volumes of air with the least surface area. This has been termed the ''[[double bubble theorem]]''.

The further apart water molecules are, the less dense they are. This is why water vapor is less dense than air. The gas inside a bubble is mostly water vapor, so it is also less dense than air.

Soap films seek to minimise their surface area, that is, to minimise their surface energy. The optimum shape for an isolated bubble is thus a sphere. Many bubbles packed together in a foam have much more complicated shapes. See [[Weaire-Phelan structure]] for a discussion of this (called the [[Kelvin problem]]), and [[Plateau's laws]] for a discussion of the structure of the films.

The density of a gas can also be affected by its temperature. As the temperature of a gas increases, the molecules of the gas move faster. This causes them to spread out and become less dense. The opposite is also true. As the temperature of a gas decreases, the molecules of the gas move slower. This causes them to bunch together and become more dense.

==Coloured bubbles==

[[Image:Zubble.JPG|thumb|right|Zubbles]]

Adding coloured [[dye]] to bubble mixtures fails to produce coloured bubbles, because the dye attaches to the water molecules as opposed to the surfactant. Hence, a colourless bubble forms with the dye falling to a point at the base. Dye [[chemist]] [[Ram Sabnis|Dr. Ram Sabnis]], has developed a [[lactone]] dye that sticks to the surfactants, thus enabling brightly coloured bubbles to be formed. An example of this dye is [[crystal violet lactone]].

The temperature of the gas inside a bubble is affected by the temperature of the water around it. The warmer the water, the warmer the gas inside the bubble. This means that the gas inside a bubble will be less dense if the water is warm than if the water is cold.

These new bubble mixtures are currently only being sold in the [[USA]] under the trade name ''[[Zubbles]]''.

==Recreation==

[[Image:Food coloring.jpg|thumb|250px|[[Food coloring]] spreading on a soap bubble.]]

==How= toUse makein soap bubblesplay == =

The easiest ways are to use commercially produced soap bubble fluid (marketed as a toy) or to simply put some dishwashing soap in water. However, this latter might not work as well as expected, and there are several tricks to improve the soap suds formula:

Soap bubbles have been used as entertainment for at least 400 years, as evidenced by 17th-century Flemish paintings showing children blowing bubbles with clay pipes. The London-based firm [[Pears (soap)|A. & F. Pears]] created a famous advertising campaign for its soaps in 1886 using a painting by John Everett Millais of a child playing with bubbles. The Chicago company Chemtoy began selling bubble solution in the 1940s, and bubble solution has been popular with children ever since. According to one industry estimate, retailers sell around 200 million bottles annually. [[Dishwashing liquid]] with water and additional ingredients such as [[Glycerol|glycerin]] and [[sugar]] is used as a popular alternative to a ready made bubble solution.<ref>{{cite web | url=https://www.scientificamerican.com/article/blow-the-biggest-bubbles/ | title=Blow the Biggest Bubbles | website=[[Scientific American]] }}</ref>

===Additives===

* Something to reduce the water's surface tension, such as liquid soap or baby shampoo. These may work better the more pure (devoid of [[perfume]] or other additives) the soap is, or perhaps with more expensive soaps.

* Something to thicken the water. Most commonly used is [[glycerin]] (available at the [[pharmacy]]), which makes the bubbles more colourful, too. [[Sugar]], icing sugar or [[corn syrup]] have similar effects. It may be advantageous to dissolve the sugar in hot water. However, the soap sud can also be too thick and heavy, so it is important not to add too much of these thickening substances.

*[[Distilled water]]. As tap water contains [[calcium]] ions, and these bind the soap, distilled water works better.

<gallery mode=packed>

===Procedure===

File:Bhutan, "Prayer Bubbles" - Flickr - babasteve.jpg|Blowing bubbles through a small wand

* Leaving the soap sud in an open container overnight makes it thicker, too. But again, if the solution becomes too heavy it will be harder to make soap bubbles.

File:Girl Blowing Bubbles.jpg|A woman creating bubbles with a long soap bubble wand

* Bubbles or [[foam]] on the surface of the soap sud should be avoided by stirring gently, skimming them away or simply waiting until they are gone.

File:Adriaen Hanneman Two Boys Blowing Bubbles.JPG|[[Adriaen Hanneman]], ''Two Boys Blowing Bubbles'' ({{circa|1630}})

* How easy it is to make soap bubbles depends on a vast number of factors. Every soap is different, and environmental conditions influence performance, too. For example, dusty air is unfavourable, and so is wind. Also, the more [[humid]] the air is, the better, which means making soap bubbles is easier on rainy days. Altogether, the best procedure for finding the perfect solution is the [[trial and error]] method.

File:Jean-Baptiste Siméon Chardin 022.jpg|[[Jean-Baptiste-Siméon Chardin]], ''[[Soap Bubbles (painting)|Soap Bubbles]]'' ({{circa|1734}})

</gallery>

==History= ofColored bubbles as playthings===

[[ImageFile:Soapbubbles-SteveEFMacro Photography of a soap bubble.jpg|thumb|left|ThisA girlsingle islight usingsoap abubble plasticphotograph yellowtaken blower.under macro photography]]

17th century Flemish paintings show children blowing with clay pipes. This means that bubbles as playthings are at least 400 years old. The London based firm of A. & F. Pears created a famous advertisement campaign for its soaps in [[1886]] using a painting by [[Millais]] of a child playing with bubbles. A Chicago company called Chemtoy began selling bubble solution in the 1940s, and they have captivated children ever since. According to one industry estimate, retailers sell around 200 million bottles annually, perhaps more than any other toy.

A bubble is made of transparent water enclosing transparent air. However, the [[soap film]] is as thin as the visible light [[wavelength]], resulting in [[optical interference]]. This creates [[iridescence]] which, together with the bubble's spherical shape and fragility, contributes to its magical effect on children and adults alike. Each colour is the result of varying thicknesses of soap bubble film. [[Tom Noddy]] (who featured in the second episode of [[Marcus du Sautoy]]'s ''[[The Code (2011 TV series)|The Code]]'') gave the analogy of looking at a [[contour line|contour]] map of the bubbles' surface. However, it has become a challenge to produce artificially coloured bubbles.

===Bubble blowers===

The easiest way is to use either a normal [[Drinking straw|straw]] or one of the plastic blowers (bubble wands) that are sold with most commercial soap bubble solutions. However, as the blower's [[diameter]] determines the size of the soap bubble, it might be necessary to build a blower. Bubble wands have been around since the 1920's.

Byron, Melody & Enoch Swetland invented a patented non-toxic bubble (Tekno Bubbles)<ref>{{cite web |author=Mary Bellis |url=http://inventors.about.com/library/weekly/aa061500a.htm |title=Interview with Byron and Melody Swetland - The Inventors of Tekno Bubbles |publisher=Inventors.about.com |date=1999-10-05 |access-date=2013-10-04 |url-status=dead |archive-url=https://archive.today/20130704191253/http://inventors.about.com/library/weekly/aa061500a.htm |archive-date=2013-07-04 }}</ref> that glow under UV lighting. These bubbles look like ordinary high quality "clear" bubbles under normal lighting, but glow when exposed to true UV light. The brighter the UV lighting, the brighter they glow. The family sold them worldwide, but has since sold their company.

Most closed-ring structures will work. A blower can be made by bending a wire into a loop with a handle, where the wire should be thick enough so the ring remains stiff. It can be improved by wrapping a [[yarn|thread]] or [[bandage]]s around the wire so the soap water can stick better to the ring.

[[File:Triple layer soap bubble.jpg|thumb|A single soap bubble displaying three layers]]

Klutz Press popularized a "giant bubble" blower, invented by a man named David Stein, which used a cloth loop attached to a plastic wand, with a slide permitting the loop to be gently opened or closed. Klutz sells bubble books which offer how-tos and fun ideas, usually with a ready-to-use bubble loop.

Adding coloured [[dye]] to bubble mixtures fails to produce coloured bubbles, because the dye attaches to the water molecules as opposed to the surfactant. Therefore, a colourless bubble forms with the dye falling to a point at the base. Dye [[chemist]] [[Ram Sabnis|Dr. Ram Sabnis]] has developed a [[lactone]] dye that sticks to the surfactants, enabling brightly coloured bubbles to be formed. [[Crystal violet lactone]] is an example. Another man named Tim Kehoe invented a coloured bubble which loses its colour when exposed to pressure or oxygen, which he is now marketing online as [[Zubbles]], which are non-toxic and non-staining. In 2010, Japanese astronaut [[Naoko Yamazaki]] demonstrated that it is possible to create coloured bubbles in [[microgravity]]. The reason is that the water molecules are spread evenly around the bubble in the low-gravity environment.

=== Freezing ===

Bubbles can be blown by using a bubble pipe, which is made of plastic and usually takes the shape of a [[smoking pipe]], sometimes containing multiple bowls. The bubble solution is poured into the bowl of the pipe; when someone blows into the mouthpiece, bubbles rise from the bowl.

[[File:Frozen soap bubble behind fir twigs (Unsplash BojuZpqw4zM).jpg|thumb|A soap bubble freezing on a [[fir]] branch]]

If soap bubbles are blown into air that is below a [[temperature]] of {{convert|-15|C|F|lk=on}}, they will freeze when they [[Nucleation|touch a surface]]. The air inside will gradually [[diffusion|diffuse]] out, causing the bubble to crumble under its own weight. At temperatures below about {{convert|-25|C|F}}, bubbles will freeze in the air and may shatter when hitting the ground. When a bubble is blown with warm air, the bubble will freeze to an almost perfect sphere at first, but when the warm air cools, and a reduction in volume occurs, there will be a partial collapse of the bubble. A bubble, created successfully at this low temperature, will always be rather small; it will freeze quickly and will shatter if increased further.<ref>Hope Thurston Carter: [http://hopecarter.photoshelter.com/gallery/Frozen-Frosted-Fun/G0000C2ixRgR2ecg/ Frozen Frosted Fun] {{webarchive|url=https://web.archive.org/web/20160215083224/http://hopecarter.photoshelter.com/gallery/Frozen-Frosted-Fun/G0000C2ixRgR2ecg |date=2016-02-15 }} hopecarter.photoshelter.com, Michigan, USA, 2014, retrieved 25 January 2017. – Photo catalogue.</ref>

Freezing of small soap bubbles happens within 2 seconds after setting on snow (at air temperature around –10...–14&nbsp;°C).<!--http://www.accuweather.com/de/de/regensburg/93047/january-weather/167556 recorded –8/–14°C for 23 January 2017, the pictures seem to be taken during nighttime and outside of town. --><ref>pilleuspulcher: [https://plus.google.com/+pilleuspulcher/posts/3ZbXqEr5iYc Freezing soap bubbles on snow] {{webarchive|url=https://web.archive.org/web/20170202095553/https://plus.google.com/+pilleuspulcher/posts/3ZbXqEr5iYc |date=2017-02-02 }} google+, Regensburg, Germany, 23 January 2017, retrieved 25 January 2017. – Photos, description in German.</ref>

===Sample formulae=Art ==

[[File:Professional bubble.jpg|thumb|Professional 'bubbleologist' at the 2009 [[Strawberry Fair]] in [[Cambridge]], UK]]

#General purpose formula:

[[File:Szappanbuborék - Alex, Deák tér (1).JPG|thumb|Soap bubbles in downtown Budapest]]

#*²/₃ cup dishwashing [[detergent]]

Soap bubble [[performance]]s combine [[entertainment]] with artistic achievement. They require a high degree of skill.{{citation needed|date=January 2013}} Some performers use common commercially available bubble liquids while others compose their own solutions. Some artists create giant bubbles or tubes, often enveloping objects or even humans. Others manage to create bubbles forming cubes, tetrahedra and other shapes and forms. Bubbles are sometimes handled with bare hands. To add to the visual experience, they are sometimes filled with [[smoke]], vapour or [[helium]] and combined with [[laser]] lights or fire. Soap bubbles can be filled with a flammable gas such as [[natural gas]] and then ignited.

#*1 [[gallon]] water

#*35 ml [[glycerin]]

#Another general purpose formula:

#*100 g [[sugar]]

#* 40 ml [[salt]]

#*1.4 l water ([[distilled water]] is better)

#*150 ml dish washing detergent

#*12 ml glycerin

#Yet another general purpose formula:

#*1 part of washing-up detergent

#*2 parts of glycerin

#*3 parts of water

#For long living bubbles:

#*¹/₃ cup commercial bubble solution

#*¹/₃ cup water

#*¹/₃ cup glycerin

#For no-tears soap bubbles:

#*60 ml baby [[shampoo]]

#*200 ml water

#*45 ml [[corn syrup]]

#Already Hand made by experts cost is $25.00 with color

Professional bubble artists include [[Tom Noddy]], [[Fan Yang (artist)|Fan Yang]] and [[The Amazing Bubble Man]].

==Performance art==

Soap bubble [[performance]]s combine [[entertainment]] with artistic achievement. They require a high degree of skill as well as perfect bubble suds. Some artists create giant bubbles or tubes, often enveloping objects or even humans. Others manage to create bubbles forming cubes, tetrahedra and other shapes or sculptures. Bubbles are often handled with bare hands. One such performer is Tom Noddy[http://www.tomnoddy.com/]. To add to the visual experience, they are sometimes filled with [[smoke]] or [[helium]] and combined with [[laser]] lights or fire. Soap bubbles can be filled with a flammable gas such as [[natural gas]] and then ignited. Of course, this destroys the bubble.

==See alsoEducation ==

Bubbles can be effectively used to teach and explore a wide variety of concepts to even young children. Flexibility, colour formation, reflective or mirrored surfaces, concave and convex surfaces, transparency, a variety of shapes (circle, square, triangle, sphere, cube, tetrahedron, hexagon), elastic properties, and comparative sizing, as well as the more esoteric properties of bubbles listed on this page. Bubbles are useful in teaching concepts starting from 2 years old and into college years. A Swiss university professor, Dr. Natalie Hartzell, has theorized that the usage of artificial bubbles for entertainment purposes of young children has shown a positive effect in the region of the child's brain that controls motor skills and is responsible for coordination with children exposed to bubbles at a young age showing measurably better motion skills than those who were not.<ref>{{Cite journal | doi = 10.2307/1970949| jstor = 1970949| title = The Structure of Singularities in Soap-Bubble-Like and Soap-Film-Like Minimal Surfaces| journal = The Annals of Mathematics| volume = 103| issue = 3| pages = 489–539| year = 1976| last1 = Taylor | first1 = J. E. }}</ref>

*[[Joseph Plateau]], formulator of [[Plateau's laws]] on the geometry of intersecting soap films, and [[Plateau's problem]].

*The French writer [[Alfred Jarry]] was highly impressed by physicist [[C.V. Boys]]'s ''Soap-Bubbles: Their Colours and the Forces that Mould Them'' and incorporated parts of it into his eccentric novel ''Exploits and Opinions of Dr. Faustroll, pataphysician'', written in [[1898]]. The book describes the exploits and teachings of a sort of philosopher who, born at age 63, travels through [[Paris]] in a sieve and subscribes to the tenets of [['Pataphysics|'pataphysics]], which deals with "the [[laws]] which govern exceptions and will explain the [[universe]] supplementary to this one". In 'pataphysics, every event in the universe is accepted as an extraordinary event.

*[[Zubbles]], colored bubbles.

*[[Antibubble]]

==References See also ==

* [[Antibubble]]

{{Commons|Soap bubble}}

* [[Bubble pipe]]

* [[Foam]]

* [[Joseph Plateau]]

* [[Stretched grid method]]

* [[Tom Noddy]]

* [[The Amazing Bubble Man]]

* [[Weaire–Phelan structure]]

== References ==

{{Reflist|30em}}

== Further reading ==

* Oprea, John (2000). ''The Mathematics of Soap Films&nbsp;– Explorations with Maple''. American Mathematical Society (1st ed.). {{ISBN|0-8218-2118-0}}

* Boys, C. V. (1890) ''Soap-Bubbles and the Forces that Mould Them''; (Dover reprint) {{ISBN|0-486-20542-8}}. Classic Victorian exposition, based on a series of lectures originally delivered "before a juvenile audience".

* [[Cyril Isenberg|Isenberg, Cyril]] (1992) ''The Science of Soap Films and Soap Bubbles ''; (Dover) {{ISBN|0-486-26960-4}}.

* Noddy, Tom (1982) "Tom Noddy's Bubble Magic" Pioneer bubble performer's explanations created the modern performance art.

* Stein, David (2005) "How to Make Monstrous, Huge, Unbelievably Big Bubbles"; (Klutz) Formerly "The Unbelievable Bubble Book" (1987) it started the giant bubble sport. {{ISBN|978-1-57054-257-2}}

== External links ==

{{Commons}}

* [http://www.javierurbina.es International Awarded Bubble Show]

* [http://www.fineartphotography.in Gallery of Macro Photographs of bubbles to create photographic art work]

* [http://www.videophysics.com Videos of Bubble and Droplet Interactions]

* [http://www.exploratorium.edu/ronh/bubbles/bubbles.html A more detailed scientific explanation]

* [http://www.ugrpepbou.es/~ritore/bubble/bubble.htm The proofcom paperPerformances onwith thebubbles Doubleand Bubblegiant Theorembubbles]

* A book about soap bubbles and mathematics: Oprea, John (2000). ''The Mathematics of Soap Films &ndash; Explorations with Maple''. American Mathematical Society (1st ed.). ISBN 0-8218-2118-0

* Boys, C. V. (1890) ''Soap-Bubbles and the Forces that Mould Them''; (Dover reprint) ISBN 0-486-20542-8. Classic Victorian exposition, based on a series of lectures originally delivered "before a juvenile audience".

* Isenberg, Cyril (1992) ''The Science of Soap Films and Soap Bubbles ''; (Dover) ISBN 0-486-26960-4.

{{Foam scales and properties}}

==External links==

{{Patterns in nature}}

* [http://www.bubbleblowers.com/index.html The Bubble Blower Museum], which has photographs and information about bubble blowers from the late 1800s to the present day.

* [http://www.soapbubbler.com SoapBubbler.com], is a non-commercial site dedicated to soap bubble creativity, education, play and performance. It has videos, biographies of bubble performance artists and links.

{{Authority control}}

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[[Category:Fluid dynamics]]

[[Category:Minimal surfaces]]

[[Category:ToysBubbles (physics)]]

[[Category:Physical activity and dexterity toys]]

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