What is Soap: Definition and 103 Discussions

Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are used as thickeners, components of some lubricants, and precursors to catalysts.
When used for cleaning, soap solubilizes particles and grime, which can then be separated from the article being cleaned. In hand washing, as a surfactant, when lathered with a little water, soap kills microorganisms by disorganizing their membrane lipid bilayer and denaturing their proteins. It also emulsifies oils, enabling them to be carried away by running water.Soap is created by mixing fats and oils with a base, as opposed to detergent which is created by combining chemical compounds in a mixer.
Humans have used soap for millennia. Evidence exists of the production of soap-like materials in around 2800 BC in ancient Babylon.

View More On Wikipedia.org
Recent contents Top users
  1. E

    What can I use to make clear dish soap thicker?

    Hello this is my first post to this forum though I've lurked before. I want to paint with something 100% clear and quite viscous. I added food coloring to transparent dish soap and that is so far the best solution to a clear paint body, but I want to make it thicker. I found a list of common...
  2. C

    Alka-Seltzer + Soap reaction rate

    Hello, I have seen that adding dish soap to water and then dissolving Alka-Seltzer in the solution causes the reaction rate to slow. Does anybody have any idea as to why this happens?
  3. B

    Light Waves, Color, and Soap Bubbles

    Homework Statement A soap bubble is floating in the air. The wall of the bubble has an index of refraction of n = 1.33. It is observed that red and violet light are reflected from the surface of the bubble, but no green light is reflected. Compute the minimum thickness of the bubble...
  4. E

    Which Soap Deal Offers Better Value?

    2, 120 gram bars of soap for $2 or... 2, 90 gram bars of soap for $1.50 Can someone explain the method to figure it out so I can properly compare grocery flyer deals in the future? thank you for any help!
  5. M

    Diameter of a soap bubble increases when it is charged

    "Diameter of a soap bubble increases when it is charged." why?
  6. N

    Exploding Soap Bubbles: A question of gasses.

    So we're considering adding some soap bubbles to a fire-dancing show. Why? Because soap bubbles are awesome! But you know what's even _more_ awesome? That's right! EXPLODING SOAP BUBBLES! OK, so we don't really want them to explode (well, _I_ do, but apparently democracy rules), but...
  7. T

    What Determines the Minimum Thickness of a Soap Bubble for Colorful Reflections?

    Homework Statement A soap bubble of refractive index 1.33 is illuminated by white light perpendicular to its surface and viewed normal to its surface. What is the minimum thickness of the bubble for which brightly-coloured reflected light would be seen?Homework Equations \lambda=4ntThe Attempt...
  8. P

    Soap Bubble Pressure: Why Does It Decrease?

    if air is pushed inside a soap bubble then why does the pressure decrease ?
  9. M

    How does the saponification process actually create soap?

    By what process does this actually happen? On wikipedia they show this reaction? 2 NaOH + CO2 → Na2CO3 + H2O My chemistry teacher described it as a process where Process 2 NaOH + CO2 → NaHCO3 + (something else to balance equation not sure) then NaHCO3 + CO2 → Na2CO3 + H2O...
  10. Mueiz

    Does the Relativistic Speed of Soap Bubbles Affect Their Shape?

    It is well known that the shape of soap bubbles is spherical because of the fact that a sphere is the least-area way of enclosing a given volume . If we look to a soap bubble from a frame of reference that move at relativistic speed relative to the bubbles, then ,as a result of length...
  11. N

    Try Soap-Free Bathing: Richard's Experiences | Free the Animal

    Richard Nikoley at Free the Animal has been experimenting with basically a soap-free lifestyle for 18 months now (according to a recent update) and reported his experience (six months in): http://freetheanimal.com/2009/12/paleo-i-dont-care-i-like-no-soap-no-shampoo.html Me, I've been doing...
  12. P

    Reaction of dish soap and bleach

    today I was cleaning out my fiances hamster cage, we had a hamster in there before, and long story short, we had to return for what appeared to be an illness. So, needless to say, I wanted to clean it really well. I first rinsed it with water, then dumped out the water, poured in some...
  13. lisab

    Hand Washing Question: Glycerin Soap

    I've read that when washing one's hands, the primary mechanism by which the hands become clean is mechanical. That is, organisms are removed from your hands by rubbing and rinsing. But I believe that soap itself does have some antimicrobial action. I assume that glycerin soap and regular...
  14. P

    How can entropy explain formation of soap bubbles

    I've taken basic college physics and chemistry courses where I learned about entropy and thermodynamics, and I can tell you that I don't know that much :) That's my background. I understand that entropy is a description of 'randomness' and possible 'states'. When I wash my hands with soap...
  15. W

    Titrating Biodiesel for soap content

    Good afternoon people I wish to titrate biodiesel for soap content.There are video's on you tube describing how. I have all the bits required including bromophenol blue and hydrochloric acid. The acid is at 38% and I need a solution of .01N HCl. Well its a long time since I was at school...
  16. R

    Density of a Bar of Soap/ buoyancy

    Homework Statement A rectangular bar of soap floats with 3.5 cm extending below the water surface and 1.5 cm above. what is its density? Homework Equations p(rho)=m/v The Attempt at a Solution I don't know how to compute the volume since we are given only two lengths. Athough...
  17. M

    What is the equation for the pressure of a coalesced soap bubble?

    Homework Statement Two spherical soap bubbles of radii a[1] and a[2] are made to coalesce. Show that when the temperature of the gas in the resulting soap bubble has returned to its initial values, r of the bubble is given by p*r^3+4*\gamma*r^2=p(a[1]^3+a[2]^3)+4\gamma(a[1]^2+a[2]^2) where p...
  18. O

    Soap Bubble and surface tension

    I read to today that soap bubbles explodes due to surface tension regardless of other forces experienced on the bubble. how does surface tension does that? does it "drive" the bubble to go larger until it explodes? Thanks, Omri
  19. P

    Optics: Soap Film and Other Things

    I understand the idea behind the optical interference that produces colors on thin films but have never figured out the reason that the films have to by 'thin'. What is the lack of similarity that I am missing between a film and a somewhat thick sheet of glass or something that makes these...
  20. L

    Uncovering the Mystery of Scented Soap: The Science Behind the Short-Lived Aroma

    OK, I never worried or thought on this till yesterday, and I would like an answer if someone knows. When you open a new brand name bar of soap, by the end of the day, the whole bathroom smells like that soap. Is there an enzyme applied to the outside to make it do this? Because it really...
  21. V

    How is development of ash and oxidation of oils in cold process soap related?

    I posted this on thedishforum: On the German soapmaking forum, there are several posts noting that there seems to be a correlation between ash and oxidation of oils. Can you speak to the presence of ash and soap going rancid? And got this reply: Yes, I could see this being an accurate...
  22. V

    Does soda ash appearing on soap mean that oxidation of oils is about to occur?

    On the German soapmaking forum, there are several posts noting that the presence of ash and the oxidation of oils(rancidity) often go together. When the ash appears in small amounts, I have not noticed any oxidation. When the ash develops over much of the surface of the soap bars, the soap...
  23. V

    Why and how does soda ash appear while soap is curing?

    Ash (sodium carbonate) sometimes appears on soap while it is in the mold, or while it is curing. It is supposed that the alkali in the soap absorbs the carbon dioxide in the air, forming sodiaum carbonate/soda ash on the soap. The ash appears inconsistently. It can appear on only part of...
  24. S

    Soap film having index of refraction

    What is the minimum (non-zero) thickness of a soap film having index of refraction 1.46, with air on both sides, that transmits virtually 100% of 500 nm light incident along the normal? a. 345 nm. b. 86 nm. c. Any thickness transmits 100%. d. 172 nm. I used...
  25. C

    Thin Film Interference in a Soap Bubble

    Homework Statement Question: A soap bubble of index of refraction 1.48 strongly reflects both the red and the green components of white light. What film thickness allows this to happen? (In air, the wavelength of red light is 716 nm, of green light 511.429 nm.) n = 1.48 \lambda(r) =...
  26. Greg Bernhardt

    Pictures show soap bubble bursting

    Super slow motion photos of a soap bubble bursting. I'm impressed! http://www.dailymail.co.uk/news/article-1199149/Super-slow-motion-pictures-soap-bubble-bursting-stunning-detail.html
  27. M

    Exploring the Possibilities: Could an Ant Walk on a Soap Bubble?

    Could a tiny sugar ant walk on a soap bubble? Would the bubble burst? Would the ant be able to locomote along the surface or would it get stuck?
  28. R

    Solve Visible Wavelengths in Reflected Light from Soap Film w/ n=1.90

    Homework Statement A soap film has an index of refraction n = 1.90. The film is viewed in reflected light. (a) At a spot where the film thickness is 910.0 nm, which visible wavelengths are missing in the reflected light? (Give the three wavelengths which correspond to the lowest such m...
  29. A

    How Does Angle of Incidence Affect Color Reflection in Soap Films?

    A thin soap film (n=1.318) suspended in air has a uniform thickness. When white light strikes the film at normal incidence, violet light (412 nm) is constructively reflected. At what angle of incidence will green light (564 nm) be most strongly reflected? Assume that the film as the minimum...
  30. MathematicalPhysicist

    Comparing Soap and Shampoo: Understanding the Differences

    What's the difference between the two?
  31. C

    What Is the Longest Wavelength Enhanced in a Thin Soap Film?

    Homework Statement A soap film is 129 nm thick. The film is in air and illuminated by white light at normal incidence as shown in the figure below. (In the figure the rays have been drawn at an angle to show the multiple reflections and transmissions in the film.) Assume the index of...
  32. B

    Soap Bubble interference-verify answer

    Homework Statement A soap bubble is essentially a very thin film of water (n=1.33) surrounded by air. The colors thata you see in the soap bubbles are produced by interference. Derive an expression for the wavelengths for which constructive interference casues a strong reflection from a...
  33. N

    Physics & Math of Soap Films & Bubbles

    I'm looking for some stuff concerning the physics and mathematics of soap films and soap bubbles - I mean things like the surface tension mechanism, Young-Laplace equation etc. and the mathematical side of the subject, i.e. minimal surfaces, mean curvature etc. I know that there are two nice...
  34. Math Is Hard

    MIH goes to the hippy soap shop

    So I decided to spend a little of my stimulus check to help local merchants. I went down to our local soap vendor. They have beautiful handmade soaps that they create right there in the shop and they smell so nice. I'm browsing around, and this guy comes in the store looking and sounding like...
  35. F

    How Do Phase Shifts and Path Differences Affect Interference in Soap Films?

    [SOLVED] Interference in Soap films Homework Statement The sketch View Figure shows a thin film of soapy water of uniform thickness t and index of refraction n = 1.33 suspended in air. Consider rays 1 and 2 emerging from the film: Ray 1 represents the reflected wave at the air-film...
  36. S

    Discover the Vibrant Colors of Soap Bubbles: Red or Blue Near the Bottom?

    Which of the following colours would you expect to see near the bottom of a soap bubble, red or blue? this is my solution If the thickness of the soap bubble is much smaller than the wavelength of light, the result is destructive interference (dark color). The thickness required to produce...
  37. 4

    How Does Soap Film Thickness Affect Color Reflection in Optics?

    Soap Bubbles in terms of optics etc. Help needed :) Homework Statement The opening of a metal cylinder is dipped in soapy water so that a soap film forms. The cylinder is then turned so it is horizontal (and the soap film is vertical). What happens to the thickness of the soap film...
  38. L

    How can I find the minimum volume of two rings in soap water with given radii?

    Two rings with radius R and r are let down in the soap water. Between them pellicle appeared (like in image). Image: here all are symmetric ;) problem: need to find y=f(x) what i think:volume of figure is minim. maybe express volume via needed function, then get minimum of volume, and find...
  39. Ivan Seeking

    Antibacterial Soap No Better And May Be Worse Than Plain Soap

    http://www.medpagetoday.com/InfectiousDisease/GeneralInfectiousDisease/tb/6432 I have often wondered about this. AFAIK contact time is always important for antibacterial agents, but I checked some soap that we had which only says to wash hands, and rinse. .
  40. Loren Booda

    Soap bubble measures electric field

    Can one determine a local electric field by the change in interference spectrum of a soap bubble? If one notes the spectrum with E=0, then applies a nonzero E-field, would the effect of the induced repulsive charge on iridescence be relatively easy to calculate, given the additional variable of...
  41. Facial

    Coefficient of friction in soap?

    What are the static and dynamic friction values for dry and wet soap? I can't find these things anywhere on the net, except for an assumption of the kinetic value of 0.06. If someone has access to an extensive data sheet on frictional values, then that would help greatly. Thanx
  42. larkspur

    Best Tool to Cut a Large Bar of Soap in Half

    What would be the best way to cut a very large bar of soap in half? I have a bar of triple milled soap that is 11cm long, 7cm wide and 4cm thick. My hands too small to hold on to this bar in the shower. I have a miter box and the saw that came with it or a hack saw. Which one would be...
  43. C

    Antibacterial Soap: How Trichlorocarbanilide Kills Bacteria

    How exactly does trichlorocarbanilide kill bacteria?
  44. I

    Soap Making - Chemistry Project

    Greetings, We're doing a project in which we are investigating the effects of sodium laureth sulphate and ammonium lauryl sulphate on the human body (these are surfactants). NOW, we would like to know exactly how to make soap. we need direct procedures on the saponification process...
  45. S

    Help with Complex Chemical Reactions Needed

    i need help with some complex chemical reactions if anyone would like to take a shot at it... i would greatly appreciate any effort :uhh:
  46. P

    Why Does a Soap Film of Thickness Lambda/4 Maximize Brightness?

    There is a soap film of thickness t in air. I don't understand intuitively why a film thickness of of t = lambda/4 where lambda is the length of the light that is incident upon the film, results in maximum brightness of the light. I know that this is true from the equation for interference but...
  47. M

    Prevent Bathroom Mirror Fogging with Soap

    Whenever you take a shower the bathroom mirror fogs. I discovered if one rubs a thin layer of soap on the mirror, then gently rubs it in with a cloth, the mirror does not fog. I could not think of any other reason other than some chemical reason. Why does this happen?
  48. D

    Does dish soap emulsify lipids in the cell membrane?

    http://www.google.ca/search?q=cache:0j8NdYaQ3L4J:www.foodsafetynetwork.ca/biotechres/activityextraction.pdf+Kiwi+DNA+Extraction+Lab&hl=en The above url is a lab that states that to do a DNA extraction of kiwi the cell membrane is eliminated through liquid detergent and mechincal mashing -...
  49. T

    Why is my bum itching after washing my jeans with cheap soap and cold water?

    I think I've figured out why I've been so grumpy lately. My bum has been itching like crazy. I don't think all the soap rinsed out of that last batch of Levi's I washed. I couldn't figure out why I had a rash on my bum and inner thighs, I hadn't switched brands of adult diapers recently, but I...
  50. R

    Why do some soap bubbles stay intact for longer periods?

    Hi, Why do some soap bubbles stay intact for longer periods?And what is the reason for the changes in color of the bubbles? Thanks!
Back
Top