Soap Definition and 103 Threads

1.If the thickness of soap water surface decrease, whereas the concentration remain the same, how will the surface tension change? 2. If the membrane of soap water start to evaporate, its thickness become thinner and it’s concentration increase, How will the surface tension change? Thank you!

Is anyone very knowledgeable in making body or hand soap so can easily classify the main compounds' function and proportion Found on a body soap wrap written ingredient: Sodium Laureth Sulfate Laureth-4 Lauryl Alcohol Sodium Palmateiiii Sodium Palm Kernelate Palm Kernel Acid Paraffinum...

What actually typically is the emulsifier inside common dish soaps? Isn't another kind of soap, clothes or hand/body soap, also has such emulsifier in its ingredient ? But as what it seems and is found on internet, why commonly people make use of emulsifier only in the dish soap?

So here it is. I took a guess but I couldn't really answer, hopefully you can. Slow motion video of pulsations occurring while sucking liquid soap into a syringe.

I mention the details in the book (verbatim) in the form of a paragraph in green below. Later I ask my questions in blue font for better reading. "Surface tension also explains why hot, soapy water is used for washing. To wash clothing thoroughly, water must be forced through the tiny spaces...

I have solved it with a force approach, but would like to know how to do it via an energy approach. For starters, here is the force approach. Consider a small, approximately circular, surface element of mass ##m## such that the angle from the centre to the edge of this element is ##\alpha##...

This is an experiment I would have liked to do from the ISS, but an approximation could be done in a vacuum chamber on Earth. How big a soap bubble, polymer bubble, or glass bubble could you blow in the vacuum of space? How to calculate the evaporation rate in vacuum? A liquid exposed to vacuum...

Cell membranes are made of a bilayer of amphiphilic phospholipids, where the lipophilic portions of the molecules face toward each other, and the hydrophilic portions face outwards towards the cytoplasm or the external cellular environment which is aqueous and therefore orients those...

1. Two coaxial rings of radius R=10 cm are placed to a distance L from each other.There is a soap film connecting the two rings(that looks like a cylinder which have different radii with z coordinate. (The rings lie in xy plane)).Derive a differential equation describing the shape r(z) of the...

I have a Dettol automatic soap dispenser (see fig. 1) which uses a little propellor-type pump to let out a small amount of soap when you put your hand in front of the passive IR sensor. It's been working fine until just before, when I turned the lights off in the kitchen (night time, so...

Homework Statement Homework EquationsThe Attempt at a Solution Excess pressure inside a spherical soap bubble is 4S/R . How to deal with the cylindrical shape ? Why does the question specify it to be "long" ?

I don't understand, when calculating the force to change the surface area of the film, how the length obtained in the diagram below is "l" (lowercase L). I understand that there are two surfaces to overcome, hence the factor of 2, but why is the length perpedicular to the force used and not...

Homework Statement There is a total of ##Q## charge on soap bubble of radius ##R##. What force is acting on one hemisphere by the other ? Homework Equations Electrostatic pressure is ##P_e = 2\pi \sigma^2## for a spherical shell. The Attempt at a Solution ##P_e = F/A## therefore ##F =...

I want to keep a small space (oh, say, about the size of a chest humidor - call it 2 cubic feet) humid to a level of about 70% to 80%. I don't feel like using the whole humidity technology that you have to fill all the time, so I've just stuck a gallon bucket of water in there. I was wondering...

Homework Statement Would you see the same thin film interference pattern in a film of soap surrounded by air and a film of soap on glass? Why or why not? Homework Equations None The Attempt at a Solution Yes, you would see the same thin film interference pattern in a film of soap surrounded...

Bats in my garden do not seem to notice soap bubbles. Do soap bubbles reflect sound?

1. The problem statement, all variables and given/known da A soap bubble 500 nm thick is illuminated with white light. The index of refraction of this unique soap film is 1.35 for all colors (no dispersion). a) What wavelengths are not reflected? Homework Equations 2nt=mL 2nt=m(L/2) The...

For a system modelling a soap bubble, the differential work done is now given by: dW = −pdV + γdA, where γ is the surface tension and A the area. Compute new differential expressions for the potentials U, H, F, G. What are the new natural variables in each case? Are there any new Maxwell...

here is the problem. i got 0.5 from the fact that thickness = (m)(lambda)/(2nf) other equation for thickness is thickness = (m+1/2)(lambda)/(2nf)

A current hobby of mine. Long term savings in that a DE blade costs 10-30 cents compared to $1-4 disposable razors/cartridges. An initial purchase of a razor and brush together would cost no more than $40 on Amazon and they last a lifetime. I've tried electric razors ; anything under $150...

Homework Statement What should be the pressure inside a small air bubble of 0.1,, radius,situated just below the surface? st of water=7.2 *10-2 and atmospheric pressure=1.013*105. Homework EquationsThe Attempt at a Solution I am of the understanding that the pressure inside the...

Hi everybody, I now encounter some problems when try to solve this: Problem statement: Calculate the work done to blow a soap bubble to radius R. Knowing that the process is isotherm, the atmospheric pressure is H, the surface tension is γ. Solution: $$A = A_{1}+A_{2}$$ In which A1 is the work...

Hi guys, I'm doing a project at the moment revolving around capillary action and surface tension. Today I conducted an experiment to observe capillary action in a capillary tube and paper towel at different temperatures of water. I don't understand why I've got the following results: As you...

I found paint thinner (aka. mineral spirits in US, white spirit in UK) very useful in cleaning tough stains on tiles, etc. However I notice that even after washing my hand several times and rubbing for a long time with soap the smell of the paint thinner does not go away from my hands. I'm a...

Homework Statement I was wondering about how the placement of weight affects Soap Box Cars. I have been racing them for 5 years now, and I cannot find any information. I was wondering if there was a formula to find the relationship between speed and weight, and how to solve it. For instance, if...

A soap bubble or a nuclear detonation emit a sound created by the sudden release of pressured air? Am I correct? How is the sound of a knock on the door, two billiard balls hitting each other, etc. How is the sound generated in their cases? Thank you.

This is a fun, easy and super kid friendly experiment. Now, what exactly is happening here? :) https://www.youtube.com/watch?v=rqQSlEViNpk

Hi everyone, Just new to the forum and a novice electronic geek. I am trying to build a small cream dispenser with my daughter. Basically a hand held device that when you press a button automatically squeezes the bottle and dispenses a preset amount of cream. I know there are probably...

Hello. I have a question... I think that you know the experiment with pepper and soap. (you put water on plate, than you put a lot of pepper on in, than you put on your finger some soap and than you touch the plate). The pepper goes to edge of the plate. Only some of them fall in the water. It...

I bought a Stainless Steel soap bar and it works, it just does. It was from China and hollow inside and I would like to know if that's either a cost cutting measure or how the bar works? What would happen if it were solid? Another thing would be if it had a magnetic core, or made from a metal...

Homework Statement Two soap bubbles of radii 3cm and 2cm come in contact and sticks to each other. Calculate the radius of curvature of common surface. The Attempt at a Solution Excess pressure inside soap bubble = 4T/R Let the radius of common surface be R' \dfrac{4T}{R'} = \dfrac{4T}{r_1}...

Guys, do you know any comprehensive website or reference that explains everything about soap film analogy and sand heap analogy? Including their concepts, procedure on how to perform them and some animations. It will be more useful if the discussion also deals with the reinforced concrete...

on a soap bubble colours can be seen.my textbook says its due to the interference betwewn light waves from the top and the bottom surfaces of thin films.but how?so confused:confused: i tried googling for answer but still i can't find it

FDA examining antibacterial soaps, body washes http://www.cnn.com/2013/12/16/health/fda-antibacterial/

After reading throught the original thread about soapbox cars, I have a better understanding of what is happening. The soapbox derby that I'm in has few rules. You must have a 6" or less wheel, steering and some sort of brake. The hill is a constant slope and there is a 10' push zone. From...

When we dip a wire ring in a soap solution and then take it out, why does it form a soap film inside? Is there any explanation behind it?

Homework Statement (Ans: ##\pi F/(2L)##) Homework Equations The Attempt at a Solution I am not too much familiar with these type of questions so I don't really how to begin with this. Also, I don't understand the question here. Do we have to consider it in the vertical or...

I want to start a home project to creating different soap solutions. Dish washing detergent, carpet cleaning solution, and car cleaning soap are my main focuses. I have no idea where to start as my internet research is getting no where. What is soap made of and how can I experiment with...

I've heard that, when a soap bubble is given a charge, it expands. I was just wandering whether, when you wet a ring made of metal with a soap solution and blow to it slowly, the bubble created expands because of theat above principle. Does The friction between the metal ring and the bubble...

Homework Statement My soap dispenser does not work, but when i block the pump end the soap comes out, can someone explain to me why? Homework Equations I am looking for a relevant equation to prove why it doesn't work The Attempt at a Solution

Evening all, I've been curious about these caffeine soaps lately and thought that this would be the place to discuss about it. My almost-favorite website United Nuclear claims: "As it turns out, our good old friend Caffeine reaches the bloodstream faster through skin absorption...

It is said that a soap film will find the surface with the minimum area. If the two interfaces between the soap and the air meet, the soap film can effectively reduce its area by bursting. You would think that if you simply hold a soap film up vertically, all the liquid would want to go to the...

Homework Statement A soap bubble of radius 0.1mm has a wall thickness of 3.3x10^-8m, and is charged to a potential of 100V. Give a formula for the charge of the bubble. I know this is probably a really easy question, but I've only ever done problems with spheres of negligible wall...

I am doing an acid-base titration on liquid soap. I understand that buffers are used in soap. Would that affect the results of my titration? If so, how would I overcome this? Arthur.

is it possible to extract sodium hydroxide from liquid soap? i need to test the sodium hydroxide. if it is possible, how would i do it?

i'm doing a task to find the amount of sodium hydroxide (NaOH) in a liquid soap. i have to use titration in it. how exactly would I do this? thanks

Hello I am trying to start a small home business making soap. I am on a really tight budget and also very new to the extrusion process. While I may be extruding soap, I understand that the process is very similar to plastic extrusion. I want to extrude soap bars using a machine...

Homework Statement Two soap bubbles of equal radius 'r' coalesce isothermally to form a bigger bubble of radius 'R'. If the atmospheric pressure is P0, find the surface tension of the soap solution. Homework Equations Surface energy = surface tension x increase in area (W = T.ΔA)...

Two soap bubbles of radius r and R are in touch find the radius of curvature of their point of contact? (Both bubbles are touching each other with their external surfaces) I have no idea about this question. can you please try to help>