Questions tagged [bubble]

A coherent region of fluid embedded in a fluid with different properties (air in water) or a coherent region of fluid surrounded by a membrane embedded in a fluid which may or may not be different (such as air in a soap membrane).

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46 views

Movement of bubbles in a cup of tea

Why is it that when I try to scoop bubbles out from the surface of a cup of tea, they always slip off the spoon even if some of the tea does not?
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12 views

What kind of forces develop on a solid shape suspended in bubbly fluid? Is there a name for the study of this sort of interaction?

Let's say I have a solid shape - a sphere, a cylinder, I don't know if it matters - and I place that solid in a container of water. The forces on the shape consist of gravity and buoyancy (due to ...
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27 views

Does a thickness of a bubble become constant over time?

Assuming no gravity, imagine you have a bubble floating in the air, does its thickness have a tendency to become constant? State a bit differently, if we start with a bubble with variable thickness, ...
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1answer
45 views

Bubble optics, impact

My 8 years old daughter was blowing soap bubbles. Most of the bubbles had color. She randomly choses a bubble with colors and lands it on the wand. Instantly it's color is gone. If she blows this ...
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1answer
31 views

Bubbles in a Pipeline 2

This question has kind of been asked before here, but aren't the gas bubbles in the pipeline also a moving fluid and so as they get constricted shouldn't their pressure decrease too. If so how are ...
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15 views

Bubble flow in vertical pipe

I have an application where I would like to keep a bubble flowing freely within a pipe. Assume a single small, spherical, non-deforming gas bubble in a viscous, laminar fluid flowing in a vertical ...
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2answers
73 views

Optics of thick soap bubbles

There was some discussion in a previous thread ( Why are thin soap bubbles colorless? ) that talked about thin soap bubbles. My question is, what if we go the opposite way? Why are thick bubbles ...
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1answer
69 views

Why do soap bubbles seem to resist merging?

When playing with soap bubbles in a bathtub, it seems impossible to bring two bubbles together to form a single larger bubble. When two floating bubbles meet, a wall is formed between them. Even when ...
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1answer
46 views

Why are there less bubbles the second time I pour soda in the cup?

I poured some Pepsi into a mug, and it foamed, and I poured until the foam was at the top of the glass. I waited a few seconds for the bubbles to go, and the liquid level was revealed to be at around ...
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1answer
51 views

Why does soap solution forms bubble but tap water does not? [duplicate]

The surface tension of water reduces on addition of soap to it. Then why does normal water not form bubbles but soap does even with less surface tension?
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2answers
62 views

Why does air get trapped below water pouring into a glass?

The drinking-water-tap at my workplace has a low pressure continuous stream of water. When I pour water into a glass which has at least about (depth) 5cm of water in it, surprisingly large air bubbles ...
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What is the equation of state of foam, on a macroscopic scale?

Consider a large amount of soap foam (or any other substance producing foam), of mass density $\rho$ in a gravityless environment. What is the internal pressure $p$ of that foam, viewed as a fluid on ...
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31 views

Water vapor pressure in oxygen bubble

Suppose we have a source of O$_2$ bubble formation in water at specific nucleation sites, how can we estimate the water vapor pressure inside the O$_2$ bubbles? I know that: (1): $p_\mathrm{O_2}+p_\...
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1answer
93 views

Surface tension and entropy

I think of surface tension as work/area, just as pressure is work/volume. I understand it to measure energy rather than free energy. I should think that a molecule on the surface of a liquid would ...
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4answers
2k views

Why are we able to see air bubbles under water?

Title is self explanatory. I'm assuming both water and air are transparent. So, if they are true, how can I clearly distinguish an air bubble under water?
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2answers
865 views

Why do bubbles initially stick to the side or the bottom of a glass while boiling?

When boiling water, I've noticed that bubbles will appear to grow at the bottom of the glass for a period of time and then rise. I've read that bubbles form from nucleation centers but I don't know ...
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49 views

How long does it take for oil to coalesce in water?

I was studying the process of coalescence in emulsions. We considered $N$ bubbles of liquid 1 floating in liquid 2. The result we derived, is that if there are some dissipative forces (diffusion) the ...
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1answer
33 views

What keeps small mobile bubbles at the bottom of a kettle from rising

We have a glass jug water kettle with a flat heat plate as the bottom. It boils water quite vigorously in 2-6 minutes depending on how full with a 1000+W element. Just today I noticed that very ...
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1answer
236 views

Pressure inside a bubble

Consider a bubble with radius $r$, inner pressure $P_v$, and outer pressure $P_{\infty}$. When we choose our control volume (blue dotted line in figure) to encompass half the bubble, we have a surface ...
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2answers
282 views

Why are the “bubbles” at the edges of my soup so large?

At lunch today, I was eating chicken noodle soup. After finishing most of it, I turned my attention to a sandwich and let the soup sit for about five to ten minutes. When I looked back, I noticed that ...
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1answer
69 views

Champagne bubbles and gravity

One of the influences on bubble size is the speed with which a bubble rises in a glass - this, I believe, is due to the force of gravity which acts on the liquid around the CO2. The greater the ...
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0answers
35 views

Why do bubble rings stop rising near the surface, and then spontaneously dissipate?

When I've blown bubble rings in my pool I've noticed that every single time a ring rises to the surface it stops rising about 1-2 centimeters from the surface, stopping in place. Then, it ...
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1answer
51 views

Best way to pour a too-carbonated beer?

I hope people have fun with this. But, for those who aren't interested in fun, here's a Tl/Dr: What is the fastest way to disperse foam from an overcabonated drink being poured. For example, is it ...
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2answers
74 views

Bubble with varying pressure over surface

I was wondering if it's possible to have a soap bubble with a varying pressure over its surface? That is, such a bubble would not have constant internal pressure at all points. I am specifically ...
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1answer
217 views

Why does not a bubble in a thick hand sanitiser not rise?

Here is a picture of a bubble trapped inside a thick hand sanitiser. These bubbles never rise despite not sticking to the walls! They just remain stationary, in the middle of the liquid, despite the ...
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1answer
42 views

Is the trajectory of a bubble a good indicator of the direction and velocity of air flow?

I'm wondering if a soap bubble is a good "measurement device" for the flow field of air it is surrounded by. If I could somehow create many bubbles in an array, could I infer the flow field of the air ...
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1answer
195 views

Is it possible to create a soap bubble in space?

since space does not contain air, is it possible to create a soap bubble without air in space or in vacuum and can can you explain why so? OR will there be any possibilities for a bubble in such kind ...
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118 views

Will a soap bubble remain stable if its surface is uniformly charged?

Considering a uniformly charged spherical shell, it is easy to show with a virtual work argument that the pressure will be given by $$ p = \frac{Q^2}{32\pi^2 \epsilon_0 R^4} $$ On the other side, ...
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2answers
67 views

Can bubbles lower water pressure?

After watching a TV show I saw that bubbles originating from underwater can lower the impact damage when something hit it at velocity. I was wondering if another implementation of this would work. ...
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1answer
74 views

What is causing the repeated creation and destruction of bubbles in boiling starchy water?

A while ago I was cooking rice, and I noticed a recurring pattern of creation and destruction of bubbles. It seemed like the bubble-layer would increase in height, until it 'popped', and the layer ...
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2answers
186 views

What determines the lifetime of a soap bubble?

I'm wondering why soap bubbles only last some seconds in average. There is almost no wind in the closed environment I create the bubbles in. Regardless of whether they adhere to a surface (e.g. the ...
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2answers
44 views

In a real life system of waving a bubble wand or baton around how do you determine when chaos has occurred?

In a real life system of waving a bubble wand or baton around how do you determine when chaos has occurred?
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1answer
105 views

Is the energy of sonoluminescence derived solely from ultrasound?

Sonoluminescence occurs when a small gas bubble is oscillated in a liquid solution with ultrasonic frequencies. The bubble's collapse and cavitation results in light emission and thermal energies that ...
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2answers
441 views

What can be the simplest way to find the thickness of a soap bubble?

Is it possible to measure the thickness of a soap bubble without using any sophisticated instruments such that anyone can do it?
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2answers
48 views

To what depth can I lower this tube? [closed]

This is a problem I came across: Imagine there is a glass test-tube with a small hole of radius ‘r’ at the bottom of the tube. Now this tube is lowered into a water-filled beaker; upto what depth ‘d’ ...
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2answers
356 views

Bubble formation in long plastic tube with glass windows sealing the ends

Suppose you have a plastic tube that's length is much longer than its inner diameter sealed with glass on both ends. Inside the tube is high purity water with no bubbles i.e. all gases that remain in ...
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2answers
73 views

Hot air balloon tearing

What will happen if there is a tearing in hot air balloon? Is there a difference between pressure so the balloon will be pushed? I have tried ti read a lot of essays but there was no answer!
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1answer
63 views

Speed of Bubble in Coke

I was trying to solve the following problem, but my results seem illogical when I graph my solution. Assuming we have a bubble at the end of a coke glass, I want to solve for the speed of the bubble ...
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1answer
137 views

Could LIGO have detected R'lyeh if it existed?

In Possible Bubbles of Spacetime Curvature in the South Pacific, that R'lyeh might be exist within a bubble of spacetime. (It appears to be a joke paper since some of the references are fictional, but ...
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1answer
87 views

Do underwater acoustic waves create bubbles?

I am working on a science fair project, and I currently need to develop a hypothesis. I am having a little trouble, but I have some ideas. I just need one answer so that I can go on about this. I ...
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1answer
120 views

Bubble Formation in Froth Flotation process

I've recently attended a lecture on the metallurgical process of froth flotation. To make us understand froth, my teacher gave us the example of soap bubbles. But in actual practice, the flotation ...
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2answers
118 views

What is the physical process when you uncork a bottle in a shoe hitting a wall?

When you want to uncork for example a champagne bottle you can put it in shoe and hitting the bottom of the shoe against a wall. By this the liquid is pushing out the cork. But is this process just a ...
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1answer
453 views

Why is there bubble in the boiling water?

Whenever we boil water there, there comes bubble from the bottom surface of the kettle when the water reaches 100 degree Celsius. Why is that? We also see some bubble sticking to the surface even ...
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1answer
449 views

Why are thin soap bubbles colorless?

I read here that: The colors of a bubble are dependent on the thickness of the film. A bubble becomes thinner and thinner as it dries out (due to evaporation), before finally popping. As the ...
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3answers
298 views

Soap bubbles in laser light

I have experienced an interesting phenomenon this weekend. It involved : Soap bubbles which were ... ... flying around while laser light was drawing images around the walls All this accompanied by ...
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1answer
430 views

Why can one not blow a soap bubble with pure water even if its surface tension is higher?

So surface tension increases as the length increases. I know that. But what doesn't make sense is if I have a bucket of water, and then suspend a needle on the top. The surface tension of the water ...
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0answers
60 views

Is it true that the bubbles do not touch each other in the boiling water while going up?

I heard once that the bubbles do not touch when the water is boiling. I want to know if that is actually happening, and I would be interested to hear why it is true or not.
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1answer
1k views

Soap bubble question, surface tension and excess pressure [closed]

A soap bubble is blown slowly at the end of a tube by a pump supplying air at a constant rate. Draw a graph to represent the variation between the excess pressure inside the bubble with time.
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1answer
3k views

Which balloon has the higher pressure and why?

I know that when two soap bubbles of different radii are connected by a tube then air will flow from the smaller bubble to the bigger bubble. This happens because the pressure inside the smaller ...
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1answer
522 views

Why soap bubbles are made of soap?

Why are soap bubbles made of soap? What I know is to have stability in bubble, waterproofing agents should me mixed, but soaps are water wetting agents, and water wetting agents will decrease angle ...