Why do you need to make bubbles when washing your hands with soap?

You are right, the formation of bubbles is related to surface tension.

Soap is a type of surfactant, which also includes meal detergents, soaps (similar to soaps), laundry detergents and other preparations. Their effect is to reduce the surface tension of the liquid (usually water), which is macroscopically represented by the appearance of bubbles.

Why is it easy to foam when soapy water is used? Because in the natural state, the surface tension of the water is larger, so that the water film can not form a spherical shape, and the surfactant reduces the surface tension of the liquid, so there is the possibility of forming a spherical water film, and the spherical water film will not be broken by such a small surface tension in a certain period of time, so the soap will produce a large number of bubbles that are not easy to form in the natural state.

Soap "breaks" the surface tension of water. The mutual attraction between water molecules on the surface of the water is stronger than the attraction between water molecules and air. These water molecules are like they're glued together.

However, if the water molecules are overly bonded together, bubbles will not form easily. The soap "breaks" the surface tension of the water, reducing it to only 1 3 under normal conditions, which is the optimal tension required to blow bubbles.

Color bubbles: The soap film itself is colorless, like a transparent cellophane, and sunlight reflects off both the front and back of the soap film. When sunlight passes through the front and meets the back, it is immediately reflected back; The reflected light returns to the front, which in turn causes a certain reflection.

Sunlight is made up of seven monochromatic lights, and if there is a place in the soap film that cancels out the two reflected red rays, what you see in this place is the sunlight that has lost its red light, and it looks blue-green.

Here's how to make soapy water:

1. Cut the soap into thin slices and put it in a container, rinse it with boiling water and stir, melt and cool it.

2. Add a small spoon of granulated sugar or a little tea leaves to the soapy water, and put it in a dark place overnight, you will find that the bubbles blown out by this soapy water are not only bright in color, but also less likely to break.

It's really easy to make soapy water to blow bubbles, just use some soap and water to get together, then shake it, blow it with a straw, and the soapy water will blow the bubbles.

You must have blown a soap bubble bar, dissolved the soap in water, and then dipped a straw in soapy water and gently blew it, and it will blow colorful soap bubbles, which is fun. Why do soap bubbles blow out with soapy water?

Why soapy water blows bubbles

The surface layer of the liquid is different from the inside, its molecular distribution is sparser than that of the inside of the liquid, and the interaction between molecules is mainly gravitational force, which we call "surface tension", which causes the surface layer of the liquid to shrink, like an elastic film.

In summer, some insects crawl freely on the surface of the water, as if walking on the ground, and the surface tension of the water is one of the reasons. In addition, the shrinkage tendency of this "elastic film" minimizes the surface area of the liquid, so the dew droplets are "pulled" into a spherical shape. Of course, this is also the reason why soap bubbles take on a spherical shape.

So, soapy water can blow bubbles, is the surface tension of soapy water greater or smaller than ordinary water?

Wash two identical cups, pour in soapy water and pure water respectively, and add drop by drop when they are almost full, so that the liquid level is higher than the rim of the cup. At this time, you will notice that the bump formed by pure water at the mouth of the cup is higher than that formed by soapy water. That is, the surface tension of soapy water is less than that of pure water.

Because the surface tension of the water is too great, the water condenses tightly together, so it is difficult to blow open and bubbles are formed. When soap is dissolved in water, the surface tension of the water is reduced, and bubbles are easily blown out. Like a balloon, if the elasticity of the material is too strong, it will be difficult to blow up, and if the tightness is right, it will be easy to blow into a big bubble.

The soap dissolves in the water, and its molecules are still tightly pulled. When the air is blown in, the soapy water forms a stronger film. Depending on the amount of air blown in, it can be transformed into bubbles of different sizes.

Because soapy water can form a soap film, the soap film is not easy to break. When you blow, the soap film will inflate little by little and turn into a soap bubble, like blowing up a balloon. First of all, we have to figure out that liquids are mainly made up of many liquid molecules.

There is a tension on the surface of the liquid, and although it is called tension, it causes the molecules of the liquid to blow the bubbles tighter.

When we blow bubbles, the tension of the soapy water prevents the thin liquid film of the bubbles from bursting and wraps the air tightly inside. Due to the surface tension, the air inside the bubble is more pressurized than the atmosphere outside. Therefore, after the soap bubble is blown, it will automatically and slowly expand outward until it bursts and disappears.

The greater the surface tension of the solution, the more air is blown in, and the larger the bubble volume.

Soap is mainly composed of stearic (ZH) salt. The stearic acid molecule is an organic molecule and is much larger than the water molecule. With the composition of the soap, the attraction between the liquid molecules will be great.

The surface tension of soapy water is usually much higher than that of water molecules because the stearate molecule does not lack strength. As long as the tension resists the internal air pressure, the soap bubble will not burst. On the other hand, water molecules, which have a relatively low surface tension, are simply unable to resist atmospheric pressure and hence are unable to form bubbles.

If we add some sugar to the soapy water, because the sugar molecule is also an organic molecule and has a greater binding force than the stearic acid molecule. As a result, sweetened soapy water has greater surface tension and can blow out larger bubbles. If we add some vinegar to the soapy water, the acetic acid contained in the vinegar reacts with the stearic acid molecules, which reduces the surface tension of the soapy water and blows bubbles.

Soap is a mixture of grease and plant ash. There are many types of soaps with many different effects. Some sterilize well, some have a good fragrance, why does soap foam?

Do you know why? This is because soap will have a lot of surfactants in it. This surfactant, which has hydrophilic properties at one end (hydrophilic group) and water rejection at the other end, has water-repellent properties (hydrophobic group).

A surfactant is a chemical property that has two contradictory substances united together. When the surfactant is mixed with water, the hydrophilic end dissolves in the water, while the hydrophobic end breaks away from the water and collects on the surface. In the surfactant on the surface of the water, the hydrophobic group will leave the water surface and enter the air, and the hydrophilic group will dissolve in the water and be discharged on the water surface.

When you stir the water, you get air into the water, and the hydrophobic base envelops the air and becomes a bubble. That's why soap foams. The hydrophobic group of this surfactant is not water, it will accumulate on many substances, and if there is dirt appearing, it will adhere to its surroundings, and after the dirt is adsorbed by the hydrophobic group, the hydrophilic group will accumulate on the periphery, so some simple and easy-to-wash dirt will be washed away.

There is a certain tension on the surface of the liquid, and under the action of tension, a capillary phenomenon will be formed. This is due to the intermolecular force of attraction. And soap can break this tension, which forms a thin layer of liquid surrounding some gases, which is the phenomenon of soap bubbles.

Bubbles are formed due to the surface tension of water. Partial containment.

The mutual attraction between the molecules of water biratan on the surface of the water is stronger than that between the molecules of water and the air. These water molecules are like they're glued together. However, if the water molecules are overly bonded together, bubbles will not form easily.

Soap "breaks" the surface tension of the water, which is exactly the optimal tension needed to blow bubbles.

The disappearance of the bubble:

When the water evaporates, the bubbles disappear, therefore, glycerin can be added to the bubbles, which forms a weaker chemical bond with the water, which slows down the evaporation of the water.

Soapy water can't blow bubbles, soapy water can't be used to make bubble liquid, I'm really looking forward to it.