Why reduce the surface tension of liquids, liquids are prone to foaming

Because water has surface tension, it tends to reduce its energy (i.e., reduce its surface area), but when surfactant is added, the surface tension of water decreases, and then the surface area of the water increases, and then it can foam.

This is the content of surface tension in Physical Chemistry.

Liquid surface tension refers to the liquid's own contraction, so if you reduce the surface tension of the liquid, it will of course be prone to bubbles!

Blowing bubbles into a basin of clear water, the bubbles burst when they rise to the liquid level, but add some laundry detergent to the water, and then blow the bubbles, and when the bubbles rise to the liquid level, the bubbles will not burst

1. Why can foam when the surface tension is reduced?

2. What is the substantial difference between bubbles with laundry detergent and bubbles without laundry detergent in the bubbles themselves?

3. Blowing bubbles in a basin without laundry detergent, and the bubbles burst when the bubbles rise to the liquid level, what is the force that causes the bubbles to burst?

1. The surface tension is reduced, the binding force between the molecules decreases, and the force of the bubble being "pulled" decreases, and at this time, the pressure difference between a certain point inside the liquid and the atmosphere remains unchanged, and the bubble is easy to come out.

2. The bubbles with laundry detergent are the same as the bubbles without adding laundry detergent, the difference is that the surface tension decreases after adding laundry detergent, and the force of "holding" the bubbles is smaller, and at the same time, due to the increase in viscosity, the bubbles can become larger and not broken.

3. Blowing bubbles in water without washing powder, in the process of bubbles rising to the surface of the liquid, the pressure = gh drops, the liquid is pulled downward by the earth's gravity, forming a tensile force on the upper surface of the bubbles, the higher the bubbles rise, the atmospheric pressure drops, the greater the pulling force, and at the same time, when the pressure in the bubble is greater than the atmospheric pressure at a certain point, the bubble bursts.

1.Surface tension, to put it bluntly, is similar to the "fixed" effect, remember when I was studying chemistry, I had to look at the concave liquid level when I looked at the readings of the test tube. The formation of this concave liquid surface is said to be capillary force, which is actually surface tension.

The periphery and the wall of the test tube will rise, but the middle part will not, and this is its function and significance.

In other words, this basin of water doesn't want to lose its water for no reason, so "grab it". By reducing the surface tension, the blisters can come out easily.

2 There is no difference in essence, just like mineral water and cola, they are both beverages, but the ingredients are different.

3 atmospheric pressure.

Causes of bubble formation: Bubbles are formed due to the surface tension of water. This tension is the mutual traction force that exists inside the object and is perpendicular to the contact surface of two adjacent parts when it is subjected to a tensile force.

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.

The method of slowing down the disappearance of bubbles: the evaporation of water is very fast, when the water evaporates, the surface of the bubbles is broken, and the bubbles disappear, therefore, some substances must be added to the bubble solution to prevent the evaporation of water, and this kind of substance with water-collecting properties is called hygroscopic. Glycerin is a hygroscopic liquid that forms a weak chemical bond with water, which slows down the evaporation of water.

The use of soapy water will affect the effect of blowing bubbles. Generally, soapy water made with 2 parts of dishwashing concentrate and 6 parts of water can be used. To make the bubbles last, change the recipe to 2 parts dishwashing detergent plus 6 parts water and 1 to 4 parts glycerin.

For ordinary bubbles, when you touch the bubbles with your hands, the water in your hands attracts the water molecules on the bubbles, destroying the surface tension of the bubbles, so they will burst.

Because the surface tension coefficient of the water is changed.