Bilingual edition: English is preserved and Chinese follows each unit. Terminology uses the confirmed v20260916 glossary; automated semantic review remains traceable.
中英双语版：英文原文完整保留，中文紧随对应单元；术语采用 v20260916 确认表，自动语义审校结果可追溯。

Surface Tension and Bubbles

表面张力与气泡

The surface tension of water provides the necessary wall tension for the formation of bubbles with water. The tendency to minimize that wall tension pulls the bubbles into spherical shapes (LaPlace's law).

水的表面张力提供了形成水泡所需的壁张力。为了最小化这种壁张力，气泡会趋向于形成球形（拉普拉斯定律）。

The interference colors indicate that the thickness of the soap film is on the order of a few wavelengths of visible light. Even though the soap film has less surface tension than pure water, which would pull itself into tiny droplets, it is nevertheless strong to be able to maintain the bubble with such a small thickness.

干涉色表明肥皂膜的厚度大约在可见光波长的几个数量级上。尽管肥皂膜的表面张力比纯水小，而纯水会自己聚成小液滴，但它仍然足够强，能够维持如此小的厚度的气泡。

The pressure difference between the inside and outside of a bubble depends upon the surface tension and the radius of the bubble. The relationship can be obtained by visualizing the bubble as two hemispheres and noting that the internal pressure which tends to push the hemispheres apart is counteracted by the surface tension acting around the cirumference of the circle.

气泡内外的压强差取决于表面张力和气泡的半径。这种关系可以通过将气泡视为两个半球体，并注意到试图将半球体推开的内部压强被表面张力在圆周周围抵消来获得。

For a bubble with two surfaces providing tension, the pressure relationship is:

对于有两个表面提供张力的气泡，压力关系为：
Derive the relationship
导出关系
Soap bubbles
肥皂泡
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Bubble Pressure

气泡压力

The net upward force on the top hemisphere of the bubble is just the pressure difference times the area of the equatorial circle:

作用在气泡上半球体上的净向上力就是压强差乘以赤道圆的面积：

The force of the surface tension downward on the entire circumference of the circle is twice the surface tension times the circumference, since two surfaces contribute to the force:

作用在圆周整个周长上的表面张力的力是表面张力乘以周长的两倍，因为有两个表面贡献于该力：

This gives

这给出了

This latter case also applies to the case of a bubble surrounded by a liquid, such as the case of the alveoli of the lungs.

这种情形也适用于气泡周围被液体包围的情况，例如肺部的肺泡情形。
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Surface Tension and Droplets

表面张力和液滴

Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. The spherical shape minimizes then necessary "wall tension" of the surface layer according to LaPlace's law. At left is a single early morning dewdrop in an emerging dogwood blossom.

表面张力决定了液滴的形状。尽管容易变形，水滴由于表面层的内聚力作用，倾向于呈现球形。根据拉普拉斯定律，球形能够最小化表面层所需的‘壁张力’。图中左侧是一颗清晨的露珠，位于初开的木槿花中。

Surface tension and adhesion determine the shape of this drop on a twig. It dropped a short time later, and took a more nearly spherical shape as it fell. Falling drops take a variety of shapes due to oscillation and the effects of air friction.

表面张力和附着力决定了这个水滴在树枝上的形状。它在一段时间后落下，并在下落过程中逐渐接近球形。下落的水滴由于振荡和空气摩擦的影响，呈现出多种形状。

A water droplet can act as lens and form an image as a simple magnifier.

水滴可以作为透镜，形成放大镜效果的像。

The relatively high surface tension of water accounts for the ease with which it can be nebulized, or placed into aerosol form. Low surface tension liquids tend to evaporate quickly and are difficult to keep in an aerosol form. All liquids display surface tension to some degree. The surface tension of liquid lead is utilized to advantage in the manufacture of various sizes of lead shot. Molten lead is poured through a screen of the desired mesh size at the top of a tower. The surface tension pulls the lead into spherical balls, and it solidifies in that form before it reaches the bottom of the tower.

水相对较高的表面张力使得它容易被雾化，或转化为气溶胶形式。表面张力较低的液体往往蒸发得较快，难以保持气溶胶形式。所有液体在一定程度上都表现出表面张力。液体铅的表面张力在制造各种大小的铅球时得到了充分利用。熔融的铅通过塔顶的筛网倒入，表面张力将铅拉成球形，它在到达塔底之前便凝固成这种形状。
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Capillary Action

毛细作用

Capillary action is the result of adhesion and surface tension. Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus which turns upward. The surface tension acts to hold the surface intact, so instead of just the edges moving upward, the whole liquid surface is dragged upward.

毛细作用是粘附力和表面张力的结果。水附着在容器壁上会使得液体边缘产生向上的力，从而形成一个向上的弯月面。表面张力会将液体表面保持完整，因此不只是边缘向上移动，整个液体表面都会被向上拖动。

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Capillary Action

毛细作用

Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules. The height to which capillary action will take water in a uniform circular tube is limited by surface tension. Acting around the circumference, the upward force is

毛细作用发生在液体分子之间的内聚力比液体对容器壁的附着力强时。毛细作用使水在均匀圆形管中上升的高度受表面张力限制。作用在周长上的向上的力是

The height h to which capillary action will lift water depends upon the weight of water which the surface tension will lift:

毛细作用将水提升的高度h取决于表面张力能提升的水的重量：

The height to which the liquid can be lifted is given by

液体可被提升的高度由以下公式给出
Show calculation
展示计算
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Capillary Action Calculation

毛细作用计算

The height h to which Capillary action will lift water depends upon the weight of water which the surface tension will lift:

毛细作用将水提升的高度h取决于表面张力能提升的水的重量：

The height to which the liquid can be lifted is given by

液体可被提升的高度由以下公式给出
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