布朗运动和扩散

我们环境中的一切都是由微小的碎片或粒子组成的。原子或分子是构成物质的粒子。粒子构成了我们的身体、椅子、桌子、书籍和其他物体。另一方面，万物中的粒子数量是巨大的。即使使用高倍显微镜，也无法看到构成物质的颗粒，因为它们太小了。我们有确凿的证据表明，所有的东西都是由小粒子组成的，即使它们是看不见的。让我们看一些证明一切都是由小粒子组成的证据。

物质中粒子的证据

扩散实验或不同物质自身的混合以及布朗运动为物质中存在粒子提供了证据。如果我们假设物质是由运动中的微观粒子组成的，那么很容易解释各种测试中发生的事情。然而，如果没有粒子的概念，事情就会变得非常难以描述。我们现在将进行一些实验，例如“固体溶解在液体中”、“两种气体的混合”和“花粉粒在水中的运动”，这些只能通过认为一切都是由微观粒子组成的实验来解释的。不断移动。这些将在下面进一步讨论。

• 将固体溶解在液体中

由于高锰酸钾是一种紫色固体，而水是一种无色液体，我们先来看看它是如何溶解在水中的。即使不搅拌，烧杯中的高锰酸钾晶体也会使水自行变成紫色。高锰酸钾的紫色在烧杯的水中蔓延，可以解释如下。

Small particles make up both potassium permanganate crystals and water. Potassium permanganate particles are purple in colour, whereas water particles are colourless. When a crystal of potassium permanganate is submerged in water, the particles separate from one another. These purple-coloured potassium permanganate particles dispersed throughout the water, turning it purple. Actually, as potassium permanganate dissolves, the particles of potassium permanganate go into the gaps between the water particles.

Without any external stirring, the particles of potassium permanganate and those of water combine on their own in this experiment. The particles of potassium permanganate and water spread into each other and mix up on their own, therefore they are moving or they are in motion is the conclusion. The colour could not spread across the beaker on its own if the particles were not moving. Diffusion is the movement of various particles among themselves on their own, resulting in uniform mixing.

• 两种气体的混合

空气是无色气体或气体混合物。气罐实际上是空的时充满了空气。这是因为我们看不到煤气罐里的空气，因为它是无色的。溴是一种呈红棕色的液体。它会产生大量蒸汽。溴蒸气，通常称为溴气，是一种比空气重的红棕色气体。现在让我们对实验进行测试。

一个充气的气罐倒置在一个充满溴蒸气的气罐上。来自下部气罐的红棕色溴蒸气将向上扩散到上部气罐中的空气中。装有空气的气罐在一段时间内完全变成红褐色。溴蒸气扩散到空气中可以描述如下。空气和蒸汽都是由四处移动的微小颗粒组成的。当溴蒸气和空气的运动颗粒在各个方向碰撞和弹跳时，它们被均匀混合。尽管溴蒸气比空气重，但它克服重力并与上部罐中的空气混合，因为它的颗粒以高速移动，为它们提供足够的动能来克服重力并进入装有空气的气罐。

Diffusion- Diffusion is the spreading out and mixing of a substance with another substance as a result of the movement of its particles. It is a crucial process that occurs in all living things. Diffusion is a process that aids in the movement of molecules into and out of cells. The molecules travel from a high-concentration region to a low-concentration region until the concentration is uniform throughout. Diffusion occurs in liquids and gases because molecules can flow at random.

Diffusion is a process in which matter moves from a location of high concentration to a region of low concentration due to the random mobility of molecules. We can draw two conclusions about the nature of matter from the diffusion process. The following are the conclusions:

• The substance is made up of thousands of tiny particles.
• Matter particles are in constant motion.

• 花粉粒在水中的运动

1827 年，罗伯特·布朗提出了支持液体中粒子存在和流动性的最佳证据。罗伯特·布朗用水来悬浮极小的花粉粒。正如在显微镜下观察到的，花粉粒以极其不规则或锯齿形的方式在水面上快速移动。人们还发现，花粉粒在水面上移动得越快，水就越暖和。

花粉粒在水面上的运动可以用以下方式解释。水由非常小的颗粒组成，它们移动得非常快。由于水颗粒或水分子是如此微小，它们在显微镜下是不可见的。由于花粉粒经常受到快速移动的水颗粒的影响，它们漂浮在水面上。因此，即使水颗粒或水分子太小而无法看到，它们对花粉粒的影响也是清晰可见的。布朗运动，以首先注意到这一现象的物理学家罗伯特布朗命名，是可见粒子或花粉粒由更小的看不见的水粒子产生的随机运动。

Brownian Movement- Brownian movement can be seen in gases as well. When a beam of sunlight enters a room, we may sometimes observe microscopic dust particles suspended in the air moving quickly and randomly. This is an example where Brownian motion in gases (as air is a gas) is demonstrated. Since they are constantly impacted by fast-moving air particles, the small dust particles move around. Though we cannot see the incredibly minute particles or molecules of air, we can witness the effect created by their continuous and quick motions. The quick and random movement of small dust particles hanging in the air demonstrates that air is made up of particles that are continuously moving. Brownian motion is the zig-zag movement of tiny particles floating in a liquid or gas. The temperature rises as a result of Brownian motion. Brownian motion’s existence leads to two conclusions regarding the nature of matter. The following are the conclusions:

• Small particles make up matter.
• Matter particles are in continuous motion.

Brownian motion is the uncontrolled or irregular movement of particles in a fluid caused by collisions with other fast-moving molecules. Random particle movement is usually reported to be stronger in smaller particles, less viscous liquids, and at higher temperatures. These are some of the elements that influence a particle’s motion in a fluid.

示例问题

问题 1：在一束阳光下，微小的尘埃粒子随机移动。为什么这些尘埃颗粒会四处移动？

回答：

Small dust particles hanging in the air move fast and randomly when a beam of sunlight enters a room due to Brownian movement, which is the zig-zag movement of tiny particles floating in a liquid or gas.

问题 2：说出导致墨滴在烧杯水中扩散的机制。

回答：

Diffusion is the process through which an ink drop spreads all over a beaker of water.

问题 3：当温度下降时，扩散速率如何变化？

回答：

Since particles move slower at lower temperatures, so diffusion decreases when the temperature drops.

问题 4：哪个关键词最能解释粒子从高浓度到低浓度的运动？

回答：

The movement of particles from a high concentration to a low concentration is termed as diffusion.

问题5：为什么气体扩散得这么快？

回答：

Since the particles have a larger intermolecular space and kinetic energy in the vapor state, the gas diffuses quickly. As a result, these particles readily combine with air particles and move quicker.