📚 The States of Matter Revisited | 物质的状态再探
In KS3 science, you met solids, liquids and gases. This article revisits the states of matter at a deeper level, linking observations to the particle model, energy changes and unusual behaviour such as floating ice.
在 KS3 科学中，你已经接触过固体、液体和气体。本文在更深的层次上重新探讨物质的状态，将观察到的现象与粒子模型、能量变化以及冰浮于水面等特殊行为联系起来。
1. The particle model revisited | 粒子模型再探
All matter is made of tiny particles. In the particle model, particles are always moving, have spaces between them, and attract one another. The amount of movement depends on temperature.
所有物质都由微小的粒子组成。在粒子模型中，粒子始终在运动，粒子之间存在空隙，并且相互吸引。运动程度取决于温度。
When a substance is heated, its particles gain kinetic energy and move faster. When it is cooled, the particles lose kinetic energy and move more slowly. This idea explains most physical changes.
当物质受热时，其粒子获得动能，运动加快。当物质冷却时，粒子失去动能，运动变慢。这一观点可以解释大多数物理变化。
2. Solids: fixed shape and volume | 固体：形状与体积固定
In a solid, particles are packed closely together in a regular pattern. They vibrate around fixed positions but do not move from place to place. This gives a solid a fixed shape and a fixed volume.
在固体中，粒子紧密堆积并呈规则排列。它们在固定的位置振动，但不会从一个位置移动到另一个位置。这使固体具有固定的形状和固定的体积。
Because the particles are already very close together, solids cannot be compressed easily. The strong attractive forces between particles also make many solids hard and difficult to break.
由于粒子已经非常紧密，固体不容易被压缩。粒子之间强大的吸引力也使许多固体坚硬且难以破坏。
3. Liquids: fixed volume, changing shape | 液体：体积固定，形状可变
In a liquid, particles are still close together but are arranged randomly. They can slide past one another, which allows a liquid to flow and take the shape of the bottom of its container.
在液体中，粒子仍然紧密但排列不规则。它们可以相互滑动，因此液体可以流动并呈现容器底部的形状。
A liquid has a fixed volume because the particles remain close together. However, it has no fixed shape. Like solids, liquids are difficult to compress because the particles have little free space between them.
液体具有固定的体积，因为粒子依然紧密。但液体没有固定的形状。与固体一样，液体难以压缩，因为粒子之间的自由空间很小。
4. Gases: no fixed shape or volume | 气体：形状与体积均不固定
In a gas, particles are far apart and move rapidly in all directions. They collide with each other and with the walls of their container. A gas has no fixed shape and no fixed volume.
在气体中，粒子相距很远，并朝各个方向快速运动。它们相互碰撞并与容器壁碰撞。气体没有固定的形状，也没有固定的体积。
A gas spreads out to fill its whole container. Because there is a lot of space between particles, gases are easy to compress. Their volume can be reduced by applying pressure.
气体会扩散并充满整个容器。由于粒子之间存在大量空间，气体容易被压缩。施加压力可以减小其体积。
5. Changes of state: melting and boiling | 状态变化：熔化与沸腾
Melting is the change from solid to liquid. Boiling is the change from liquid to gas. Both require heating because particles must gain enough energy to overcome attractive forces holding them together.
熔化是固体变为液体的过程。沸腾是液体变为气体的过程。两者都需要加热，因为粒子必须获得足够的能量来克服使它们聚集在一起的吸引力。
Pure substances have sharp melting points and boiling points. Impure substances often melt or boil over a range of temperatures, which is why purity can be tested by measuring these points.
纯物质具有明确的熔点和沸点。不纯物质通常在一个温度范围内熔化或沸腾，因此可通过测量熔点或沸点来检验物质的纯度。
solid → liquid → gas
加热时状态变化方向：固体 → 液体 → 气体
6. Freezing and condensing | 凝固与液化
Freezing is the change from liquid to solid. Condensing is the change from gas to liquid. During these reverse changes, particles lose energy, move more slowly, and become arranged more closely or more regularly.
凝固是液体变为固体的过程。液化是气体变为液体的过程。在这些逆过程中，粒子失去能量，运动变慢，排列变得更紧密或更规则。
Freezing and condensing release energy to the surroundings. For example, steam condensing on a cold window warms the glass slightly and releases latent heat, which is another name for hidden energy transferred during a state change.
凝固和液化会向周围环境释放能量。例如，水蒸气在冷窗户上凝结会使玻璃略微变暖，并释放潜热；潜热是状态变化过程中传递的隐藏能量的另一名称。
7. Sublimation and deposition | 升华与凝华
A few substances can change directly from solid to gas without becoming liquid. This is called sublimation. Solid carbon dioxide, known as dry ice, sublimes at room temperature and is used for fog effects.
少数物质可以不经过液态而直接由固体变为气体。这称为升华。固体二氧化碳，即干冰，在室温下升华，用于制造烟雾效果。
The reverse process, when a gas changes directly into a solid, is called deposition
Published by TutorHao | KS3 Chemistry Revision Series | aleveler.com
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