105 Changing States-Mid

Changing States FOCUS Question How does matter change from one state to another?

改变状态焦点问题物质如何从一种状态改变到另一种状态?

Everything Changes When ice melts in a glass of lemonade, it changes from solid to liquid Ice is a kind of matter. All matter takes up space and has weight. When matter changes state, it changes from one form to another. It might look different. But the tiny molecules that make it up remain the same. Water is still water, even when it is solid ice. The way molecules are organized and how they move changes in each state of matter. In solids, molecules are tightly packed. They move very slowly, In liquids, molecules are farther apart and bump into each other. Molecules in gases are spread even farther. They can crash into one another at high speeds.

当冰在一杯柠檬水里融化时，它就由固态变成液态。冰是一种物质。 一切物质都占有空间，都有重量。 当物质改变状态时，它从一种形式变成另一种形式。 它可能看起来不一样。但是组成它的微小分子保持不变。 水始终是水，即使它是固态的冰。 在物质的每一种状态下，分子的组织方式和运动方式都会发生变化。 在固体中，分子紧密排列。 它们移动得很慢。在液体中，分子之间的距离较远，会相互碰撞。 气体中的分子传播得更远。 它们可以高速相撞。

Critical Moments Substances can change state, which is also called a phase change. This happens when heat is added or removed. The melting point is the temperature at which a solid changes to a liquid. At the boiling point, a liquid changes to a gas. At the freezing point, a liquid changes to a solid Pressure can also affect phase changes. Air pressure is lower at higher elevations, where the air is thinner. Thinner air makes it easier for water molecules to escape the liquid and turn to water vapor. So in the mountains, water boils at a lower temperature. At sea level, the air pressure is higher. The water molecules must work harder to spread out. So it takes a higher temperature to change from liquid water to water vapor.

临界时刻物质可以改变状态，也称为相变。 这发生在热量增加或减少的时候。 熔点是固体变成液体的温度。 在沸点时，液体变成气体。 在冰点，液体变成固体的压力也会影响相变。 海拔越高，空气越稀薄，气压越低。 更稀薄的空气使水分子更容易逃离液体，变成水蒸气。 所以在山里，水的沸腾温度较低。 在海平面，气压更高。 水分子必须更加努力才能散开。 所以液态水变成水蒸气需要更高的温度。

Solid and Liquid Think of ice cream on a hot summer day. Solids turn to liquids when enough heat is added to reach the melting point. Heat energy makes the molecules move faster. Eventually, the molecules break away from one another. They spread out. The solid melts and becomes a liquid Generally, ice turns to water when it warms up to 0 degrees Celsius (32°F). The reverse happens when liquid water turns to ice. At the freezing point, molecules lose heat. They slow down and join together.

固体和液体想象一下炎炎夏日里的冰淇淋。 当增加足够的热量达到熔点时，固体就会变成液体。 热能使分子运动得更快。 最终，分子会彼此分离。 他们散开了。固体融化成为液体。一般来说，冰在温度上升到0摄氏度(32华氏度)时就会变成水。 当液态水变成冰时，情况正好相反。 在冰点，分子失去热量。 它们减速并结合在一起。

Liquid and Gas At high temperatures, liquids can turn into gases. This process is called vaporization When a liquid heats up slowly, it evaporates. Sunlight can warm the water in a puddle. The water evaporates as it warms. During boiling a liquid heats up and changes to a gas quickly. When a gas loses heat, it becomes liquid again. This state change is called condensation. Tiny drops of water fog up your bathroom. This is an example of condensation. The vapor from the hot shower cools and becomes liquid again. Science in Your World Liquid mixtures reach their boiling point at different temperatures. Water boils at 100°C (212°F), apple juice boils at 160°C (320°F), and olive oil boils at 572°C (1,062°F).

液体和气体在高温下，液体可以变成气体。 这个过程叫做汽化当液体慢慢加热时，它就会蒸发。 阳光可以使水坑里的水变暖。 水变暖时会蒸发。 在沸腾过程中，液体加热并迅速变成气体。 当气体失去热量时，它又变成液体。 这种状态变化称为凝结。 小水珠使你的浴室变得雾蒙蒙的。 这是缩合的一个例子。 热水澡中的蒸汽冷却后又变成液体。 液体混合物在不同的温度下达到沸点。 水在100°C(212°F)沸腾，苹果汁在160°C(320°F)沸腾，橄榄油在572°C(1062°F)沸腾。

Solid and Gas Usually, a solid goes through the liquid state before becoming a gas. But a solid can change directly into a gas. This process is called sublimation. Dry ice is a kind of ice made of carbon dioxide, not water. At room temperature, dry ice changes directly into a gas. If heat leaves a gas quickly, the gas can become a solid right away. This process is called deposition On cold nights, water vapor becomes solid ice, or frost. You can see frost on plants and other surfaces. Frost forms without becoming liquid water first. Wowser At- 218.8°C (361.8°F), it is possible to produce solid oxygen from its gaseous state.

固体和气体通常，固体在变成气体之前会经历液体状态。 但是固体可以直接变成气体。 这个过程叫做升华。 干冰是一种由二氧化碳而不是水构成的冰。 在室温下，干冰直接变成气体。 如果热量迅速离开气体，气体就会立即变成固体。 在寒冷的夜晚，水蒸气会变成固态冰或霜。 你可以在植物和其他表面上看到霜。 霜形成之前并没有变成液态水。 Wowser在- 218.8°C(361.8°F)时，可以从气态产生固体氧。