The kinetic particle model · 动理论粒子模型
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| particles/ˈpɑːtɪklz/ | 粒子 | lì zi |
| kinetic particle model/kɪˈnetɪk ˈpɑːtɪkl ˈmɒdl/ | 分子动理论 | fèn zǐ dòng lǐ lùn |
| solid/ˈsɒlɪd/ | 固体 | gù tǐ |
| liquid/ˈlɪkwɪd/ | 液体 | yè tǐ |
| gas/ɡæs/ | 气体 | qì tǐ |
| temperature/ˈtemprɪtʃə/ | 温度 | wēn dù |
| absolute zero/ˈæbsəluːt ˈzɪərəʊ/ | 绝对零度 | jué duì líng dù |
| kelvin/ˈkelvɪn/ | 开尔文 | kāi ěr wén |
| Brownian motion/ˈbraʊnɪən ˈməʊʃn/ | 布朗运动 | bù lǎng yùn dòng |
Everything is made of particles 粒子
- Look closely enough and all matter is tiny particles that never stop moving.
- This one idea — the kinetic particle model 分子动理论 — explains solids 固体, liquids 液体, gases 气体, heat and pressure.
- Let's see what the particles are doing.
一切都由粒子构成
- 看得足够仔细,所有物质都是从不停止运动的微小粒子。
- 这一个想法——动理论粒子模型(kinetic particle model)——解释固体、液体、气体、热和压强。
- 让我们看看粒子在做什么。
The three states of matter
- Solid — particles packed in a regular pattern, only vibrating. Fixed shape and volume.
- Liquid — particles still close but jumbled; they slide past each other. Fixed volume, takes the container's shape.
- Gas — particles far apart, fast and random. Fills the whole container.
物质的三种状态
- 固体——粒子以一个规则的图案紧密排列,只振动。固定的形状和体积。
- 液体——粒子仍然接近但杂乱;它们互相滑过。固定的体积,采取容器的形状。
- 气体——粒子相距很远、快速且随机。填满整个容器。
Squeeze a gas (Boyle's law) · 挤压一种气体(玻意耳定律)
Slide the piston in to shrink the volume. The same particles get crammed into less space, so they hit the walls more often and the pressure climbs — while pressure × volume stays constant. · 把活塞滑进去以缩小体积。同样的粒子被塞进更少的空间,所以它们更频繁地撞击壁而压强攀升——而压强 × 体积保持恒定。
In which state are the particles far apart, fast, and moving in random directions? · 在哪种状态中粒子相距很远、快速,并向随机方向运动?
Gas particles are far apart and move quickly in random directions, filling the container. Solids only vibrate; liquids slide past each other. · 气体粒子相距很远并向随机方向快速运动,填满容器。固体只振动;液体互相滑过。
Temperature 温度 and particle energy
- Heat a substance and its particles move faster — they gain kinetic energy.
- Temperature is a measure of the average kinetic energy of the particles.
- The lowest possible temperature is absolute zero 绝对零度, $-273\ {}^{\circ}\text{C}$ — particles have the least energy.
The particle model of solids, liquids and gases
温度与粒子能量
- 加热一种物质,它的粒子运动得更快——它们获得动能。
- 温度是粒子的平均动能的一个量度。
- 最低可能的温度是绝对零度(absolute zero),$-273\ {}^{\circ}\text{C}$——粒子有最少的能量。
固体、液体和气体的粒子模型
Temperature is a measure of: · 温度是以下的一个量度:
Hotter means the particles move faster, so temperature measures their average kinetic energy. · 更热意味着粒子运动更快,所以温度测量它们的平均动能。
The kelvin 开尔文 scale
- Scientists often measure temperature in kelvin (K), starting from absolute zero.
- To convert:
- So $0\ {}^{\circ}\text{C} = 273\ \text{K}$ and $27\ {}^{\circ}\text{C} = 300\ \text{K}$.
开尔文标度
- 科学家常常以开尔文(kelvin,K)测量温度,从绝对零度开始。
- 要转换:
- 所以 $0\ {}^{\circ}\text{C} = 273\ \text{K}$ 且 $27\ {}^{\circ}\text{C} = 300\ \text{K}$。
Convert $27\ {}^{\circ}\text{C}$ to kelvin. · 把 $27\ {}^{\circ}\text{C}$ 转换为开尔文。
$T = \theta + 273 = 27 + 273 = 300\ \text{K}$. · $T = \theta + 273 = 27 + 273 = 300\ \text{K}$。
Gas pressure
- Gas particles constantly hit the walls of their container. Each hit is a tiny push.
- The pressure is the total force of these hits on each unit of area.
- Heat the gas (fixed volume) → faster, harder, more frequent hits → higher pressure.
- Squeeze it smaller (fixed temperature) → more hits per second on each area → higher pressure.
- For a fixed mass of gas at constant temperature, $pV = \text{constant}$ (halve the volume → double the pressure).
气体压强
- 气体粒子不断撞击它们容器的壁。每次撞击是一个微小的推。
- 压强是这些撞击在每单位面积上的总力。
- 加热气体(固定体积)→ 更快、更猛、更频繁的撞击 → 更高的压强。
- 挤压它更小(固定温度)→ 每秒每面积更多撞击 → 更高的压强。
- 对一个固定质量的气体在恒定温度下,$pV = \text{constant}$(体积减半 → 压强加倍)。
A gas has a volume of $200\ \text{cm}^3$ at $100\ \text{kPa}$. It is squeezed to $100\ \text{cm}^3$ at constant temperature. What is the new pressure, in kPa? · 一种气体在 $100\ \text{kPa}$ 下有 $200\ \text{cm}^3$ 的体积。它在恒定温度下被挤压到 $100\ \text{cm}^3$。新的压强是多少,以 kPa 计?
$pV$ is constant: $100 \times 200 = p \times 100$, so $p = 200\ \text{kPa}$. Halving the volume doubles the pressure. · $pV$ 是恒定的:$100 \times 200 = p \times 100$,所以 $p = 200\ \text{kPa}$。体积减半使压强加倍。
Heating a gas in a sealed, fixed-volume can increases its pressure. · 在一个密封的、固定体积的罐中加热一种气体增加它的压强。
Hotter particles move faster and hit the walls harder and more often, so the pressure rises. · 更热的粒子运动更快并更猛、更频繁地撞击壁,所以压强上升。
Brownian motion 布朗运动
- Under a microscope, smoke specks in air jiggle along jerky, random paths.
- This is Brownian motion: the big specks are knocked about by fast, invisible air particles.
- It is strong evidence that matter really is made of moving particles.
Random hits from fast, invisible air particles push a smoke grain along a jerky, random path
布朗运动
- 在显微镜下,空气中的烟粒沿急动的、随机的路径抖动。
- 这是布朗运动(Brownian motion):大的烟粒被快速的、看不见的空气粒子撞来撞去。
- 它是物质真的由运动的粒子构成的有力证据。
快速、看不见的空气粒子的随机撞击,把烟粒推着沿急动的随机路径运动
Smoke specks seen under a microscope jiggle randomly. This is because: · 在显微镜下看到的烟粒随机抖动。这是因为:
Brownian motion: tiny fast air particles knock the larger smoke specks about, evidence for moving particles. · 布朗运动:微小的快速空气粒子把更大的烟粒撞来撞去,运动粒子的证据。
You've got it
- solid (fixed, vibrating) · liquid (close, sliding) · gas (far apart, fast)
- temperature = average kinetic energy of particles; absolute zero $= -273\ {}^{\circ}\text{C}$
- $T\,(\text{K}) = \theta\,({}^{\circ}\text{C}) + 273$
- gas pressure = particle hits per unit area; at constant temperature $pV = \text{constant}$
你掌握了
- 固体(固定,振动)· 液体(接近,滑动)· 气体(相距远,快速)
- 温度 = 粒子的平均动能;绝对零度 $= -273\ {}^{\circ}\text{C}$
- $T\,(\text{K}) = \theta\,({}^{\circ}\text{C}) + 273$
- 气体压强 = 每单位面积的粒子撞击;在恒定温度下 $pV = \text{constant}$