自由膨胀中理想气体的熵变如何计算，既然Q=0？
How is entropy change computed for free expansion if Q=0?
自由膨胀不可逆且 Q=0，但熵是状态函数；可设想一条可逆等温膨胀连接相同初末态，ΔS=∫dQ_rev/T=nR ln(V2/V1)。不能用实际过程的 dQ 计算不可逆路径。
Free expansion is irreversible with Q=0, but entropy is a state function; use a reversible isothermal path between the same states: ΔS=nR ln(V2/V1). The actual dQ cannot be used.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #熵 #状态函数
为什么绝对零度（-273.15°C）只能无限逼近，却永远无法真正达到？
Why can absolute zero (−273.15 °C) only be approached but never actually reached?
热力学第三定律指出，任何有限步骤的制冷过程都无法把系统冷却到绝对零度。随着温度趋近零，可用的熵差和可利用的制冷“落差”都趋于消失，因此越接近零越难再降温。它是一条不可逾越的极限，而非单纯技术困难。
The third law of thermodynamics states that no finite sequence of cooling steps can bring a system to absolute zero. As temperature approaches zero, the available entropy differences and the cooling 'head' both vanish, making further cooling ever harder. It is a fundamental limit, not merely a technical difficulty.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
L. Masanes & J. Oppenheim,《A general derivation and quantification of the third law of thermodynamics》,Nature Communications 8,14538(2017)
L. Masanes & J. Oppenheim, 'A general derivation and quantification of the third law of thermodynamics', Nature Communications 8, 14538 (2017)
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1038/ncomms14538
#热力学第三定律 #绝对零度 #熵
吉布斯悖论如何揭示熵是广延量且需要量子统计？
How does Gibbs paradox reveal entropy extensivity and need quantum statistics?
经典理想气体混合两等同气体若直接得正混合熵会违反广延性（吉布斯悖论）；引入不可分辨性与 1/N! 修正后熵才广延，并指出经典力学中粒子不可分辨性实际源自量子全同性。
Classically mixing identical gases wrongly gives positive entropy (Gibbs paradox); adding 1/N! for indistinguishability restores extensivity and shows indistinguishability is ultimately quantum.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #吉布斯悖论 #统计力学
涨落-耗散定理把噪声和响应联系起来意味着什么？
What does the fluctuation-dissipation theorem mean?
它表明系统处于平衡时的自发涨落（噪声）与其对微扰的线性响应（耗散）由同一温度联系：越粘滞的响应，其热噪声越大。这是约翰逊噪声与电阻关系的来源。
It links equilibrium fluctuations (noise) to linear response (dissipation) at temperature T: stronger dissipative response implies larger thermal fluctuations—this underlies Johnson noise in resistors.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #涨落耗散 #噪声
液氦在极低温下为什么会变成“超流体”——能沿着杯壁自己爬出来流走？
Why does liquid helium become a 'superfluid' at very low temperature, even climbing the walls of its container and escaping?
在约 2.17 K 以下，部分氦-4 原子凝聚到同一个量子基态，形成具有零黏度的玻色–爱因斯坦凝聚成分。这种超流体没有任何黏性阻力，能沿极薄的液膜爬上容器壁、从杯口溢出。它是宏观尺度上直接显现的量子现象。
Below about 2.17 K a fraction of helium-4 atoms condenses into the same quantum ground state, forming a viscosity-free Bose–Einstein condensate component. With no viscous resistance, the superfluid creeps up container walls in an ultra-thin film and can overflow the rim. It is a quantum phenomenon visible at macroscopic scale.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
A. J. Leggett,《Quantum Liquids》(Oxford Univ. Press,2006),第2章(液氦超流)
A. J. Leggett, 'Quantum Liquids' (Oxford Univ. Press, 2006), Ch.2 (Superfluid helium)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780198526438 (2006)
#超流 #玻色-爱因斯坦凝聚 #液氦
加热的铁块为什么会由暗红变成黄白色？这和量子论的诞生有什么关系？
Why does heated iron glow from dull red to yellow-white, and what does that have to do with the birth of quantum theory?
物体温度越高，辐射的电磁波峰值波长越短，所以铁块先发红光，温度升高后峰值移向黄白色，这就是维恩位移定律。但经典物理完全无法解释黑体辐射的能量分布曲线，所谓"紫外灾难"迫使普朗克大胆假设：辐射能量只能以量子hv为单位一份份地发出。这一假设给出与实验完全吻合的公式，成为量子力学的起点，也直接启发了爱因斯坦后来解释光电效应。
The hotter an object, the shorter the peak wavelength of its radiation, so iron glows red first and shifts toward yellow-white as it heats — Wien's displacement law. But classical physics could not explain the blackbody spectrum at all, the "ultraviolet catastrophe," and this forced Planck to assume that energy is emitted only in discrete quanta hv. That hypothesis reproduced the data exactly, launched quantum mechanics, and directly inspired Einstein's later explanation of the photoelectric effect.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《费曼物理学讲义》第一卷（黑体辐射）
The Feynman Lectures on Physics, Vol. 1 (blackbody radiation)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-7382-0298-3 (2006 Pearson 版，原始版为1963-65 Addis
#黑体辐射 #维恩位移 #能量量子化
麦克斯韦妖真的能让热从冷处流向热处，从而推翻热力学第二定律吗？
Could Maxwell's demon really make heat flow from cold to hot and break the second law of thermodynamics?
麦克斯韦设想的小妖能辨认单个分子的速度并开关一道小门：把快分子放行到一边、慢分子留在另一边，无需做功就能制造温差。但深入分析后发现，妖精必须测量、记忆并擦除分子信息，而这些信息处理环节都不可避免要消耗能量、产生熵。把测量和存储的代价计入后，系统总熵并不会减少，热力学第二定律依然成立。
Maxwell imagined a tiny demon that recognizes individual molecular speeds and opens a trapdoor, sorting fast molecules to one side and slow ones to the other to build a temperature difference without work. Deeper analysis showed the demon must measure, remember and erase information about the molecules, and each of these steps inevitably costs energy and produces entropy. Once the price of information processing is included, total entropy never decreases and the second law stands.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《费曼物理学讲义》第一卷（麦克斯韦妖）
The Feynman Lectures on Physics, Vol. 1 (Maxwell's demon)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-7382-0298-3 (2006 Pearson 版，原始版为1963-65 Addis
#麦克斯韦妖 #信息熵 #热力学第二定律
什么是绝对零度？
What is absolute zero?
绝对零度约为 −273.15°C（0 K），是理论上分子热运动完全停止、不能再降温的最低温度，实际无法真正达到。
Absolute zero is about −273.15°C (0 K), the theoretical limit where molecular motion stops. It can be approached but never truly reached.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
Thomson（开尔文勋爵），《论绝对温标》，Philosophical Magazine 33 (1848)
Thomson (Lord Kelvin), 'On an Absolute Thermometric Scale', Philosophical Magazine 33 (1848)
#绝对零度 #热力学 #温度
为什么老式温度计和电熨斗里用两种金属片叠在一起感温？
Why do old thermometers and irons use two bonded metal strips to sense temperature?
不同金属的热膨胀系数不同，受热时一侧伸长更多，双金属片就会向膨胀小的一侧弯曲。把弯曲量标定为温度，就能做温度计；接上开关就能控温。
Different metals expand by different amounts when heated, so a bonded bimetallic strip curves toward the side that expands less. Calibrating that bend to temperature makes a thermometer, and attaching a switch lets it control heat.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热胀冷缩 #双金属 #热学
为什么把水滴到很烫的平底锅上，水滴会四处滚动而不马上蒸发？
Why does a water drop skitter around on a very hot pan instead of evaporating at once?
当锅面远超水的沸点，水滴底部瞬间汽化形成一层蒸汽垫，把水珠托起隔绝了直接接触。蒸汽隔热使蒸发变慢，水滴就能悬浮翻滚一阵，这叫莱顿弗罗斯特效应。
When the surface is far above water's boiling point, the drop's bottom flashes to vapor and forms a steam cushion that lifts it off direct contact. The vapor insulates and slows evaporation, so the drop skitters for a while; this is the Leidenfrost effect.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#相变 #蒸发 #热学
为什么绝对零度无法达到？
Why can absolute zero never be reached?
绝对零度约为零下 273.15 摄氏度，是理论上粒子热运动完全停止的温度。热力学第三定律指出，用有限步骤不可能把系统冷却到绝对零度。
Absolute zero, about minus 273.15 degrees Celsius, is the temperature at which particle motion would stop. The third law of thermodynamics says no finite process can cool a system all the way to absolute zero.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#绝对零度 #热力学第三定律 #低温
为什么保温瓶内胆要镀成亮银色？
Why is the inside of a thermos flask coated shiny silver?
银色光亮表面对热辐射反射率高，能把向内或向外的红外辐射反射回去，减少以辐射方式散失的热量。配合真空层，保温效果更强。
A shiny silver surface has high reflectivity for thermal radiation, bouncing infrared heat back instead of letting it escape, which cuts radiative heat loss. Combined with the vacuum layer, it boosts insulation.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#辐射 #反射 #热学
理想气体状态方程是什么？
What is the ideal gas law?
理想气体状态方程为 pV=nRT，其中 p 是压强、V 是体积、n 是物质的量、T 是温度、R 是常数。它描述了在分子相互作用可忽略时气体的宏观行为。
The ideal gas law is pV=nRT, where p is pressure, V is volume, n is amount of substance, T is temperature, and R is a constant. It describes gas behavior when molecular interactions are negligible.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#理想气体 #状态方程 #压强
熵到底是什么？为什么说孤立系统的熵只会增加？
What exactly is entropy, and why does it always increase in an isolated system?
熵衡量系统的混乱程度，更准确地说是：给定同一个宏观状态时，系统内部各种微观排列方式的数量。孤立系统总会自发走向微观状态数最多的那个方向，因此熵趋于增加，这就是热力学第二定律。热从高温流向低温、墨水在水中自动散开，都是熵增在日常生活里的体现。
Entropy measures disorder — more precisely, how many microscopic arrangements correspond to a given macroscopic state. An isolated system spontaneously moves toward the most numerous arrangements, so its entropy tends to grow; that is the second law of thermodynamics. Heat flowing from hot to cold and ink dispersing through water are everyday displays of increasing entropy.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《费曼物理学讲义》第一卷（熵）
The Feynman Lectures on Physics, Vol. 1 (entropy)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-7382-0298-3 (2006 Pearson 版，原始版为1963-65 Addis
#熵 #热力学第二定律 #混乱度
为什么被100摄氏度的蒸汽烫伤，常常比被同样温度的热水更严重？
Why does steam at 100°C often scald worse than boiling water at the same temperature?
因为蒸汽在皮肤表面凝结成水时，会释放出大量潜热：每克蒸汽凝结大约放出540卡热量，相当于把同质量的水再加热五百多度。这股额外的凝结热迅速传给皮肤，造成比热水更深的烫伤。潜热就是物质在相变时吸收或放出的那笔巨大的热量，它解释了很多"烫得不合理"的现象。
When steam condenses on skin, it releases latent heat — about 540 calories per gram, enough to heat the same mass of water more than 500 degrees more. This condensation heat dumps into the skin quickly and causes deeper burns than hot water. Latent heat is the large energy absorbed or released during a phase change, and it explains many surprisingly dangerous burns.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#潜热 #相变 #汽化
为什么两种金属受热膨胀快慢不同就能让指针动起来？
Why can two metals expanding at different rates move a pointer (bimetallic strip)?
双金属片由两种膨胀率不同的金属贴合而成，受热时一边伸长多、一边少，整片就会弯曲，从而推动指针或开关。
A bimetallic strip bonds two metals with different expansion rates; heating bends it because one side grows more than the other, moving a pointer or switch.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Halliday、Resnick 与 Walker，《物理学基础》（第10版）
Halliday, Resnick & Walker, 'Fundamentals of Physics' (10th ed.)
独立核验依据 · Independent verification: 核验依据 2 angusrobertson.com.au
#热膨胀 #双金属 #温度计
冰融化成水需要什么条件？
What does it take for ice to melt into water?
冰在 0 摄氏度、标准大气压下开始融化，融化时需要吸收热量来打破分子间的有序排列。这个过程中温度保持不变，直到全部变成水。
At 0 degrees Celsius and standard pressure, ice begins to melt, absorbing heat to break its ordered molecular arrangement. The temperature stays constant during melting until all the ice becomes water.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#相变 #融化 #潜热
热力学第二定律说明了什么？
What does the second law of thermodynamics tell us?
热力学第二定律指出热量不能自发地从低温物体传到高温物体，孤立系统的熵只增不减。它解释了为什么时间有方向、为什么永动机不可能。
The second law states heat cannot spontaneously flow from cold to hot, and an isolated system's entropy never decreases. It explains the arrow of time and why perpetual-motion machines are impossible.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学第二定律 #熵增 #方向性
为什么往暖水瓶倒完开水，瓶塞有时会自己蹦出来？
Why does a thermos stopper sometimes pop out by itself after you pour in hot water?
倒入热水后瓶内空气被加热膨胀，若瓶塞盖得严实，内部气压高于外界，就会把塞子顶出。留一点缝隙让多余气体逸出就能避免。
Pouring in hot water heats and expands the trapped air; if the stopper seals tightly, the higher internal pressure pushes the cork out. Leaving a small gap lets the excess gas escape and prevents it.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#气压 #膨胀 #热学
为什么气球在冷的地方会变小？
Why does a balloon shrink in a cold place?
温度降低时气体分子运动变慢、挤得更近，体积随温度下降而收缩，这叫查理定律（定压下体积与温度成正比）。
Cooling slows gas molecules so they crowd closer; at constant pressure the volume shrinks with temperature (Charles's law).
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Halliday、Resnick 与 Walker，《物理学基础》（第10版）
Halliday, Resnick & Walker, 'Fundamentals of Physics' (10th ed.)
独立核验依据 · Independent verification: 核验依据 2 angusrobertson.com.au
#查理定律 #气体 #体积
为什么同样室温下，湿手摸金属比摸木头感觉更凉？
Why does metal feel colder than wood at the same room temperature when your wet hand touches them?
金属导热快，会迅速把手指的热量导走，皮肤温度下降快所以觉得凉；木头导热慢，热量积聚在接触面，感觉没那么凉。差别来自导热率而非温度。
Metal conducts heat quickly and draws warmth from your finger fast, so the skin cools rapidly and feels cold; wood conducts poorly, leaving heat at the contact surface, so it feels less cold. The difference is conductivity, not temperature.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#导热 #热传递 #热学
为什么长长的铁轨之间要留有小缝隙？
Why are small gaps left between long sections of railway track?
金属受热会膨胀、受冷会收缩，夏天铁轨伸长若无处可去就会弯曲变形（胀轨）。预留缝隙给热膨胀留出空间，避免轨道扭曲出事故。
Metal expands when hot and contracts when cold; in summer the rails lengthen and, with no room to go, would buckle. The gaps give thermal expansion space and prevent the track from warping dangerously.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热胀冷缩 #膨胀 #热学
为什么功可以轻易地全部变成热，热却不能全部变成功？
Why can work easily become heat, but heat cannot be fully converted into work?
摩擦生热这类过程把有序的机械能彻底打散成无序的分子热运动，容易且不可逆。而要把热全变成有用功，需要把所有分子运动完美有序化，热力学第二定律（开尔文表述）禁止这种 100% 转换。总有一部分废热必须排向低温热源。
Friction turns ordered mechanical energy into disordered molecular motion, easily and irreversibly. Converting heat 100% into useful work would require perfectly ordering all molecular motion, which the second law (Kelvin–Planck statement) forbids. Some waste heat must always be rejected to a colder reservoir.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04 · 3 条独立证据
来源 · Source
Çengel & Boles,《Thermodynamics: An Engineering Approach》(第9版),第6章(热力学第二定律)
Çengel & Boles, 'Thermodynamics: An Engineering Approach' (9th ed.), Ch.6 (Second law of thermodynamics)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-259-27989-8 (9th ed., McGraw-Hill) · 核验依据 2 ISBN 9781260116106 (2018) · 核验依据 3 ISBN 9780665590955 (2002)
#热力学第二定律 #不可逆 #卡诺极限
夏天出汗为什么能让人凉快？
Why does sweating cool you down on a hot day?
汗水从液态变成水蒸气需要吸收热量，这部分汽化潜热正是从皮肤表面带走的。皮肤表层那些能量较高的水分子逃逸到空气中时，会把身体的热量一并带走，剩下的皮肤温度随之下降。空气越干、温度越高、风越大，蒸发越快，降温效果也越明显，洒水和吹风扇都是同一道理。
Turning liquid sweat into vapor requires heat, and that latent heat of vaporization is drawn from the skin. As the most energetic water molecules escape into the air they carry body heat away, lowering the skin's temperature. Drier air, higher temperature and wind all speed up evaporation and the cooling, which is why misting and fans work.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#蒸发 #潜热 #降温
空调和冰箱是怎么把热从冷的地方"搬"到热的地方的？
How do air conditioners and refrigerators move heat from a cold place to a hot one?
热量不会自发从低温流向高温，但外界做功可以强迫它逆着走。制冷剂在蒸发器里蒸发吸热，把室内的热带走；随后压缩机把它压缩成高温高压气体，在冷凝器里向室外放热并重新液化，如此循环往复。每消耗一份电功，热泵搬走的热量比功还多，所以它的制冷效率可以超过百分之百。
Heat never flows from cold to hot by itself, but external work can force it to. Refrigerant evaporates in the evaporator, absorbing heat from inside; the compressor then squeezes it into hot, high-pressure gas that condenses in the condenser, releasing heat outside, and the cycle repeats. Each unit of work moves more heat than the work itself, which is why a heat pump can be more than 100% efficient.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《费曼物理学讲义》第一卷（热机）
The Feynman Lectures on Physics, Vol. 1 (heat engines)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-7382-0298-3 (2006 Pearson 版，原始版为1963-65 Addis
#热泵 #制冷循环 #压缩机
熵增和时间之箭有什么关系？
What is the link between entropy increase and the arrow of time?
宏观过程（混合、扩散、衰老）之所以只朝一个方向发生，是因为初始低熵状态后系统的微观状态数倾向于增大。时间的心理与热力学之箭被认为根源于宇宙极低的初始熵。
Irreversible macroscopic processes reflect the tendency from a low-entropy past toward higher entropy; the thermodynamic arrow is tied to the universe's exceptionally low initial entropy.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #时间之箭 #熵
为什么保温瓶能让热水长时间不凉？
Why does a thermos keep water hot so long?
保温瓶用真空层隔断传导和对流，内胆镀银反射热辐射，使三条传热途径（传导、对流、辐射）都被大幅削弱，热量散失极慢。
A vacuum layer blocks conduction and convection, and a silvered lining reflects radiation, so all three heat-transfer modes are suppressed and cooling is very slow.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #隔热 #传热
冰箱明明在把里面变冷，背后散热器却向外放热，而且排出的热量为什么比从里面取出的还多？
A fridge cools its inside, yet its back radiator releases heat—and why is that rejected heat more than what was removed from inside?
冰箱是热泵，压缩机做功把内部热量搬到外部。根据能量守恒，外面放出的热量等于从内部吸出的热量加上压缩机消耗的电能。所以散热器排出的总热量必然大于内部被取走的热量，这正是它背后会发热的原因。
A refrigerator is a heat pump: the compressor does work to move heat from inside to outside. By energy conservation, the heat dumped outside equals the heat extracted from inside plus the electrical work consumed. The radiator therefore rejects more heat than was removed from the interior, which is why it feels warm.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-10-04 · 3 条独立证据
来源 · Source
Çengel & Boles,《Thermodynamics: An Engineering Approach》(第9版),第6章(制冷与热泵)
Çengel & Boles, 'Thermodynamics: An Engineering Approach' (9th ed.), Ch.6 (Refrigerators and heat pumps)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-259-27989-8 (9th ed., McGraw-Hill) · 核验依据 2 ISBN 9781260116106 (2018) · 核验依据 3 ISBN 9780665590955 (2002)
#制冷循环 #热力学第二定律 #热泵
为什么突然往厚玻璃杯里倒开水，杯子有时会炸裂？
Why does a thick glass sometimes crack when you pour boiling water into it suddenly?
内壁骤热迅速膨胀，而外壁还冷、来不及跟着胀，内外胀缩不均产生很大热应力。当应力超过玻璃强度，杯子就从薄弱处裂开。
The inner wall heats and expands suddenly while the outer wall is still cold and cannot expand with it, creating large thermal stress from uneven expansion. When the stress exceeds the glass strength, it cracks at its weakest point.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热应力 #膨胀 #热学
麦克斯韦妖为什么最终不违反热力学第二定律？
Why doesn't Maxwell's demon ultimately violate the second law?
妖要获取并擦除关于分子的信息，而根据兰道尔原理，擦除一比特信息至少耗散 kT ln2 的热量，它付出的熵代价正好抵消（或超过）它造成的熵减。
The demon must acquire and erase information; Landauer's principle says erasing one bit costs at least kT ln2 of heat, canceling the entropy decrease it creates.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #麦克斯韦妖 #信息
负温度为什么比正温度更热？
Why is a negative temperature hotter than any positive temperature?
当系统能级有上限（如自旋系统）且高能级占据多于低能级时，玻尔兹曼分布给出 1/T<0，即负温度。负温度系统在能量上比任何正温度系统更高，会向正温度系统放热。
For bounded-energy systems (e.g. spins) with population inversion, 1/T<0 so T is negative; such systems have higher energy than any positive-T system and donate heat to them.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #负温度 #粒子数反转
什么是热寂说？
What is the heat death of the universe?
若宇宙持续膨胀且孤立，所有温差终将抹平，无法再做有用功，达到最大熵的近平衡态；这是一种基于熵增的宇宙学结局猜想，非定论。
If the universe keeps expanding as an isolated system, all temperature differences vanish and no work can be extracted—a maximal-entropy equilibrium. It is a speculative thermodynamic end, not settled.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #热寂 #宇宙学
为什么温度不可能降到绝对零度，也就是零下273.15摄氏度？
Why can nothing ever be cooled to absolute zero, -273.15°C?
绝对零度对应热运动的极限，所有粒子都处于能量最低的量子基态。但越接近绝对零度，每一步降温需要抽走的能量就越难以获得，根据热力学第三定律，任何有限次数的操作都无法真正到达这个极限。科学家已经用激光冷却等方法把原子降温到比绝对零度只高十亿分之一开尔文，但绝对零度本身始终无法到达。
Absolute zero is the limit of thermal motion, where every particle sits in its lowest-energy quantum state. But the closer you get, the harder it is to extract the remaining energy, and the third law of thermodynamics says no finite sequence of steps can reach the limit. Laser cooling has brought atoms to within a billionth of a kelvin of absolute zero, but the point itself remains forever out of reach.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#绝对零度 #第三定律 #激光冷却
相变中的临界现象为什么会出现标度律？
Why do scaling laws appear at critical phase transitions?
在临界点关联长度趋于无穷，系统丧失特征尺度，物理量按幂律依赖参数（如序参量∝(Tc-T)^β）；这种普适性由重整化群描述，与微观细节无关。
At a critical point the correlation length diverges, removing a characteristic scale, so quantities follow power laws (e.g. order parameter ∝ (Tc−T)^β); universality is explained by the renormalization group.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Wilson，《重正化群与临界现象》，Reviews of Modern Physics 55 (1983)
Wilson, 'The Renormalization Group and Critical Phenomena', Reviews of Modern Physics 55 (1983)
独立核验依据 · Independent verification: 核验依据 1 INSPIRE 标识 10.1103/RevModPhys.55.583：The renormalization
#热力学 #临界现象 #重整化
为什么夏天用扇子扇风，人会觉得凉快？
Why does fanning yourself with a fan feel cooler in summer?
扇风加快皮肤表面空气流动，促进汗液蒸发，而蒸发要吸收身体的热量。同时带走贴近皮肤的热空气层，增强对流散热，所以感到凉快。
Fanning speeds air flow over the skin and promotes sweat evaporation, which draws heat from the body. It also sweeps away the warm air layer next to the skin, boosting convective cooling, so you feel cooler.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#蒸发 #对流 #热学
冰箱是怎么制冷的？
How does a refrigerator keep things cold?
冰箱里的制冷剂在管道里压缩变热、膨胀变冷，循环时把箱内热量“搬”到箱外，于是里面变冷。
A refrigerant is compressed (hot) then expanded (cold) in a loop, carrying heat from inside the box to the outside, so the interior stays cold.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Halliday、Resnick 与 Walker，《物理学基础》（第10版）
Halliday, Resnick & Walker, 'Fundamentals of Physics' (10th ed.)
独立核验依据 · Independent verification: 核验依据 2 angusrobertson.com.au
#制冷 #制冷剂 #循环
为什么热机不可能把燃料的热能百分之百变成有用功？
Why can't a heat engine convert all the heat it takes in into useful work?
任何热机要循环运转，都必须从高温热源吸热，同时向低温热源排出一部分废热，否则无法回到初始状态。卡诺证明：即使在最理想的循环中，效率上限也只由两个热源的温度决定，效率等于1减去低温温度除以高温温度。要达到百分之百的效率，必须有温度为零下273.15摄氏度的冷源，而这不可能实现，所以效率永远小于1。
To run in a cycle, every heat engine must absorb heat from a hot reservoir and reject some heat to a cold reservoir, or it could never return to its starting state. Carnot proved that even the ideal cycle has an efficiency capped by the two reservoir temperatures: efficiency equals 1 minus the cold temperature over the hot temperature. Reaching 100% would require a cold reservoir at -273.15°C, which cannot exist, so real efficiency always falls short of 1.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《费曼物理学讲义》第一卷（卡诺循环）
The Feynman Lectures on Physics, Vol. 1 (the Carnot cycle)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-7382-0298-3 (2006 Pearson 版，原始版为1963-65 Addis
#卡诺循环 #热机效率 #热力学第二定律
为什么保温瓶能让热水一夜不凉?真空里没有东西怎么隔热?
How do thermoses keep water hot overnight — how can empty space block heat?
热量跑路有三条路:传导、对流、辐射。保温瓶全部封死:夹层抽成真空,没有物质就没法传导和对流;镀银的内壁像镜子把辐射反射回去;瓶口用软木塞堵住最后一道。三条路都断了,热水自然撑过一整夜。同一结构反过来也保冷,所以它装冰水同样管用。
Heat escapes three ways: conduction, convection, radiation. Thermoses block all: vacuum between walls leaves nothing to conduct or convect; silvered walls mirror radiation back; a cork seals the neck. With every route cut, hot water survives the night — flip the design and it holds ice just as well.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《十万个为什么》第六版物理分册,少年儿童出版社,2013
Ten Thousand Whys: Physics volume, 6th ed., Juvenile and Children Publishing House, 2013
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-7-5324-9328-9 · 核验依据 2 ISBN 9787532493289
#保温瓶 #真空隔热 #热传递
为什么雪人往往在晴天里从表面先化，而不是一下子全塌？
Why does a snowman melt from its surface first on a sunny day rather than collapsing all at once?
阳光和空气先加热雪的表面，表层达到熔点后融化成水并带走潜热，内部因导热慢仍保持低温。于是融化由外向内逐步推进，而不是整体同时化。
Sunlight and air heat the snow's surface first; once the outer layer reaches its melting point it turns to water and carries away latent heat, while the inside stays cold because heat conducts slowly. Melting thus proceeds from outside in, not all at once.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#融化 #导热 #热学
冰箱怎么把热“搬”到屋子外面？
How does a fridge move heat to the outside?
冰箱用压缩机让制冷剂在管内反复变液和变气，在内部吸热、在背后放热，把热量搬到房间里。
A compressor cycles a fluid between liquid and gas, soaking heat inside and dumping it out the back.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《十万个为什么》第六版物理分册,少年儿童出版社,2013
Ten Thousand Whys: Physics volume, 6th ed., Juvenile and Children Publishing House, 2013
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-7-5324-9328-9 · 核验依据 2 ISBN 9787532493289
#制冷 #热力学 #热机
在高原上烧水，为什么往往不到100°C就“开了”，可食物却更难煮熟？
At high altitude water often 'boils' below 100°C, so why does food then take longer to cook?
沸点取决于液面上方的气压，海拔越高气压越低，水达到沸腾所需的温度也越低。但食物熟化靠的是温度，温度不够高时分子反应慢，所以同样的火力下反而更难煮透。
The boiling point depends on the pressure above the liquid; higher altitude means lower pressure, so water boils at a lower temperature. Cooking depends on temperature, and at a lower temperature the chemical changes in food proceed more slowly, so it actually takes longer to cook through.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-10-04 · 3 条独立证据
来源 · Source
Çengel & Boles,《Thermodynamics: An Engineering Approach》(第9版),第3章(纯物质相变)
Çengel & Boles, 'Thermodynamics: An Engineering Approach' (9th ed.), Ch.3 (Phase change of pure substances)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-259-27989-8 (9th ed., McGraw-Hill) · 核验依据 2 ISBN 9781260116106 (2018) · 核验依据 3 ISBN 9780665590955 (2002)
#沸点 #气压 #高原
冰块在温水里为什么会化？
Why does ice melt in warm water?
温水里的水分子动得快，撞到冰时把能量分给冰里的分子，冰得到能量后排列变乱、变成流动的水，于是冰块慢慢变小。
Warm molecules move fast and bump energy into the ice; its molecules loosen their neat arrangement and become flowing water, so the ice shrinks.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #熔化 #热
为什么空调和冰箱都要用电才能把热量搬走？
Why do fridges and AC need electricity to move heat?
它们不是凭空消灭热量，而是用压缩机做功把热量从冷处泵到热处；根据热力学第二定律，把热从低温搬到高温必须消耗外界功。
They don't destroy heat; a compressor does work to pump heat from cold to hot. The second law requires external work to move heat uphill in temperature.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #制冷 #第二定律
温度是什么？
What is temperature?
温度表示物体冷热程度的物理量，反映内部粒子平均运动的剧烈程度。温度越高，粒子运动越剧烈，我们摸起来就越烫。
Temperature is a measure of how hot or cold an object is, reflecting the average vigor of its internal particles. Higher temperature means faster particle motion and a hotter feel to the touch.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#温度 #热 #粒子运动
热力学第一定律是什么？
What is the first law of thermodynamics?
热力学第一定律就是能量守恒在热现象中的表达：系统吸收的热量等于内能增加加上对外做的功。能量既不会凭空产生，也不会凭空消失。
The first law of thermodynamics is energy conservation applied to heat: heat added to a system equals its increase in internal energy plus the work it does. Energy is neither created nor destroyed.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学第一定律 #能量守恒 #内能
把铁块在炉火里越烧越热，它为什么先变暗红、再橙黄、最后接近白亮？
As a piece of iron is heated hotter and hotter, why does it glow from dim red to orange to nearly white?
受热物体辐射的峰值波长随温度升高而变短，这是维恩位移定律。温度低时峰值在红外、可见光只漏出红色；温度高时峰值移到更短波长，红橙黄绿蓝都变强，混合起来看着就发白。
The peak wavelength of a hot object's radiation shifts to shorter values as temperature rises, described by Wien's displacement law. At low temperature the peak is in the infrared and only red leaks into visible light; at high temperature the peak moves shorter, so more colors appear and the glow looks white.
难度 入门 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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M. Planck,《Über das Gesetz der Energieverteilung im Normalspectrum》,Annalen der Physik 309,553(1901)
M. Planck, 'On the Law of Distribution of Energy in the Normal Spectrum', Annalen der Physik 309, 553 (1901)
独立核验依据 · Independent verification: 核验依据 1 INSPIRE 标识 inspire:1227869：On the Law of Distribution of
#黑体辐射 #维恩位移定律 #热辐射
为什么冬天对着外面哈气，会看到一团白气？
Why do you see a puff of white breath when you exhale outside in winter?
呼出的温暖水蒸气遇到冷空气迅速降温，达到露点后凝结成无数微小水滴，悬浮在空气中形成可见的白雾。那不是气体本身，而是细小液滴。
Warm vapor in your breath cools rapidly in cold air and, reaching its dew point, condenses into countless tiny droplets suspended as a visible mist. It is not the gas itself but fine liquid drops you see.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
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秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#凝结 #露点 #热学
为什么有风的时候衣服干得更快？
Why do clothes dry faster when it is windy?
风把衣服表面刚蒸发出来的湿空气吹走，让干空气不断补位，水分就能更快变成水蒸气跑掉。
Wind carries away the humid air right above the clothes, letting dry air take its place so water evaporates faster.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Halliday、Resnick 与 Walker，《物理学基础》（第10版）
Halliday, Resnick & Walker, 'Fundamentals of Physics' (10th ed.)
独立核验依据 · Independent verification: 核验依据 2 angusrobertson.com.au
#蒸发 #风 #干燥
为什么水加热到一定温度会沸腾？
Why does water boil when heated to a certain temperature?
水被加热时内部汽化越来越剧烈；在标准大气压下，温度达到100摄氏度时，水的饱和蒸气压等于大气压，气泡能在液体内部形成并突破液面，这就是沸腾。高山上气压低，水的沸点也会相应降低。
As water warms, internal vaporization intensifies. At standard pressure, when it reaches 100 degrees Celsius, water's saturated vapor pressure equals the air pressure and bubbles form and burst through the liquid; that is boiling. At high altitudes the lower pressure lowers the boiling point.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#沸点 #沸腾 #汽化
热传递有哪几种方式？
What are the ways heat is transferred?
热传递主要有三种方式：传导是直接接触传热，对流靠流体流动带走热量，辐射则以电磁波形式直接发射热量。太阳就是通过辐射把热送到地球的。
Heat transfers mainly in three ways: conduction through direct contact, convection by moving fluids, and radiation by electromagnetic waves. The Sun warms Earth by radiation.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
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秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热传导 #对流 #辐射
为什么温度计里的水银柱或酒精柱会随着冷热升降？
Why does the mercury or alcohol column in a thermometer rise and fall with temperature?
液体受热体积膨胀、遇冷收缩，在细玻璃管里液柱高度就随体积变化而升降。管越细，同样的体积变化表现出的高度变化越明显，便于读数。
Liquids expand when heated and contract when cooled, so the column height in a thin glass tube changes with volume. The narrower the tube, the larger the visible height change for the same volume change, making reading easier.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
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秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热胀冷缩 #体积 #热学
为什么物体会热胀冷缩？
Why do objects expand when heated and contract when cooled?
温度升高时，物体内部分子运动加剧、间距变大，整体体积膨胀；温度降低时分子运动减弱、间距缩小，体积收缩。这就是热胀冷缩。
When heated, molecules inside move more vigorously and spread apart, so the object expands; when cooled, they move less and come closer, so it contracts. This is thermal expansion and contraction.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热胀冷缩 #分子 #体积
为什么热量只会从热的地方流向冷的地方？
Why does heat only flow from hot to cold?
因为总体更可能的微观状态是能量分散而不是集中；热量从热到冷会大大增加系统可实现的微观排列数，也就是熵增，所以方向几乎不可逆。
Because dispersed energy has vastly more possible microscopic arrangements; heat flowing hot→cold raises entropy, and the reverse is astronomically unlikely.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#热力学 #熵 #第二定律
为什么金属摸起来比木头更凉？
Why does metal feel colder than wood at the same temperature?
金属导热快，会迅速把手上的热量带走，所以感觉凉；木头导热慢，热量留在皮肤附近，感觉不凉。
Metal conducts heat quickly and pulls warmth from your hand, feeling cold. Wood conducts poorly, so heat stays near your skin and it feels neutral.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Halliday、Resnick 与 Walker，《物理学基础》（第10版）
Halliday, Resnick & Walker, 'Fundamentals of Physics' (10th ed.)
独立核验依据 · Independent verification: 核验依据 2 angusrobertson.com.au
#导热 #温度 #触感
为什么炎热夏天远处的柏油路看起来像有水波在晃动？
Why does distant asphalt on a hot summer day look like it has rippling water on it?
路面被晒得滚烫，贴近地面的空气密度低、折射率小，上层较密。光线穿过时发生弯曲，把天空折射到地面附近，看起来像反光的水，其实也是蜃景。
The baked road heats the air just above it, making it less dense with a lower refractive index than the layer above. Light bends through this gradient and refracts the sky down to the ground, looking like reflective water; it is again a mirage.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#折射 #蜃景 #热学
为什么蒸东西时锅盖内侧会挂满水珠，还不停滴落？
Why do droplets form and drip from the inside of a lid while steaming food?
锅内水蒸气上升到较凉的锅盖遇冷凝结成水珠，越积越大直到重力超过表面附着力就滴落。这也是自然界云变成雨的微型版本。
Steam rising in the pot hits the cooler lid and condenses into droplets that grow until gravity overcomes surface adhesion and they drip. It is a miniature version of clouds forming rain.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
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秦允豪,《热学》,高等教育出版社,2011
Qin Yunhao, Thermal Physics, Higher Education Press, 2011
#凝结 #相变 #热学
为什么冰块会变成水,水放在冰箱里又变回冰?
Why does ice melt into water, then freeze again in the freezer?
水和冰是一对好朋友:暖和时,冰里的分子松开手,变成流动的水;冰箱里很冷,分子们重新排好队,又变回硬硬的冰。变来变去都是水呀。
Water and ice are best friends in two outfits: warm rooms make molecules let go and flow as water; freezer cold lines them up again into hard ice. Changing back and forth, they are always the same water.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
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《十万个为什么》第六版物理分册,少年儿童出版社,2013
Ten Thousand Whys: Physics volume, 6th ed., Juvenile and Children Publishing House, 2013
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-7-5324-9328-9 · 核验依据 2 ISBN 9787532493289
#冰与水 #融化 #结冰
水能变成哪三种不一样的样子?冰化了还能变回水吗?
What three different forms can water take, and can ice turn back into water?
平常的水会流动,是液体。放进冰箱冻一冻,水变成硬硬的冰,成了固体。烧开的水冒出白蒙蒙的水汽,里面藏着水蒸气,它是气体。温度一变,水就能在固体、液体、气体三种样子之间变来变去,冰化了还会变回水呢。
Everyday water flows, so it is a liquid. Put it in the freezer and it becomes hard ice, a solid. Boil it and white mist rises from the pot, hiding water vapor, which is a gas. When temperature changes, water switches among solid, liquid, and gas; melted ice turns right back into water.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 来源待核验 · Source pending review
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出处备注：作者 / 书名 / 版次 / 出版社 / 年份齐备，仅缺独立比对证据；已在可信度报告单列披露，不再重复核验。
《神奇校车·水的故事》,贵州人民出版社,2005
The Magic School Bus at the Waterworks, Guizhou People's Publishing House, 2005
#水的三态 #冻结融化 #水蒸气