🔥 燃烧与灭火：火三角与拆三角🔥 Combustion & Fire Safety: the Fire Triangle

上一片氧化还原里，电子搬家上演了激烈的一幕。燃烧，就是其中最热闹的一种。这一片不只看热闹——看懂火三角，你就能在关键时刻拆掉它。 Last leaf, redox showed electrons changing hands. Combustion is the most dramatic version of that show. This leaf is not just about watching flames — read the fire triangle, and you will know exactly how to tear it apart.

第 1 步：火三角——三个条件，缺一不可Step 1: The fire triangle — all three, or nothing

先弄明白：东西为什么能烧起来？First things first: why does anything burn at all?

火三角：可燃物、氧气、着火点 — 燃烧需要三个条件同时到场：有东西可烧（可燃物——木柴、油、酒精）、有氧气（空气里就管够）、温度升到着火点（一根火柴就能让纸到达它的着火点）。三个角撑起同一个三角形——少一个，火就塌了。潮湿的木头点不着，就是水分蒸发抢走了热量。 Burning needs all three at once: something to burn (fuel — wood, oil, alcohol), oxygen (the air supplies plenty), and enough heat to reach the ignition temperature (one match gets paper there). The three sides hold up one triangle — remove one and the fire collapses. That is why damp wood refuses to light: evaporating water steals the heat.

既然三个角缺一不可，灭火的答案就很简单了——If all three sides are required, the answer writes itself —

第 2 步：灭火，就是拆掉任意一角Step 2: Fighting fire = tearing off any one side

油锅起火：盖锅盖，别浇水 — 拆掉一个角，火就灭：盖锅盖、盖湿抹布=隔绝氧气；浇水、喷水=把温度降到着火点以下；砍隔离带、搬走柴草=隔离可燃物。但有一件事绝对不要做：往着火的油锅里浇水。水碰到滚烫的热油会瞬间汽化，把燃烧的油炸得满天飞。油锅起火，稳稳盖上锅盖就好。 Tear off one side and the fire dies: a lid or a wet cloth cuts off oxygen; water cools below the ignition point; a firebreak removes the fuel. But never do one thing: throw water into a burning oil pan. Water hitting hot oil flashes into steam and blasts burning oil everywhere. For an oil pan fire, the lid is the hero.

那是不是所有火都能用水浇？远远不是——So can water fight every fire? Far from it —

第 3 步：不同火情，用不同的灭火器Step 3: Different fires, different extinguishers

灭火器四步：提、拔、握、压 — 电器起火先断电，用干粉或二氧化碳灭火器——水导电，会触电；油类火灾用干粉或泡沫——水会让热油飞溅；普通的木头、纸张起火，水就可以。灭火器四步口诀：提、拔、握、压——最重要的一步是**对准火焰根部**，因为火是在底部烧起来的，对着火苗尖喷等于白喷。 For electrical fires, cut the power first, then use a dry-powder or CO₂ extinguisher — water conducts and can shock you. For oil fires, dry powder or foam — water makes hot oil spit. For ordinary wood and paper, water is fine. Four steps for an extinguisher: lift, pull, hold, press — and the step that matters most is **aiming at the base**, because that is where the burning happens; spraying the tips of the flames does nothing.

🎮 你来当灭火员（60 秒）🎮 Your turn: firefighter on duty (60 seconds)

火三角会背了，来真的——4 个火情现场，选对灭火方式，错了会告诉你后果。You know the triangle — now face 4 real scenes and pick the right move. Pick wrong and we show you what happens next.

一句话记住它：燃烧 = 可燃物 + 氧气 + 温度达到着火点；灭火 = 拆掉任意一角（隔氧、降温、搬走燃料）。 Remember it in one line: fire = fuel + oxygen + heat above ignition; firefighting = remove any one side (cut oxygen, cool it down, or take the fuel away).

火三角：可燃物、氧气、着火点，缺一不可Fire triangle: fuel, oxygen, ignition temperature — all three required 三种拆法：隔氧（盖锅盖）、降温（浇水）、隔离可燃物（砍隔离带）Three ways to break it: cut oxygen (lid), cool down (water), remove fuel (firebreak) 油锅起火绝不浇水（会爆燃）；电器起火先断电；灭火器对准火焰根部（提拔握压）Never water on an oil fire (it explodes into steam); cut power on electrical fires; aim at the base (lift–pull–hold–press)

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内容参考 OpenStax 等公开教材，多来源核对 · AI 生成、人工审核 · 发现错误欢迎指正，帮这片叶子长得更好。 Based on OpenStax and other open textbooks, cross-checked across sources · AI-generated, human-reviewed · Spotted a mistake? Tell us — help this leaf grow.