Transcript · English → Chinese
The Science of Trees and Touch
你以前摸过树。 你摸了它，然后走开了。
某种你看不见也感觉不到的变化 在你体内开始，就在
你的手触碰到那树皮的瞬间， 而且七天后它仍在继续。
而你所触摸的东西， 并不是你想象的那样。
没人会问的问题是：为什么？
无需服用任何化学药丸， 一棵树在对你的身体做些什么？
答案关乎木头 究竟是由什么制成的，
每个森林地表之下 正在发生着什么，
以及为什么地球上最古老的生命 一天也没有变老过。
把手伸到你的面前。 看着你的指尖。
你今天已经触摸了 成千上万种东西。
门把手、咖啡杯，
你的手机，你衣服的面料。
你从未触摸过它们中的任何一个。 在你的一生中，一次也没有。
你皮肤中原子周围的
电子云，排斥着你伸手触碰的 一切事物中的电子云。
电磁力在永远无法闭合的间隙中 产生排斥。
你所感受到的接触， 其实是穿过虚无空间的力。
你所感知过的每一种质感，
每一次握手，你用手掌 按压过的每一个表面？
都是电磁排斥力。
你的大脑将这种力解读为触觉。 但那个间隙一直都在。
所以，当你把手放在树上时，
你的皮肤并没有真正碰到树皮。
但确实有什么东西跨越了那个间隙。 并非通过接触，而是通过你们之间的 空气。
而跨越该间隙之物的物理原理， 是从来没人向你解释过的第一件事。
树木会向周围的空气中释放分子。 并非偶尔为之。
这些是挥发性有机化合物。
分子量足够低 且蒸汽压足够高，以至于
在常温常压下 从液态转化为气态。
这是一个物理学界限， 而非生物学界限。
分子能否悬浮于空气中 取决于分子间作用力，
即分子之间相互结合的紧密程度。
在低于一定的分子量 且高于一定的蒸汽压时，
分子就会逸散到气相中。
α-蒎烯、β-蒎烯、 D-柠檬烯、1,8-桉叶油素。
these molecules are light enough and loosely bound enough to float.
它们有一个名字， 叫做植物杀菌素，而这个词
其含义并非那些销售 精油的人想让你以为的那样。
这个词是由
一位名叫鲍里斯·托金的俄罗斯生物 学家 于1928年创造的，字面意思是
“被植物消灭”。
这些是化学防御武器。
树木制造它们是为了杀死细菌、 真菌
以及威胁树木生存的 昆虫。
树木并不是在释放令人愉悦的香气。
它正在对所有小到足以被 空气传播分子
摧毁的生物发动化学战争。
以下是起作用的物理原理。
一旦这些分子进入气相， 它们就会遵循
所有气体都遵循的规律。 即菲克扩散定律。
分子从高浓度区域 向低浓度区域移动
沿着梯度方向。
树木是源头，
树皮表面的浓度最高。
树木周围的空气 就是梯度场。
End of transcript · 534 words · machine translated
Original transcript (English)
You've touched a tree before. You touched it and walked away. Something you could not see and could not feel started inside your body the moment your hand met that bark, and it was still going seven days later. And the thing you touched is not what you think it is. The question nobody asks is why.
What is a tree doing to your body without a single chemical pill? The answer involves what wood is actually made of, what is happening underneath every forest floor, and why the oldest living thing on earth has never aged a single day. Hold your hand out in front of you. Look at your fingertips.
You have touched thousands of things today. A doorknob, a coffee cup, your phone, the fabric of your clothes. You have never touched a single one of them. Not once in your entire life. The electron clouds around the
atoms in your skin repel the electron clouds in everything you reach for. Electromagnetic force pushes back across a gap that never closes. What you feel as contact is force across empty space. Every texture you have ever known, every handshake, every surface you have pressed your palm against?
Electromagnetic repulsion. Your brain interprets the force as touch. But the gap is always there. So when you put your hand on a tree, your skin does not meet the bark. But something does cross that gap. Not through contact. Through the air between you.
And the physics of what crosses that gap is the first thing nobody ever explains. Trees release molecules into the air around them. Not occasionally. These are volatile organic compounds. Molecules with low enough molecular mass and high enough vapor pressure to transition from liquid to gas at ordinary temperatures and atmospheric pressure.
That is a physics threshold, not a biology one. Whether a molecule becomes airborne depends on intermolecular forces, how tightly the molecules grip each other. Below a certain molecular weight and above a certain vapor pressure, the molecule escapes into the gas phase.
Alpha Pinene, Beta Pinene, D Limonene, 1 8 Cineole. These molecules are light enough and loosely bound enough to float. They have a name, phytoncytes, and that word does not mean what people selling essential oils want you to think it means. It was coined in
1928 by a Russian biologist named Boris Tokin, and it literally translates to exterminated by the plant. These are chemical defense weapons. Trees manufacture them to kill bacteria, fungi, and insects that threaten the tree's survival.
The tree is not releasing pleasant aromas. It is waging chemical warfare on everything small enough to be destroyed by airborne molecules. Here is the physics that matters. Once these molecules enter the gas phase, they follow the same
rules every gas follows. Fixed law of diffusion. Molecules move from regions of high concentration to regions of low concentration along a gradient. The tree is the source, maximum concentration at the bark surface.
The air around the tree is the gradient field.
