Wouldn't it be great if we could be invisible? Ha, right? I mean, we could spy on people without being noticed and do whatever we want without being held responsible. Now, magicians have figured out how to utilize full-sized mirrors to bend light in order to create disappearing illusions. Scientists have created metamaterials to guide rays of light around tiny, two-dimensional objects. Cameras can also film what is behind you and project the image so you appear invisible from the front. However, none of these options can make an object as large as a person appear invisible for all angles and distances while its moving. But if you are truly invisible, as in from within, here are a few problems you may not have thought about before. To move around undetected by other people, you would have to be totally naked. Even if it's freezing outside! You can't carry anything, including your wallet and keys, otherwise people would just see your wallet and keys floating around. Drivers and people on the street can't see you either, therefore they can and will run into you at some point. Oh, and you better not wear any perfume or make any noise breathing, otherwise they'll know you're there. And, just because you start off invisible, doesn't mean you'll stay that way. What if someone accidentally spills scolding hot coffee on you? And what if it rains? But if you think only liquid can make you visible, you're wrong. Dust consists of dead skin cells from humans, soil particles, and fibers from clothes made from cotton and other materials. Dust sticks to the moisture on our skin when we sweat and the tiny hairs on our skin when we are dry. So, even if you are invisible, dust would still land on every part of you. We usually don't notice the dust on our skin because we can't see a thin layer of dust on top of our skin color. But, if you're invisible, people would see a human-shaped blob of dust walking around with extremely dirty soles. Gross! What do you think the world looks like if you are invisible? Well, the answer is nothing. The reason you can't see in the dark is because there is no light. To see an apple, light has to hit the apple and return it to your eyes. Then, the retinas in your eyes catch the light reflection for your brain to interpret into the image of an apple. If you're invisible, then, by definition, light would travel through you or around you instead of bouncing off you for people to see. But that means that retinas in your eyes are not catching the light, either. Therefore, your brain has nothing to interpret into an image. Can you see your reflection without a mirror to stop the light? No. So, when you can't be seen by others, you also cannot see. Ouch! Now, have you given any thought as of whether the invisibility is permanent? If it is, how can you receive medical treatment from a doctor if you're injured? The doctor wouldn't know where to apply ointments or bandages because they cannot access your injury. For that matter, you can't see it either. I mean, what if you have an illness or an infection? How can the doctor diagnose you without being able to see the color change or inflammation? And what if everyone is permanently invisible? Well, think about how boring the world would be without seeing people on the streets, on TV, or at home on your computer like right now. It's lonely being invisible. Now, which superpower physics lesson will you explore next? Shifting body size and content, super speed, flight, super strength, immortality, and invisibility.
如果我们能隐身 这难道不好么? 对么? 我是说,我们可以偷窥别人而且不会被发现 可以做我们想做的任何事 而且不用负责任 现在,魔术师研究出了 如何让真实尺寸的镜子来弯曲光线 来产生隐身的假象 科学家创造出了一种“超材料” 在极小的二维空间的物品中 可以引导光线的方向 相机可以拍到你身后的东西 并映射出图片 所以,从前面是看不见你的 然而,所有的这些操作 都无法使人这么大的物品 在他移动的时候的隐形, 从各个角度和不同的距离来看 但是,如果你真的隐形了 完全做到了隐身 有一些问题 你之前可能从来没想到过 为了行动的时候不被别人察觉 你必须要完完全全的赤裸 即使外面非常的冷 你不能带任何东西 包括你的钱包和钥匙 否则人们就会看见 你的钱包和钥匙飘来飘去 街上的司机和行人也都看不见你 因此他们可能会撞上你 对了,你最好不要喷香水 或者大声喘气 否则,他们就会知道你在那里 而且,就算你开始的时候是隐身的 并不代表你会永远隐身 如果有个人不小心 把热咖啡洒到了你身上,你会怎么样? 如果下雨了呢?你又会怎么样? 但是如果你认为只有液体才能使你现身 那么你就错了 人体死亡的细胞, 土壤颗粒, 棉衣上的纤维 和其他的材料组成了灰尘 当我们出汗的时候,灰尘就会沾在我们皮肤上的潮湿的地方 当我们没出汗的时候,灰尘也会沾在我们的毛发上 因此,即使你做到了隐身 灰尘依旧会沾满全身 我们通常不会注意到我们身上的灰尘 因为在我们肤色映衬之下 我们看不见那薄薄的一层灰 但是,如果你能隐身 人们就会看见那一团人形的灰尘 走来走去,而且脚底特别脏 超级恶心! 如果你能隐身 你觉得你眼中的世界会变成什么样? 然而,答案是,什么都没有 你在黑暗中看不见东西的原因 是因为没有光 如果你看到了一个苹果 这是因为光照到了苹果上 又反射到了你的眼里 因此,你眼中的视网膜 为你的大脑捕捉了反射光线 并给你呈现出一个苹果像 如果你变得隐身 那么,依据科学,光线会穿过你 或者绕过你 而不是从你身上弹回去让别人看到你 但是这意味着你眼中的视网膜 也没有捕捉到光线 因此,你的脑中什么都没有 也就无法成像 如果没有一面镜子来停止光线 你能看见你自己么? 不,你不能 所以,当这个世界看不见你的时候 你自己也看不见这个世界 啊! 现在,你是否考虑过 隐身是不是永恒的呢? 如果是的话,当你受了伤 你该怎么从医生那里得到治疗? 医生不知道哪里应该上药 哪里应该贴创可贴 因为他们看不见你的伤口 而且,你自己也看不见 我是说,如果你生病了或者被感染了 在看不见颜色改变或者炎症的情况下 医生该如何对你进行诊断? 那么,如果所有人都永远的隐身了呢? 世界会变得多么无聊 如果街上一个人都没有 电视里也一个人也没有 电脑里也是 就像现在 隐身是非常孤独的 现在,你还想参加 哪一种研究超能力的物理课? 迅速改变身体的大小 还是获得超快速度 能够飞行 还是变得力大无穷 长生不老 还是 隐身