I recently watched Matt Damon's not-so-new new film "Shrunk Down." The background of the story is that in order to save all human beings once again, the omnipotent Westerners have invented a technology that can shrink the cells of organic life as a whole, which can be done through a very simple process (similar to baking bread, first shave all the body hair of the target , remove all foreign objects such as dentures, brackets, steel nails, etc., and then inject a drug into the human body, and then send the person into the microwave oven—you read that right, it’s really a microwave oven—bake it), you can put a one-meter-eighth The big man was reduced to a 12-centimeter little man. Except for the shrinking of the body, all other physiological functions are normal, which can greatly reduce the material and energy consumption required by a person's daily life, and can save the earth from the crisis of resource shortage and climate warming. I have to complain here. Although Americans have saved the earth thousands of times in the movie, their math is really poor - the movie says that new technology can reduce the size of human cells to 20 times One, then a person who is 1.8 meters should not become 12 cm, but should be 9 cm.
The purpose of this article is not to make any comments on the plot of the film, but to interpret the setting of the film based on what I know about physics and biology: shrinking the human body to 12 cm, what will it bring? problems, so that the "miniature people" who get a new life will encounter new problems in their new life. Let's talk one by one.
1. Weight and Stress Issues
Since the cells are shrunk as a whole, that is to say, although the size of the human body has become smaller, the weight has not changed at all (well, movies are movies after all, you can compress the cell structure, but you can’t compress water molecules, each one meter Eight adults have at least 40kg of water in their bodies, which means you can't compress a person below 40 liters in volume anyway. We'll just have to ignore that). A person who is 12 cm tall and only 1.5 cm long on the soles of his feet and weighs 75 kg, this creates a serious problem - a simple math problem: __bk:abkok The area is proportional to the square of the length, and the volume is proportional to the cube of the length. proportional. The 180 cm human body is reduced to 12 cm, the length is reduced to one-fifteenth of the original, the cross-sectional area of the bones and the area of the soles of the feet (in the movie, the body proportion of the little man is the same as that of a normal person) will be reduced to 225 of the original. One, the volume becomes 1/3375. The consequence is that the bones have to bear 225 times the load of a normal person—equivalent to a normal person carrying 17 tons of things to run around—this is an impossible task for human and animal bones. Then we assume that the overall reduction of cells greatly enhances the strength of bones, stronger than steel, stronger than carbon fiber, stronger than carbon nanotubes, and it is not a problem to withstand more than 200 times the load, then there is another problem that cannot be ignored, that is The density of this little man is 3375 times that of ordinary people. Osmium, the densest element on earth, is only 21 times the density of human body (osmium 22.5 grams/cubic centimeter, human body 1.06 grams/cubic centimeter). We did not create a shrinking human being. , but accidentally created ultra-dense matter that is not found on Earth. Imagine if a person with a height of 180 cm weighs more than 240 tons (75 kg X 3300 times), his bones are extremely strong and can hold up, but... his feet are muscles! What kind of flesh and blood can withstand the pressure of more than 200 tons - from the pressure on the soles of the feet, a height of 12 cm and a weight of 75 kg is equivalent to a height of 180 cm and a weight of 240 tons. If the director argues that I don’t care, I just want their body density to be the same as ordinary people, well, then the 12 cm tall little person should be 1/3375 of the weight of 75 kg (not 15/15). One, why?), that is, 22 grams, which can be blown away by a gust of wind. In this way, it is difficult to maintain the same way of movement as a normal person by reducing the overall height of the person to 12 cm. It seems that the screenwriter has to go back and sort out his thoughts and make it more reasonable.
Second, you have to use a "washbasin" to drink water, and the classic wine bottle design needs to be changed
This is a screenshot of the film. The miniature man is holding a wine glass of normal proportions and sipping red wine. In view of the size of miniatures, there are many inconveniences in real social life, the screenwriter designed a miniature community for them, where there are reduced buildings, reduced vehicles, reduced trees, flowers, and reduced pets. The community also carefully covered it with a huge wire mesh "mosquito net" to avoid the threat of mosquitoes and other insects (for the miniature people, it is a mosquito the size of an eagle and a dung beetle the size of a wolf). But the director, you also reduced the glass and bottle to 1/15, which is not right. How to say, the surface tension of water is very strong, recall the shape of the dew drop we see, the diameter of the bottle mouth is reduced to less than 2 mm by the ratio of 1:15, and the champagne cannot be poured out anyway - Think of our experience with toilet water or balm. Even a wine glass about 6mm in diameter (which actually only holds one "drop" of wine) can be difficult to pour. Because of the surface tension of water, in order to drink water smoothly, our miniatures cannot use cups, they have to use a "washbasin", or at least a "sea bowl". If it doesn't apply at all, they have to use wine barrels, and they have to be open-mouthed. It's okay to pack red wine and whiskey, but I'm afraid they have to think of other ways to pack champagne. Considering that their weight is likely to be 22 grams in the previous section, I think of a benefit of the surface tension of water - when soaking in the bathtub, the miniatures can easily float on the water with the help of the surface tension of water, especially It's when they haven't bathed for a long time, and they're dirty and muddy. This picture is still very exciting to think about.
3. Metabolism and Lifespan Issues
The premise of the film, the miniature human technology is to greatly reduce the material and energy consumption required to maintain life without affecting the quality of life. This idea is very good, but the reality is very cruel, I am afraid that the director can't think of it. Going back to the simple mathematical problem mentioned in the first section, the "specific surface area" of a miniature person (the surface area of an object divided by the mass, here is the approximate calculation method of dividing the surface area by the volume) is 15 times that of a normal person. What does this mean? In order to maintain body temperature, the heat production rate of microscopic people must be maintained at a level ten times faster than that of normal people. The situation in the biological world also shows this. The smaller the body temperature of the warm-blooded animal, the higher the breathing and heartbeat frequency, and the faster the basal metabolic rate. Of course, even if the basal metabolism is ten times faster, but the body weight is only 22 grams, isn't it, the substances consumed are still far lower than normal people, the screenwriter said nothing wrong. There's nothing wrong with it, the problem is elsewhere: the faster the cell's metabolism, the shorter the cell's lifespan. Elephants have a heartbeat of 20 times a minute and can live for decades, while mice have hundreds of heartbeats per minute and can live for two to three years. This problem is serious. Poor Matt Damon reduced his body in order to obtain a refined life, but he did not expect to shorten his life by the way. This is not worth the loss. However, he can go to a lawsuit and apply for compensation. Because of the negligence or intention of the Microman Company, there will be such side effects without prior notice. I dare to guarantee that Brother Duomo will win the lawsuit.
Fourth, want to talk to an old friend who still maintains a "normal size"? I'm afraid you can only type
In the film, there are several scenes where "miniature people" communicate face-to-face with normal people. The editor and director obviously considered that the miniature people may have very small voices, so they are equipped with microphones and amplifiers every time. But wait, are you sure this will allow the miniatures to talk to normal people? I don't think so. We make sounds through the vibration of the vocal cords and hear through the vibration of the tympanic membrane, both of which use the vibration of the membrane. Membrane vibration is a very complex acoustic and physical process, and this paper only gives the simplest explanation. Each membrane has its own fixed spectral range, and can only "sound" or "hear" within this range. The size, shape, material, and tension of the membrane will change its frequency spectrum. Qualitatively speaking, under the same other conditions, the smaller and thinner the film, the more high frequency it is, and the larger and thicker the film is, the more low frequency it is. Elephants are big, and their vocal cords and tympanic membranes are large and thick, so elephants can communicate with infrasound waves; mouse vocal cords and tympanic membranes are small and thin, and rat voices are very high-pitched, and humans can't hear the ultrasound emitted by ultrasonic mouse repellers. , is a screeching noise to mice. In addition, the degree of tension of the membrane will also affect the spectral range, that is, the tighter it is, the higher the frequency is, and the looser it is, the lower the frequency is. That's what we mean when we sing high notes and squeeze our throats hard. Now what I'm about to say is clear - the frequency spectrum of the vocal cords and tympanic membrane of a miniature human being will shift to high frequencies, considering that the area of the vocal cords and tympanic membrane of a miniature human being is 1/225th the area and 15/15th the thickness of a normal human being One, the spectral range of their speech and hearing will undoubtedly shift to the high frequency end, most likely in the ultrasound segment (the frequency spectrum of normal human speech is about 50-700 Hz (fundamental frequency, not counting harmonics) , women are higher than men, children are higher than adults; the hearing range is 20-20,000 Hz. According to anthropocentrism, this frequency band is called the acoustic band, the sound waves lower than 20 Hz are called infrasound waves, and the sound waves higher than 20,000 Hz are called ultrasonic waves) , I can't figure out how much, but in general it's not wrong. In general, the voices of the miniature people are mostly ultrasonic waves to normal people, and the voices of normal people are mostly infrasound waves to the miniature people, and they cannot hear or even hear each other. It is almost impossible for the speaker to communicate smoothly (the amplifier can only increase the loudness by enhancing the amplitude of the sound, and cannot change the frequency), unless a two-way reversible "voice changer" is used to reduce the frequency of the miniature human's speech, Also upscaling normal people's voices, otherwise I'm sure it's easier for them to communicate by typing.
Shrinking bodies, shortened lives, increased risks, huge difficulties, Matt, are you ready?
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