Shulou(Shulou.com)11/24 Report--

Pearl milk tea must have been drunk by everyone. I wonder if you can finish all the pearls. Why is it easy to leave pearls? How can we eat them all? Q1. How does the liquid in the lighter turn into fire? by livy

A:

To put it simply, the piezoelectric ceramic produces an electric spark under pressure, which ignites the liquefied petroleum gas in the lighter to produce fire.

The disassembly of the lighter is shown in the following picture, which should be very familiar to everyone.

The picture is derived from the reference material when we press the hand of the lighter, the pressure is transmitted to the piezoelectric ceramic, normally, the piezoelectric ceramic has no electricity, under the action of external force, there will be charge accumulation at both ends, guided by the conductor. the tip discharge produces an electric spark. While pressing, with the participation of the internal lever, the nozzle opens. The fuel stored in the lighter is liquefied petroleum gas (LPG), usually butane. When it is not working, the internal pressure is relatively high. When the nozzle is opened, the liquid butane near the nozzle is instantly vaporized. Finally, the butane gas is ignited by an electric spark.

Reference materials:

[1] Zhu Leilei, Xiong Jufeng. Physical principle and teaching application of lighter [J]. Science and Technology Wind, 2022 No. 507 (31): 121-123.

By Frost White

Q2. Why are there always two mouths on the stick of a lollipop? By Anonymous

A:

In fact, there are quite a few lollipops with only one hole at the top. Of course, I guess the point of the question is not how many mouths there are.

Why should there be a hole at the top of the lollipop? we actually talked about it in issue 208 Q1, which is actually to jam the candy bar and prevent it from slipping when it is not tightly fixed with the plastic bar. After all, if the candy just rotates around the stick, it just doesn't taste good, but if the candy slips out along the stick, then the children who buy the candy may have an earth-shaking storm to cry.

The process of making lollipops is roughly like this: when the sugar is melted into syrup and cooled and semi-solidified in the mold, the sugar can not only be shaped, but also can flow slowly. use the machine to cooperate with the mold to shape the sugar into the desired shape-if it is ordinary, it can be formed into sugar balls, some flower work can be spread out into candy cakes, and the whole work can be turned into all kinds of small animals.

Insert a plastic rod after shaping

The semi-solidified sugar slowly flows into the hole.

After the source reference material solidified, the sugar and the stick were inseparable and ran on the assembly line together.

Reference materials for drawing sources:

Lollipop production

By is a Tibetan fanatic.

Q3. Why do chopping onions make your eyes hot and shed tears? By Shadow Wang Xi

A:

This is actually the self-protection mechanism of living things.

When onions are chopped, their plant tissue is also destroyed, and lacrimal factors are released inside the cells. Specifically, each cell inside the onion contains a vacuole filled with alliinase, which converts the amino acid sulfoxide in the onion cell into sulfonic acid, which is then quickly reacted by another enzyme called lacrimal factor synthase (LFS) to form cis (formula) propionylthionine S-oxide (syn-Propanethial-S-oxide). Because cis-propylthioaldehyde-S-oxide is a volatile liquid, it can be used as a tear gas and can easily spread into the air.

Propanthial-S-oxide | Image source network at the same time, the cornea has nerve endings that are very sensitive to tactile, temperature and chemical substances. When the nerve on the cornea detects the presence of cis-propionate-S-oxide, it sends a signal to the central nervous system and then stimulates the autonomic nerve fibers distributed in the lacrimal glands of the medial eyelid to produce tears. The purpose is to dilute this irritant to protect the body itself.

Cornea | Image Source Network finally, it is recommended that the next time you cut onions, you can freeze them in advance or soak them in cold water for a while, then wear swimming goggles and turn on the ventilation system to cut onions quickly in order to enjoy the perfect experience of chopping onions.

Reference:

Onion

Cornea

By 17

Q4. Why is it that the remaining pearls are not easily sucked up after drinking pearl milk tea? By, a nebulized animal.

A:

Because the pearl and milk tea is a pair, you finished the milk tea, only pearls, it is very lonely, do not want to come up.

It's a joke, but it's because there's no milk tea. Pearls are made of cassava powder. According to life experience, the density of these pearls is about the same as that of milk tea, because some pearls float on the milk tea and some sink at the bottom of the cup. The pearls we eat are actually sucked up along with milk tea. The diameter of the pearl must not be greater than or equal to the inner diameter of the straw. Such pearls will block the straw. But the diameter is less than the inner diameter of the straw means that the pearl can not isolate the upper and lower air in the straw, the straw is connected from top to bottom, there is no pressure difference, it is naturally impossible to suck it up. So pearls are all floated in milk tea and sucked up. Milk tea is a fluid that can isolate the air. When you inhale, the air above the liquid surface of the straw is sucked away, and the air pressure decreases. Under the action of atmospheric pressure, milk tea is sucked up, and the pearls inside are naturally brought up.

But if the milk tea is drunk too fast, the pearls that sink at the bottom of the cup will not come up without the help of milk tea.

Personally, I have several ideas to solve this problem:

First, stir the milk tea with a straw before the milk tea is finished, roll up the pearls lying flat at the bottom of the cup and take the opportunity to take it away.

The second is to put the straw on the pearl's head, suck it against it, and solve it one by one.

If there are diehards, consider poking it with the tip of a straw, putting the pearl on the straw, eating it, or directly smashing all the pearls, but these methods test the technique.

If it doesn't work, I have the ultimate trick: open the lid and drink it! This fat starch guy will definitely roll into your mouth!

By Frost White

Q5. Why is there the saying that "cephalosporin is on the wine, and a wave of it is sent away"? By 523

A:

Because it's really easy to get into trouble.

Drinking after taking cephalosporins is prone to "disulfiram-like reaction". Disulfiram is the generic name of abstinence drugs. even if you drink a small amount of alcohol after taking this drug, the body will produce serious discomfort and achieve the goal of abstinence from alcohol. "disulfiram-like reaction" refers to the symptoms of drinking after exposure to disulfide. After taking some drugs, it will affect the metabolism of alcohol and lead to the accumulation of acetaldehyde in the body, resulting in a "disulfiram-like reaction".

High school biology tells us that the metabolism of alcohol in the human body is divided into two steps: the first step is to open the refrigerator door. I'm sorry I crossed the stage. The first step is to oxidize the hydroxyl group of alcohol into aldehyde group under the action of ethanol dehydrogenase, and ethanol becomes acetaldehyde, which is toxic to the human body. The common reaction is that the heart beats faster and the blood circulation becomes faster, so acetaldehyde should continue to be metabolized as soon as possible. The metabolism of acetaldehyde is the second step in the digestion of alcohol by the human body. another enzyme, acetaldehyde dehydrogenase, is needed. Under the action of acetaldehyde dehydrogenase, the aldehyde group is further oxidized into carboxyl groups, and the metabolite is acetic acid, which is eventually metabolized into carbon dioxide and water. Some people blush easily because of the lack of acetaldehyde dehydrogenase. Such people usually drink poorly, because acetaldehyde cannot be metabolized quickly in his body. After acetaldehyde accumulates, he blushes.

Some drugs can inhibit acetaldehyde dehydrogenase, which will also lead to the accumulation of acetaldehyde in the human body, resulting in a "disulfiram-like reaction". The main symptoms are facial flushing, conjunctival congestion, blurred vision, violent pulsation of blood vessels in the head and neck, dizziness, nausea, vomiting, dry mouth, chest pain, breathing difficulties, and in severe cases, acute heart failure, acute myocardial infarction, acute liver injury, and even convulsions and death. Therefore, please pay attention to it.

In addition to cephalosporin, some nitroimidazoles and hypoglycemic drugs may also cause a "disulfiram-like reaction." you must follow the doctor's advice when taking medicine.

Drinking is harmful to health, minors are not allowed to drink alcohol. Reference:

Emergency Story: the terrible "double Sulphur"

By Frost White

Q6. Why is the scope higher than the barrel and the bullet can be hit accurately in the center of the gun? By Anonymous

A:

As long as it's not parallel to the barrel of the gun.

It seems that this picture can solve this problem. The blue one is the gun, the red one is the trajectory, which is affected by gravity, it is a flat throwing line, and the black one is the sight line of the sight. In fact, the sight line of sight is not parallel to the barrel of the gun, but a sharp angle with the barrel, so that the line of sight and the trajectory will eventually meet at one point, and that is the target.

Of course, the line of sight and trajectory can only determine one point, so the distance between the intersection and the muzzle is certain, that is to say, the angle between the line of sight and the barrel corresponds to the distance of the target. We can't control the distance of the target, but we can adjust the line of sight. Therefore, when shooting, first determine the distance of the target, and then adjust the scope according to this distance, in order to achieve a hundred shots.

Turning a blind eye is not necessarily to let you go, but may also be aimed at you. | the picture comes from the Internet. Take our political commissar Zhao as an example, the political commissar uses a 38 cover, and there is a mechanical door that can be flipped, and there are different distance marks on the door. When in use, the position of the gap door is adjusted according to the distance. The farther the distance is, the higher the door is. The greater the angle between the line of sight and the barrel of the gun, to ensure that the target can be killed eventually.

The effective range of the camera door of the 38 covers is 460m, but the ruler is 2400 meters. The picture comes from the network. Here we should also notice that the height of the camera door is obviously higher than the gap of the gun muzzle. This also proves that there is indeed a sharp angle between the actual line of sight and the barrel of the gun.

By Frost White

Q7. Why are stars spherical in the universe? By jjyu

A:

There are probably two reasons.

One is gravity. For the planet, gravity is absolutely the core role. We can do a simple calculation. Take hydrogen molecules as an example. The H bond energy of HMel is 436kJ / mol, which means that if we want to decompose 1mol hydrogen into hydrogen molecules, we need 436kJ energy. The average to each atom is, where is the Avogadro constant. And if it is a hydrogen atom on the surface of the earth, the gravitational potential energy is about:

Where M is the earth mass and m is the molecular mass of hydrogen.

It can be seen that on Earth, the gravitational potential energy is already in the same order of magnitude as the bond energy of hydrogen molecules. If there is a planet of the same size and four times the mass of Earth, then hydrogen molecules cannot exist on the surface of such planets. Gravity will tear up hydrogen molecules. But in fact, for many planets, the binding energy between its components is less than the Hmurh bond energy, or take the Earth as an example, the surface is rock, we look at silicate, the binding energy between silicate molecules is relatively small, therefore, under the action of gravity, the mountain can not be infinitely high, although gravity can not destroy silicate molecules, but it can easily tear up rocks.

There are also many very dense planets in the universe, such as neutron stars or white dwarfs. On neutron stars, the gravity is so strong that they can tear atoms apart. Therefore, under the isotropic gravity, the planets are very round.

Another important factor is rotation. When a celestial body rotates, the angular velocity is the same. The more prominent the part, the larger the radius, which means that the greater the linear velocity, the greater the centripetal force, otherwise it will be thrown out. Therefore, the protruding part of the celestial body tends to leave the celestial body, and if there is too much protruding on one surface of the celestial body that gravity is not enough to provide centripetal force, the "protruding molecule" will break away from the celestial body in the process of rotation, and the rest will naturally be more rounded. However, the existence of the rotation axis actually tends to cause celestial bodies to form ellipsoids rather than positive spheres.

By Frost White

Q8. What is the difference between high-dimensional space in mathematical sense and high-dimensional space in physical sense? By zinero114514

A:

The dividing line between mathematics and physics is not so clear. My personal point of view is that the space in the mathematical sense is a series of parameters, but in the physical sense, each parameter of the high-dimensional space has a dimension of length, which constitutes a real space, which is a special mathematical high-dimensional space.

First, let's take an example of a high-dimensional space in mathematics. For example, a person's scores in language, mathematics and English constitute a six-dimensional space. For A whose coordinates in the score space are (120, 150, 150, 140, 100, 100, 90), he will probably like to see our official account. As for B, whose coordinates are in (90,100,130,130,20,70,70), he probably won't like to look at our official account. If we want to describe this preference quantitatively, we can locate our official account on the plane of the space (xmem140djjjn090pj80), and then calculate the straight line distance, An is away from us, and B is away from us.

In addition to the results, a parameter space can also be constructed with physical quantities. for example, the phase diagram of a simple pendulum is a two-dimensional parameter space composed of swing angle and angular velocity.

Phase diagram of a simple pendulum, the horizontal axis is the angle and the longitudinal axis is the angular velocity. Source: 3Blue1Brown this is a simple pendulum that only swings on the plane. If it is an object moving in three-dimensional space, its three position components and velocity components can form a six-dimensional parameter space. But this is still a mathematical high-dimensional space. To really bring out the concept of physical high-dimensional space alone, we should start from the 25-dimensional real space put forward by string theory.

In string theory, the world is made up of vibrating strings, and different vibrating strings produce different particles, just as different vibrating strings produce different notes.

Open and closed strings in string theory | Source: the vibration of CERN Courier strings in each real space dimension contributes to the mass of photons, while relativity requires that the static mass of photons must be zero, so (see Section DE in [2])

The solution of Demp25 represents 25-dimensional space. The first term 1 in the above equation comes from the energy excited by the string, and the second term represents the zero point energy, which is generated by the quantum uncertainty principle, which means that the string cannot rest with certainty, and it will vibrate even in the lowest energy state. In the second term, the first number-1Comp12 comes from the summation of different vibration frequencies. You may be surprised why a negative number is summed up, but it is valid in the sense of mathematical analytic extension. The second number 1Universe 2 is because the zero point energy is half of the unit energy quantum, which is a conclusion of quantum mechanics. The-1 in the third number (Dmur1) is because the photon does not vibrate in the direction of propagation, but only in the remaining Dmuri one-dimensional space.

String theory makes physicists realize for the first time that it is necessary to introduce high-dimensional space to make a theoretical system logically consistent. After that, string theory is upgraded to superstring theory by introducing the idea of supersymmetry. Strings vibrate not only in ordinary space, but also in hyperspace, so using similar self-consistent conditions, physicists work out the 9-dimensional Durge space.

Later, it was found that superstring theory could be divided into five different forms. In order to unify them, Edward Witten proposed to regard the five superstring theories as a projection of a higher-dimensional theory. This wonderful idea is called M theory.

So why can we only perceive three-dimensional space? At present, it is believed that the rest of the dimensions are curled up into the compact micro-world. However, whether the theories of these high-dimensional spaces are correct or not remains to be further studied.

Reference:

Finally know why the universe is 11-dimensional, 11 unexpectedly came from …...

A brief introduction to string Theory

That's right. The sum of all the natural numbers is-1 prime 12.

By sheep herding

This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: Frions

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