Chapter 133 "About this chapter contains a lot of popular science, so it is recommended to subscribe with caution"
When talking about scientists whose contributions in history are not worthy of their fame, one name may pop up in many people’s minds at the same time:
Tesla.
But actually.
Although Tesla is very capable, he is far from being as close to a god as he is rumored to be.
For example, "Einstein represents the upper limit of human beings, while Tesla is the lower limit of gods" is completely baseless.
Tesla today is actually highly attached to, mythologized and even demonized.
In layman's terms, it means being made a god.
The first time Tesla appeared in the public eye should be attributed to a documentary on the Science and Education Channel in 2009:
"Superman of Science: Nikola Tesla".
This documentary can be called the source of all evil later. It endorsed various rumors about Tesla in a serious tone, leaving many people with an inherent stereotype.
Then in 2015, the director, screenwriter and producer of this film all immigrated.
Now.
There are so many rumors that we can't even refute them.
This situation has far exceeded the level that can be described by the "IQ tax". Part-note, part of the description of Tesla can even be regarded as anti-intellectual.
Put it this way.
Today, more than half of the Baidu entries related to Tesla are rumors.
For example, it is rumored that in 1912 (or 1915 according to another), Tesla and Edison were awarded the Nobel Prize in Physics at the same time due to their contributions to electricity.
But both refused to accept the award.
The reason is that he cannot bear to share this honor with the other party.
Some marketing accounts used this rumor as a template, claiming that in the first thirty years since its creation, Tesla was selected to win the Nobel Prize in Physics nine times and twice with Edison.
And he gave up all the eleven Nobel Prizes to worthy people. Gods look down on the honors of mortals.
But in fact, let alone the eleven following times, even the first one is fictitious:
The 1912 Nobel Prize in Physics was awarded to Niels Gustav Dahlen, and the 1915 Nobel Prize in Physics was awarded to William Henry Bragg and William Lawrence Bragg.
Throughout Tesla's life.
He was only nominated for the Nobel Prize in Physics in 1937.
This was also the only time in his life that he was nominated and did not win, let alone refuse.
There are so many similar rumors that I can’t even count them.
It's completely false news fabricated out of thin air, or it just attributes other people's contributions to Tesla.
However, due to the problem of information barriers, this suture statement was believed by many people who did not know the truth, and it continues to this day.
Another reason why Tesla is deified is because of Edison, because this great inventor once did two very unethical things:
The first was to electrocute an elephant with alternating current, and then use the camera he invented to make a video and show it everywhere. This video can still be found online today.
The second specifically invented the electric chair driven by alternating current and persuaded the government to use the electric chair as a tool for execution.
The killing process of this thing is extremely cruel, that is, coils are tied all over the person's body, and then they are killed alive with electricity.
There are these two stains that cannot be washed away, so the reverse publicity effect on Tesla is very good.
Objectively speaking.
Tesla is not a top basic scientist, but he can be considered a top applied scientist or engineer.
The biggest difference between basic scientists and applied scientists is that basic science discovers the natural laws of the universe and is the most original discovery and research result.
It is also the basis of all inventions and creations, such as Mavericks, Einstein, and now Mr. Yang are such people.
Applied scientists or engineers turn basic scientific theories into practical technologies.
Their purpose is to invent and create new tools or improve production levels for use in social production and life.
all in all.
Tesla's status in the history of human physics cannot be ignored, and there is no need to belittle him as worthless. Winning one or two Nobel Prizes in modern times is definitely more than enough.
But he should never be made into a god. This is unfair to many sages who have truly made contributions, and is also harmful to the scientific research community.
And compared to Tesla.
There is a person who actually fits the definition of the three words "buried" better.
This person is
Cavendish.
Cavendish, this is a familiar but somewhat unfamiliar figure to everyone.
Many times.
The popularity of the character of the same name in the anime "One Piece" is much higher than that of this real-life character.
Most people's impression of him is that he measured the gravitational constant using a torsion scale, and even some unknown classmates have long forgotten about it.
But actually.
The hidden depth of this man of God is beyond anyone’s imagination.
Let me ask a question:
What would you do if you had the opportunity to discover Ohm's law, Coulomb's law and other achievements that could go down in history?
Presumably most people's choice is to publish them and enjoy this reputation until their death.
But Cavendish was different. What he did was.
Do you dare to believe that these theories rotted in manuscripts and were never published until death?
Tell the truth.
Even when Xu Yun himself learned about this when he was a Ph.D. student, he had a trace of doubt in his heart.
However, the background of the person who testified about this matter is really too big, so big that he can be called one of the top bosses in human history:
His name is Maxwell.
That is, the ultimate boss who wrote Maxwell's equations and laid the foundation for today's electromagnetic field theory. Without him, it can be said that there would be no mobile phones. At the same time, his personal ethics are also exemplary.
Late 19th century.
When Maxwell was invited to build the Cavendish Laboratory, he personally discovered 20 dusty bundles of mysterious manuscripts in the boxes left by Cavendish.
Of course.
In order to add a sense of mystery, some people in later generations described the box as a lockbox that required solving certain questions before it could be opened.
In the decades after Cavendish's death, only Maxwell could solve the mystery.
But unfortunately.
Maxwell's opening method is not that mysterious, he just uses some physical means:
Breaking the box lock with an axe.
These manuscripts are now in Room 6 of the Percival David Collection of the British Museum. The Louvre even had a dispute with the British Museum over this in the early years.
At that time, the Louvre believed that this was a manuscript discovered by Maxwell and therefore should be collected by the Louvre.
The British Museum said that you, a museum engaged in literature and art, can understand the physics manuscript of Trichosanthes edulis and rejected this request.
And according to manuscript records.
During the years 1772-1773.
Cavendish conducted an experiment called double-layered concentric spheres.
This experiment accurately measured the relationship between electric force and distance for the first time, and the index deviation did not exceed 0.02.
Later, the Frenchman Coulomb verified his discovery through experiments. From then on, the law of force between charges was called Coulomb's law.
Compared with Coulomb's torsion balance experiment, Cavendish's concentric sphere experiment was not only earlier, but also more accurate.
Although the measurement accuracy of later generations has reached the level of 10 to the power of 16, the experimental principles of Cavendish are still used.
If he had published this result, the Coulomb's law we see today might have to be renamed.
in addition.
Cavendish was also the first to propose the concept of electric potential and pointed out the proportional relationship between electric potential and current.
Since there was no instrument for measuring electric current at the time, Cavendish used his own body as an experimental instrument.
By estimating the strength of the current based on the numbness of the body, it was found that the potential (difference) at both ends of the conductor is proportional to the current passing through it.
This is Ohm’s law in the electrical chapter of our physics textbook.
At the same time, Cavendish and Faraday jointly advocated:
The capacitance of a capacitor varies with its dielectric, which is related to the substance inserted into the plate.
He also proposed the concept of dielectric constant accordingly.
And because he had done too many electrical experiments, he also proposed that there is "electricity" around every charged object, which is very close to the electric field theory.
Is it awesome enough?
It’s not over yet:
In an accidental experiment, Cavendish accidentally discovered a situation:
Some metals react with acids to produce a "flammable air."
This "combustible air" is hydrogen.
However, there was no general understanding of the gases produced by this reaction at that time. Robert Boyle collectively called all the gases produced "artificial air".
But Cavendish disagreed.
He insisted that this was a new substance.
So he used the most commonly used drainage gas collection method to collect some hydrogen.
After drying and purification, he successfully determined the density of hydrogen gas.
Of course.
The most important thing about this experiment was not to measure the density of hydrogen, but to discover that the two gases mixed together to form water.
This caused a lot of controversy at the time, because the chemical community generally believed that water is one of the elements that make up all things:
The "four elements theory" at that time, including water, earth, air, and fire, believed that water could no longer be decomposed.
Cavendish was even deprived of some of his titles because of this, and his annual income suddenly dropped to the equivalent of 50 to 60 million today.
Well, fifty or sixty million.
What a sad story - Cavendish was born in a big family. Because he chose the right team, he was basically no different from a chaebol, so Cavendish was able to do so many experiments.
What's even more unexpected is.
Cavendish also discovered that about 1/120 of the gases in the air hardly react, which are rare inert gases.
When were noble gases actually discovered?
The answer is more than a hundred years after Cavendish burped:
In 1895, Ramsay discovered argon gas using yttrium uranium ore and confirmed Cavendish's genius speculation.
In addition to the many contributions mentioned above.
Cavendish is most famous for his torsion scale experiment.
But it's more interesting to say.
On the contrary, Cavendish's most famous torsion scale experiment has been misunderstood by the world.
The torsion scale he used was actually designed by Michel, the previously mentioned Father Michel, and Cavendish was not the real inventor.
After Michel's death, the installation changed hands several times before being delivered to Cavendish.
Cavendish then made several detailed modifications to the device before he began the 25-year measurement process.
And it's worth mentioning.
What he measured with the torsion scale was not a gravitational constant.
He actually planned to measure the density and mass of the Earth for the popular astronomical research at the time, and at the same time verify the existence of gravity.
The operation of this experiment is not complicated:
First, illuminate the small mirror with light in a still state, and the light will be reflected to a far away place.
At this time, immediately mark the location where the light spot appears after the light is reflected.
Then there is a gravitational force between the objects, so just place two iron balls C and D with the same mass near the two iron balls A and B next to the torsion scale.
Then there will be a gravitational force F1 between A and C, and a gravitational force F2 between B and D.
The magnitudes of the two gravitational forces are different, somewhat similar to the tug-of-war of later generations.
Therefore, the torsion scale at this time will deflect slightly, and the far point of the reflection will move a larger distance.
Based on Cavendish's experimental records.
He calculated that the density of the earth is 5.481 times the density of water, which is 5.481 grams per cubic centimeter.
This is an error of only 0.65% compared to today's 21st century data.
As for the universal gravitational constant G, Cavendish did not actually calculate it. After all, the cognitive system at that time was still not completely sound.
But in his experimental records, the data for calculating G is quite complete, but it is just a conceptual understanding.
Even today's high school students can easily calculate the gravitational constant with considerable accuracy.
Therefore, in order to commemorate this great experimental physicist, later generations finally decided to award Cavendish the title of measuring the gravitational constant G.
In fact, with Cavendish's talent and knowledge, if he chose to publish the results, his reputation would definitely be much greater than it is now.
If you have to find a reason.
Probably because God spent so much time describing his wisdom that he could not paint a better character for him.
For example, although he is wealthy, he only wears a faded velvet coat and an outdated three-cornered hat all year round.
He is withdrawn and taciturn, almost afraid to talk to strangers and members of the opposite sex.
Even when communicating with the housekeeper he hired, he only passed notes and other methods to avoid embarrassment.
He is the largest depositor in London banks, but he has no interest in property.
For decades, investment advisors were asked to buy the same stocks until death.
The servant's parents had a fever, and he directly gave them the equivalent of 300,000 yuan in medical expenses.
And he complained more than once in letters to friends that he had too much money and didn't know how to spend it.
In fact, there are many big guys similar to Cavendish in history. For example, Gauss is also a very typical example.
After Gauss died, he left behind a pile of manuscripts that were not published. In the next 50 years, whoever could explain his manuscripts would be the best.
His gaze returned to its original position.
The core of the entire Cavendish torsion scale experiment can be put simply in two words:
enlarge.
Cavendish used a total of three amplifications in his experiments:
One is to change force into torque, which amplifies the force.
The second is to use the law in geometric optics that when a plane mirror rotates θ, the reflected light rotates twice θ to enlarge the angle.
The third is to use variable angular displacement as linear displacement, use a ruler to measure the displacement of the reflected light point, calculate the rotation angle, and amplify the macroscopic displacement.
These three amplifications are the innovation of this experiment.
True.
Judging from the tools that Xu Yun can currently find, there may be large errors in the twisting scale experiments in the Northern Song Dynasty.
But don't forget.
There is also a gap between his and Cavendish’s goals:
The Cavendish torsion scale experiment was first to verify universal gravity, and secondly to calculate the density and mass of the earth through data. The collected information could also deduce the gravitational constant.
At the moment, Xu Yun only needs to restore the phenomenon and prove that there is gravity between objects. He does not need to calculate specific values.
As for the slender light required for the experiment, it is not difficult:
When some later marketing accounts introduced the Cavendish experiment, they said that he used lasers, which seemed to have no problems.
But as long as you know something about the history of science and technology, you will know:
The principle of laser was only invented by Einstein in 1916.
Therefore, Cavendish's real operation was to first move the equipment to a dark room and fix its position.
Then use the inverse relationship between the divergence angle and the spot radius of w0X2θ0=w0'X2θ0'=2λ/π as the design basis, and you can simply make a glass lens.
A quarter of an hour later.
The entire equipment has been debugged.
Xu Yun asked Mr. Xie to stand outside the house, with an instrument similar to a selfie stick inserted into the ground beside him.
The lens is fixed on the top of the device, and the lens can be easily rotated.
After a few more minutes, Xu Yun said:
"The boss is in charge, it's time to start."
Mr. Xie nodded and had no objection to Xu Yun directing him:
"Understood."
Then he followed Xu Yun's previous instructions, slowly turned the lens, and began to correct the light.
Xu Yun's eyes stayed on the mirror, staring closely at the changes in the light.
After a while, he suddenly said:
"Stop! This is the location!"
Mr. Xie Duguan quickly stopped turning.
Then Xu Yun turned around and said to Xiao Zhao:
"Your Highness King Jian, please go to the wall and mark the location of the light spot with chalk."
Xiao Zhao obediently picked up the chalk and walked to the wall.
A white dot the size of a thumb was drawn on the reflected light spot:
"Master Wang, is this okay?"
Xu Yun nodded towards him, and then said to Lao Su:
"Master, it's our turn."
Lao Su rolled up his sleeves, picked up an iron ball from the table, and approached the small iron ball on the left side of the torsion scale.
Xu Yun picked up another iron ball and approached the big iron ball on the right.
As the iron ball got closer, certain changes invisible to the naked eye occurred.
Less than a moment.
Xiao Zhao by the wall suddenly shrank his pupils and said in surprise:
"Young Master, the light spot has moved!"
Old Su was stunned when he heard this, turned around and waved to Xiao Li beside him:
"Qingzhao, hold this ball for me."
After simply handing the ball over to Xiao Li, Lao Su quickly rushed to the wall and carefully inspected the light spot.
I only see this moment.
The light spot has disappeared from below the position marked by chalk and moved to.
The other side is about a foot long!
Lao Su's heart suddenly twitched hard.
Before the experiment began, he personally inspected the four iron balls.
He can guarantee that there is no magnetic attraction between the iron balls, and there is not even a little bit of wind in the room.
At the same time, during the experiment, Xu Yun and he did not come into contact with the twist.
So theoretically.
The entire torsion scale combination is always in a balanced and static state, and it is impossible to deform due to the approach of the iron ball.
That is to say
After some technical magnification, they actually witnessed the existence of objects
gravitational!
This concept has a much greater impact on Lao Su than the explanation of gravity - after all, Lao Su or many sages have long been curious about the situation in which objects fall, and have made conjectures.
Although the proposed speculation is somewhat different from gravity, the nature of this force is still similar.
It's just that there is no real special soil in the deepest core of the earth that attracts objects by magnetic force.
Therefore, although the interpretation of gravity conflicts with Lao Su's cognition, it does not lead to the collapse of the three views.
But what this current experiment proves is that there is a weak but real connection between any two objects on the ground - it may be a person and a person, it may be an object and an object, or it may be a person and an object. Attractive!
This is an idea that no one has mentioned since ancient times!
The concept of gravity is like in the future, you and your online dating partner showed up on Valentine's Day today, and you plan to show off your love in the circle of friends.
As a result, after meeting, you find that the other person is a p-picture monster. His appearance is completely different from the photo. His measurements are both 120cm, height 160cm and weight 160cm.
Although this kind of mental shock is a bit big, it won't drive you crazy in any way.
The concept of gravity is different.
It is no longer within the range of p-picture monsters. It is equivalent to finding out that your wife is a 6-meter-tall skeleton after you run away!
With such a series of mental shocks, most people would easily experience a collapse of their outlook on life, or even be frightened to death.
But on the other hand.
This is also a fact that is obvious to everyone. Even if you are really scared to death, you cannot change the nature of its existence.
Think of this.
Lao Su couldn't help but raise his head and looked at the light source outside the room.
At this moment.
This subtle light source is like a portal, slightly opening up a missing corner of the truth of the world.
That was an area that he had never thought of or touched in the past decades
Then he forced himself to calm down, ignored Xiao Li and Xiao Zhao who were also shocked, and turned to Xu Yun and asked:
"Xiao Wang, if my memory is correct, you seem to have said it before.
Are the earth under our feet and the stars in the world all round? ”
Xu Yun nodded and replied:
"That's right."
Hearing these words, Lao Su's eyes suddenly glowed with light.
There was even a hint of expectation in his tone:
"Since gravity can be proven by physical objects, Xiao Wang, do you have any evidence to support the statement that stars are round?"
Xu Yun was silent for a moment and still nodded:
"Yes."(End of Chapter)