Chapter 297 Roentgen: You are amazing and noble! (7.4K)
In the laboratory.
After discovering this abnormal light.
Faraday, Gauss, and Weber did not dare to neglect, and immediately gathered at the edge of the table.
I saw the heads of the three people touching each other, their eyes fixed on the vacuum tube in front of them.
Do not know why.
This picture reminded Xu Yun of an emoticon he had seen before he traveled through time:
Three golden retrievers gathered around a mat, looking at a small milk cat about the same size as their noses in the mat, with the words "Is this guy new here?" written next to it...
Ahem... This shouldn't be considered as bullying one's master and destroying one's ancestors.
after awhile.
Weber stroked his thick beard and turned to look at Xiaomai, with doubt in his eyes:
"It's really strange..."
"Classmate Maxwell, how did you discover this light?"
At this time, Xiaomai was still standing next to the switch. Hearing this, he pointed to the window and replied:
"I just flashed... ahem, the position I was standing just now was exactly facing that window."
"The window is in the corner, and the door is blocked by curtains, so the view in that area is relatively dark."
"As a result, when I turned my head, I suddenly felt something flashing on the vase, but when I turned my head, it disappeared again, so..."
Faraday raised his head and glanced at him, then said:
"That's why you thought this might be an illusion. Instead of telling us directly about this phenomenon, you chose to verify it yourself, right?"
Wheat nodded slightly.
be honest.
The flash of light just appeared for a short time and disappeared before he could take a closer look, so he really thought it was his hallucination.
Moreover, although the curtains on the windows had been drawn at this time, it was still broad daylight outside, and more or less sunlight would filter in.
Are you sure that the light shining on the vase is the light from outside?
So out of this mentality.
Wheat was not in a hurry to tell Faraday and Gauss about this situation. Instead, he rearranged the vases and conducted the experiment again.
The cause and effect of the whole thing is indeed nothing special, but the problem is...
What is going on with this light?
How did it appear?
What are its physical properties?
Now that electromagnetic waves have been discovered, Faraday and others are qualified to conduct more in-depth analysis of some phenomena.
Then Faraday thought for a moment, turned around, and said to Kirchhoff:
"Gustave, take out another Xiao Yan tube."
"Remember to cut the middle area into two sections, make them ten centimeters hollow from each other, and do the experiment again."
Kirchhoff was taken aback for a moment and confirmed to Faraday:
"Professor Faraday, you mean...cut a Xiao Yan tube into two pieces? The mouth to mouth is separated by ten centimeters?"
Faraday nodded:
"That's right."
Kirchhoff saw a trace of hesitation on his face and said hesitantly:
"Professor Faraday, there is no problem in intercepting the vacuum tube, but in this case, the degree of vacuum we have worked so hard to prepare will be affected..."
Mentioned it a long time ago.
The Xiao Yan tube...or the modified version of the Geissler tube is somewhat similar to the Crooks tube in structure.
In order to facilitate experimental observation, this vacuum tube can be twisted into two sections from the middle and then increased in length.
For example, the vacuum tube used in Leonard's experiment was once extended to 1.3 meters in length.
So it is not surprising that the vacuum tube is twisted into two sections separately, in order to add another part of the tube body for easier observation.
But as Faraday said, the method of not increasing the length of the tube after unscrewing it, but directly facing each other ten centimeters apart, is undoubtedly a bit puzzling.
yawenku.
Because the design purpose of the vacuum tube is to create a vacuum environment, once the two tube sections are exposed to the air, the vacuum degree will inevitably decrease seriously.
As soon as the vacuum degree drops, cathode rays become less likely to appear.
Facing Kirchhoff's question, Faraday waved his hand towards him and said:
"Gustave, you should do this first, I know what to do."
Seeing that Faraday insisted on this approach, Kirchhoff was puzzled, but he had no choice but to do it:
"Understood, Professor Faraday."
There were more than twenty "Xiao Yan Tubes" prepared by Faraday at the University of Cambridge this time, so Kirchhoff quickly prepared the brand-new equipment Faraday needed:
A vacuum tube is divided into two parts, ten centimeters apart from each other.
They are still connected to the circuit with wires on the outside to ensure that the cathode and anode can be connected without short circuit.
At the same time, Faraday placed a thermocouple at the cut end of the anode to observe the data.
After everything is ready.
Faraday turned on the power again.
A few seconds passed.
A blue-white light appears routinely at the cathode, accompanied by two or three dark areas.
But as the light path progresses.
When the light leaves the cathode cutout and comes into contact with the air...
The blue-white light only advanced three to five centimeters before completely dissipating in the air.
at the same time.
Faraday glanced at the thermocouple, which clearly displayed the temperature rise value:
0.00007.
This is a fairly small number.
According to a simple calculation based on the temperature rise conversion formula, it can be said that very few cathode rays reach the anode end.
This is true at the cut-off point, let alone the end of the anode.
See this situation.
Faraday turned off the switch and looked at each other with Gauss and Weber.
The three of them all saw a sense of solemnity and excitement in each other's eyes.
This control experiment clearly illustrates one thing, whether it is the phenomenon or the digital feedback of the thermocouple:
The penetrating power of cathode rays in the air is weaker than they expected, and it can travel only a few centimeters.
But the light shining on the vase penetrated two meters of air!
This means that the energy levels, wavelengths, and frequencies of the two are different!
Think of this.
Gauss suddenly realized something and took out a cylindrical magnifying glass from his body - the kind commonly used by watch repair masters in later generations. He walked single-step to the vacuum tube that emitted the mysterious ray.
I saw him leaning down and moving his eyes wearing a magnifying glass to the vicinity of the anode.
A few seconds passed.
Gauss suddenly let out a cry and waved to Faraday and Weber:
"Michael, Edward, come and see!"
Faraday and Weber walked quickly to him one after another. Faraday put his hand on Gauss's shoulder and asked:
"What happened, Friedrich?"
Gauss took off the magnifying glass, handed it to the two of them, pointed at the end of the anode and said:
"Take a look for yourselves and pay attention to the position of the two rays of light."
Faraday and Weber looked at each other, and Faraday took the magnifying glass from Gauss first.
After adjusting the coefficients.
He also put on a magnifying glass and bent down to observe.
soon.
Faraday's thick sword eyebrows raised slightly, as if he had discovered something strange, and he leaned forward a little again.
About half a minute passed.
Faraday took a deep breath, stood up, and gave up the magnifying glass and his position to Weber.
Weber followed and reproduced his movements.
After Weber also got up.
Gauss asked him and Faraday:
"How about it, Michael, Edward, did you see it?"
Faraday nodded slightly, glanced at Riemann and Kirchhoff who were confused, and said slowly:
"As you can see, the entrance point of the cathode rays on the anode and the exit point of the unknown ray...are not on a horizontal line."
"You know, the anode is a metal plate."
In the field of optics.
If light undergoes some refraction phenomena in the medium, its incident point and exit point may indeed not be on the same horizontal line.
But this can happen on crystals, inside stones, or even in water or air.
But it is only impossible to happen in metal plates - because most metal plates of normal thickness cannot allow light to pass through.
This is the popular expression of ‘metallic opacity’.
The reason for this phenomenon can be explained by classical mechanics.
That is to say, metal has high conductivity and inherently high reflectivity, so the transmitted light will be dissipated by Joule heat.
Of course.
This explanation is relatively simple. The fundamental reason still needs quantum mechanics to explain, and it involves the issue of electron energy levels in metals.
As we all know.
The essence of light of various colors is electromagnetic waves of various wavelengths.
According to quantum mechanics, electrons in matter can be at various continuous or separated energies, called energy levels.
If an electron at a low energy level encounters a photon with a suitable energy, it will absorb the energy of the photon and jump to a higher energy level - suitable energy means that the energy of the photon is equal to the difference between the high and low energy levels.
Whether light in a certain wavelength band will be absorbed depends on whether there are such electrons and two energy levels.
If it is not absorbed, the light passes through the material.
This is transparency.
For example.
If the energy level of a substance is less than or equal to 0 and greater than or equal to 5, all electrons just fill those energy levels less than or equal to 0.
Then the energy of the photon must reach at least 5 before it can be absorbed, and the light with less than 5 will pass through.
Metals are opaque because the electron energy levels in metals are continuous over a wide range, and photons of any energy can be absorbed when they come in.
Useless knowledge has increased.JPG.
The topic returns to its original place.
So for metal anodes.
It is theoretically impossible for a beam of light to pass through from the left and then appear from a lower area on the right.
Either it is completely blocked, or it passes through some gap - but if this is the case, then the entry point and the exit point must be at the same position.
In other words.
The source of this abnormal light is not the cathode nor the ionized air in the tube, but...
The anode itself!
Think of this.
Gauss's heart skipped a beat, turned to look at Faraday, and asked:
"Michael, what kind of metal is the anode?"
Faraday was stunned for a moment, then subconsciously blurted out:
"Tungsten plate!"
Immediately, he suddenly thought of something and turned his head sharply to look at Xu Yun.
But what surprised him was...
Xu Yun's expression at this time was also mixed with confusion, shock and confusion.
Judging from Faraday's experience...
This really doesn't look fake.
Then he and Gauss looked at each other, pondered for a moment, and then asked Xu Yun:
"Classmate Luo Feng, has Mr. Feiyu ever said why he chose tungsten plates as the anode?"
Only then did Xu Yun come back to his senses, and once again shook his head with a cute look on his face:
"I can't come."
Faraday stared at him seriously for a few seconds, feeling a little doubtful in his heart.
Could it be that he really didn’t know about this?
After all, tungsten plates are also considered common electrodes. In some cases, they are even easier to obtain than zinc plates. They are not uncommon in laboratories.
A tungsten plate with a diameter of one centimeter has no cost.
In addition, the place where "Fat Fish" lives is the Netherlands, which is rich in tungsten plates...
In this way, coincidence can also explain the past...
Think of this.
Although Faraday was still hesitant, he still slowly withdrew his gaze.
Looking at Faraday who returned his attention to the vacuum tube, Xu Yun couldn't help but let out a sigh of relief.
Fortunately, okay, I finally got over it this time.
Although from a theoretical point of view, both copper plates and zinc plates can excite this special ray.
However, the excitation conditions of these materials are relatively complex and require at least a high-voltage generator.
Although a high-voltage generator is not difficult to find, it is not easy to properly incorporate it into the research process of cathode rays.
Once Faraday and others discovered that cathode rays could be generated without a high-voltage generator, it would be easy to blame themselves for the cause of the mysterious rays.
This is obviously not a good thing.
Actually.
Xu Yun indeed had no intention of leading Faraday and others to discover new rays this time. His intended goal was actually to reach cathode rays.
Unexpectedly, he tried so hard to push history forward a small step, but Xiaomai, a fool... or the son of luck, stupidly kicked history forward...
That's right.
The son of luck.
Why do you say that?
the reason is simple.
The light discovered by Wheat is none other than the famous...
X-rays!
Historically, the discoverer of X-rays was Wilhelm Conrad Roentgen, and his discovery of X-rays was recorded in elementary school (or I forgot about it in middle school) textbooks.
It was on the evening of November 8, 1895, that Roentgen began to study cathode rays as a routine.
At that time, in order to prevent the influence of external light on the discharge tube and to prevent the visible light inside the tube from leaking out of the tube, he darkened the entire room and made an envelope for the discharge tube with black cardboard.
In order to check whether the envelope leaked light, he connected the discharge tube to the power supply. He was satisfied to see that there was no light leakage from the envelope.
But when he cut off the power, he unexpectedly discovered a flash of light on a small workbench one meter away. The flash was emitted from a fluorescent screen.
However, cathode rays can only travel a few centimeters in the air, a conclusion that has long been confirmed by others and his own experiments.
Therefore Roentgen made a judgment:
This is not a cathode ray, but a new type of ray.
Later, after repeated experiments, Roentgen finally determined that this was a new type of ray that was not yet known, and gave it a name:
X-ray.
Later, a classic appeared:
One day when his wife came to the laboratory to see him, he asked her to put her hand on a photographic film wrapped tightly in black paper, and then pointed and irradiated it with X-rays for 15 minutes.
After development.
The film clearly shows the bones of his wife's hand, as well as the wedding ring on her finger.
Many people are deeply impressed by Mrs. Röntgen's photo of hand bones after many years.
Later, Röntgen won the Nobel Prize for this and became the winner of the first Nobel Prize in Physics.
But on the one hand.
Due to the age of the audience, the textbook does not describe in depth the process of Roentgen's discovery of X-rays.
In the original history, Roentgen's discovery of X-rays was actually far from being as simple as what was written in the book.
Students who have studied optics should all know this.
Light is actually the transfer of energy, and its essence is a flow of photons in a specific frequency band.
The light source emits light because the electrons in the light source gain additional energy and release energy in the form of waves during the transition process.
This is true for sunlight, electric light, and firelight.
Therefore.
In essence, light is a kind of electromagnetic wave, which relies on energy information transmitted by photons.
If there is energy, then naturally there is frequency.
During the long-term evolution, the human eye is only sensitive to light in the frequency band of about 380 to 780nm, so the electromagnetic waves in this specific frequency band are called visible light.
That is, red, orange, yellow, green, blue, purple, etc.
In addition to visible light, there is also a lot of light that is invisible to the human eye.
For example, radio waves, infrared rays, ultraviolet rays, X-rays, and gamma rays are invisible lights.
These lights are all within a certain band and frequency of the electromagnetic spectrum.
X-rays are electromagnetic waves second only to gamma rays, with wavelengths between 10 nanometers and 0.01 nanometers, frequencies between 3^16 and 3^20 Hz, and energies between 124eV and 1.24MeV.
This is the energy of each photon. X-rays are high-energy rays, so they have strong penetrating power.
When X-rays irradiate the human body.
Some of the x-rays are absorbed by the body's materials, while most of them pass through the atomic gaps.
The higher the frequency and the shorter the wavelength of X-rays, the greater the energy and the stronger the penetrating ability.
In the process of penetrating objects.
Depending on the density and thickness of the object, the absorption of X-rays varies.
Therefore, the X-rays that pass through are either strong or weak, so that the structure of the object being passed through is displayed on the photosensitive film - this is the principle of X-rays in later generations.
Having said that, the question arises:
Since X-rays are invisible light, how did Roentgen notice them?
The textbook only states that Röntgen discovered light spots on the screen outside the vacuum tube, but X-rays are not visible, so theoretically they cannot be noticed.
Of course.
Seeing this, someone may ask:
That's not right.
Why can't ultraviolet light be seen, but ultraviolet light can see purple light?
the reason is simple:
Because the manufacturer of the ultraviolet lamp adds a photoinitiator or photosensitizer into the lamp, active free radicals or ionic radicals are generated after absorbing ultraviolet light, thereby initiating polymerization, cross-linking and grafting reactions.
This process has its own term, called UV curing.
The physical properties of UV light radiation are similar to visible light, so you can see the 'light' of the UV lamp.
You can't see real ultraviolet light.
So for Roentgen.
Even in a closed room, at most a little light will appear at the anode due to the ionization effect (that is, the emission point observed by Faraday and others), but it should not be visible at the end.
What really helped Roentgen discover X-rays was actually a substance called barium cyanide platinate.
When it comes into contact with X-rays, it emits a visible fluorescence.
Barium cyanide platinate is a common paint in the 19th century, which is common in laboratories and literary and artistic creations.
At that time, Roentgen saw that the object that projected the X-ray spot was a screen coated with barium cyanide platinum oxide.
And now in this laboratory.
The only one coated with barium cyanide platinum oxide is...
The exterior decoration of the vase that Wheat saw.
So sometimes Xu Yun really has to wonder whether there really is such a thing as a son of luck in the world.
in his plan.
The reason why a tungsten plate is used as an anode during the experiment is just to fix it into a commonly used material for cathode ray research.
Just like the commonly used copper rods in electrolytic cells, let future generations develop a habit.
Once more people use it, it can take as short as three to five years and as long as eleven or two years.
There will always be people who happen to see X-rays hitting barium cyanide platinate-like materials.
By then, Xu Yun has returned to his hometown peacefully(?).
In terms of time, there is a certain buffer period from the present day, which is undoubtedly a very exquisite arrangement.
Who could have imagined the result.
Wheat, who is not a martial artist, unexpectedly found the only vase in the house that was coated with barium cyanide platinate, and it happened to be in the path of the X-ray...
at the same time.
The Netherlands, a thousand kilometers away.
A small town called Apeldoorn.
In a kindergarten.
A little boy with an ordinary face who was preparing to take a nap suddenly stretched out his hand and grabbed the air.
Seeing this scene, the childcare worker not far away came over and asked:
"What happened?"
The little boy opened his mouth subconsciously.
For some reason, he suddenly felt empty in his heart, as if...
Something is generally lost.
But in the end, he still shook his head:
"I'm fine, Teacher Sanchi."
"Then let's take a nap first, Röntgen."
.............
－－－－－－Digression－－－－－
I recommend a book, "I Was a Guard in Britain". The plot is about the Ming Dynasty colonizing the world, oriental steampunk, mechanical technology and extraordinary power. It has some Cthulhu and SCP elements. If you are interested, you can check it out. Yes.