Chapter 389 Yang’s double-slit interference experiment! Create the weirdest quantum experiment in the future!
Physics Olympiad experimental questions officially begin!
For the European players, although they just performed very shocked.
But I was secretly happy inside.
Because this kind of competition is really difficult for them.
No one can guarantee that it will be completed.
But for Asian players, it is even more difficult.
For example, the members of the Philippine Fishing Team have never even seen some of the instruments with their own eyes.
Of course, I have seen it in books.
So, this is a game with an inherent gap.
Nobuji Komura cursed, blaming Professor Bohr for being too clever and changing the title like this.
Otherwise, Professor Li Qiwei would only look at simple experiments when looking after Asian players.
Poor students think too much, and this is clearly reflected in Xiao Cun.
Always thought someone was harming him.
When Wu Youxun entered the competition room, the first thing he felt was emotion.
Although he did not hear the conversation between Bohr and Li Qiwei.
But as smart as he is, he can instantly figure out what these instruments are used for.
After all, it would cost a lot of money to build so many instruments just for one competition.
This is definitely not the principal's style.
Although the principal is very wealthy and uses money as paper, he never wastes a dollar or a dime.
All the money he spent was not for his own enjoyment and face, but for China's education and technology career.
So, there is no doubt that these instruments will be donated after the competition.
Don’t think about it, it must be donated to universities in China.
But there is one thing that Wu Youxun can't understand.
Why doesn’t the principal directly develop in the country?
Instead, there is an extra link to Borneo.
As a principal, it should be easy to become the Minister of Education in China.
It’s okay to even be the Minister of Science and Technology.
Are you worried about the current warlord war in the country?
Wu Youxun shook his head and stopped thinking about this.
The principal's level is too high. He, a young Karami who has not yet graduated from a bachelor's degree, cannot understand it for the time being.
You should concentrate on completing the next game.
So, he took a deep breath and walked to the experimental table calmly.
First nod and say hello to the recorder in the corner, and then start writing the experimental plan.
Wu Youxun drew Experiment 3: Yang’s double-slit interference experiment.
When he first saw the name of this experiment when he was in school, he thought it was an experiment done by a Chinese named Yang.
Unexpectedly, he was Thomas Young, an Englishman.
The status of this experiment in the history of physics should be elevated no matter how high it is.
At that time, it not only provided strong evidence for the wave theory of light.
In the future, it will provide experimental ideas for verifying the behavior of a single photon or electron.
This laid a solid experimental foundation for the establishment of quantum mechanics.
In general.
If it is called "Young's Double Slit Interference Experiment", it specifically refers to the optical experiment done by Thomas Young.
If it is called "double slit experiment", it generally refers to the single electron double slit experiment.
This experiment was famous in Li Qiwei's previous life.
Countless civilian science and marketing accounts have given various so-called subversive interpretations.
Unfortunately, everything is wrong.
Li Qiwei: Don’t worry, I will explain it later.
Some people even connect the wave-particle duality of electrons with Buddhism.
There is a saying in Mahayana Buddhism: All living beings have Buddha nature, and all things have Dharma nature.
Whether it is Buddha-nature or Dharma-nature, they are both the wonderful and true nature of the Tathagata.
That is, the Buddha-nature and Dharma-nature are unified and non-dual.
One is all, all is one.
The behavior of electrons shows that they are spiritual, know their past and future, and control their own destiny.
It sounds unclear.
It’s no wonder that many people like to think that the end of science is metaphysics.
Because metaphysics does not require formulas, everyone can understand it.
Although the process of the single-electron double-slit experiment is very simple, it was not done until the 1960s.
Einstein wanted to do this experiment at the time, but technological development could not keep up.
Scientists at that time were unable to control and emit individual photons or electrons.
And Li Qiwei may be able to make up for this regret.
He really wanted to do the double-slit interference experiment of single electrons and even the delayed selection experiment in advance.
Sitting and discussing with the top bosses of this era.
That scene must be more shocking than the fifth Solvay Conference in real history.
The secrets of quantum mechanics still fascinate all physicists in later generations.
Because it is likely to hide the ultimate truth of the universe.
If relativity explains space and time, then quantum mechanics explains matter.
And it all started with a simple experiment.
The principles and steps of Young's double-slit interference experiment seem to be very simple indeed.
One sentence can sum it up:
[After the light source passes through two adjacent slits, interference will occur, forming alternating light and dark stripes on the light screen. 】
But when it comes to specific details, students who have not studied carefully may be confused.
For example:
First, what kind of light source can be used to perform a double-slit interference experiment? How to get it in Thomas Young's day?
Second, how to determine the distance between two gaps and the width of a single gap? How do they affect experimental results?
etc.
So, say the thread makes tears.
Thomas Young did this experiment in the early 19th century, when there was no light source generator.
So, he opened a small hole in the window to let the sun shine in, using the sun as a light source.
Sunlight is white light, which is incoherent light.
Although double-slit interference experiments can also be done with sunlight, the coherence is too poor and only zero-order fringes can be seen.
So Thomas used a prism to decompose sunlight and obtain monochromatic light.
The coherence of monochromatic light is far superior to the white light of the sun.
Next, he let the monochromatic light pass through a small hole S1 to further improve the coherence.
Then, he made two very close pinholes S2 and S3 on a very thin piece of paper.
The monochromatic light passing through S1 passes through S2 and S3 respectively after passing a certain distance.
In this way, the light passing through S2 and S3 comes from the same monochromatic light source of the S1 hole.
As a result, interference will occur on the blackboard behind S2 and S3, forming alternating light and dark stripes.
This was the experimental process of Thomas Young at that time.
In real history, he also experimented with white light, but the effect was not very good.
Up to now, physicists have changed the small holes into slits to obtain better experimental results.
In the future, lasers will appear, and the coherence of the light source will be greatly improved.
And thanks to the development of micro-nano technology, physicists can create slits that are only a few hundred nanometers wide.
This width is basically the same as the wavelength of visible light, and the interference effect that occurs is extremely obvious.
The accuracy of Young's double-slit interference experiment has been greatly improved.
Now, what Wu Youxun has to do is to repeat this experiment and obtain interference fringes.
On the experimental table in front of him, various instruments were placed, as well as the given slits.
He needs to calculate the distance between S1 to S2 and S3 by measuring the size of the slit.
At the same time, there are also parameters such as the distance from S2 and S3 to the light screen, the distance between slits, and so on.
For students in this era, this is not a simple project.
Soon, Wu Youxun devoted himself to the experiment.
At the same time, Irena, Rancher and others also started their own experiments.
Irena chose Experiment 2: Cavendish Torque Experiment. The purpose of this experiment is to measure the gravitational constant G.
It was an experiment conducted by the British physicist Cavendish at the end of the 18th century.
Yes, this Cavendish is the one who founded the Cavendish Laboratory at Cambridge University.
It can also be regarded as the ancestor of Li Qiwei, Rutherford, Wilson and others.
This experiment is very cleverly designed.
To put it simply, it is to first fix a silk thread vertically.
Then hang a long rod horizontally at the end below the silk thread, thus forming a torsion scale.
At both ends of the long pole, hang a shot put A (the mass is known).
Record the long pole position at this time.
Next, place shot put B next to the two shot put A.
Due to the gravitational force between A and B, the angle of the long rod will deflect.
Based on the deflection angle, shot mass and other data, the universal gravitational constant can be calculated.
This experiment also seems very simple.
But in actual operation, it is very difficult.
It took Cavendish more than half a year to get perfect data.
Because there are too many error factors, it will cause problems with the results.
The gravitational force between the shot put is too small, so the impact of error is great.
How to effectively eliminate errors is the key to this experiment.
Despite this, Irena still smiled.
She felt that she was lucky. In her opinion, this experiment was much simpler than the other three.
The most important thing is that there will be no big mistakes.
Ranche chose Experiment 4: Faraday’s electromagnetic induction experiment.
This experiment demonstrates that a changing magnetic field can produce an electric field.
It had a profound influence on Maxwell's later unification of electricity and magnetism.
Its importance is self-evident, and it can be said that it is closely related to the start of the second industrial revolution.
Humans have since mastered electricity and magnetism.
The changes that electricity and tape have brought to the human world are earth-shaking.
Far beyond the role of the steam engine.
Ranche is very familiar with this experiment.
He was even sure of getting full marks.
After all, his first self-made experiment in college was related to electricity.
Electricity, magnetism, and mechanics are all things he is good at.
Ye Qisun chose experiment five: Joule heat work equivalent experiment.
This experiment proves the equivalence of heat and work.
Joule’s experiment is also very clever.
He installed propeller blades in a bottle filled with water.
A heavy object is tied to the other side of the propeller away from the water bottle.
When the weight drops, it drives the propeller and stirs the water in the bottle, thereby increasing the temperature of the water.
Measuring the temperature rise of water can calculate the heat required by the water.
Then compare the work done by the falling weight with the heat required to heat the water, and you get the thermal work equivalent.
The value of heat work equivalent is actually the specific heat capacity of a substance.
After Ye Qisun got the question, he breathed a sigh of relief.
What he feared most was Young's double-slit interference experiment and Faraday's electromagnetic induction experiment.
As for Joule’s experiment, Ye Qisun is very confident.
He secretly cheered in his heart, "The experimental questions should be stable now."
Unfortunately, the other three Ding Xubao chose the two experiments that Ye Qisun was afraid of.
As a result, the game immediately became confusing.
The innate advantages of the European teams mean that their scores on the experimental questions must be very high.
Although the five members of the Chinese team are confident, they also know that this gap cannot be caught up by relying on explosive seeds.
Experiments are all about taking things slowly and steadily.
As long as they don’t make mistakes.
With the big brother Wu Youxun pulling points from the front.
As long as the four of them can hold their own, and the group does not aim for first place, at least the top three can still work hard.
So, the extremely nervous Physics Olympiad experimental questions began.
80 players are in 80 separate rooms.
Each room has a dedicated recorder who is responsible for recording their operating steps.
The heads of delegations from various countries walked into each room from time to time to inspect the experiments of the players.
At the same time, they will also check the recorder's records to ensure accuracy.
It can be said that this game has reached the ultimate level of this era.
Just when everyone is performing their duties to ensure the smooth progress of the game.
Li Qiwei has returned to Wuya Pavilion.
He is preparing for the awards for the first Physics Olympiad.
Olympiad rewards in real history are based on proportion.
The gold medal should be awarded to 8% of the contestants.
Gold and silver medals shall be awarded to 25% of the participants.
Gold, silver and bronze medals shall be awarded to 50% of the participants.
And Li Qiwei is simple and crude.
Just take the top three.
First the top three in the group.
There are only conventional honorary awards such as gold medals, bronze medals, and silver medals.
At the same time, in order to express the importance and active participation of various countries in the first Olympiad.
He will present a set of experimental instruments to each participating country as a souvenir.
Then there are the top three individuals.
In addition to the gold, silver and bronze medals.
Li Qiwei will also give a special award to the gold medal winner.
This is the so-called mysterious gift.
This was his public promise before the game.
At that time, it was just to enhance the gimmick of the competition, and Li Qiwei really didn't think about what the special prize would be.
Now the game is about to end.
It is estimated that the results of the competition will be announced in half a month.
So, he needs to start preparing.
“Money? Too vulgar.”
"Quan, I am not qualified to be knighted."
Li Qiwei racked his brains and finally came up with the most vulgar one.
Anyway, with his current status, he should be qualified to give such a reward.
He told Wang Zhengyang about the award plan.
Let the opponent announce it in the Science Museum after today's game.
Due to the special nature of the award, the award cannot be announced until the winner is confirmed. It needs to be announced in advance.
Wang Zhengyang was very shocked after reading it.
"Principal, isn't this special award a bit too amazing?"
"In case, just in case"
Li Qiwei smiled: "Are you Worrying if the gold medal winner is not our Chinese team.”
"This award will be out of control."
Wang Zhengyang nodded.
Li Qiwei stood up, looked out the window, and said domineeringly:
"It doesn't matter, everything is under my control."
(End of this chapter)