1900: A physics genius wandering around Europe

Chapter 389 Young's double-slit interference experiment! Creating the most bizarre quantum experiment in the future!
The Physics Olympiad experiment questions officially begin!
For the European players, although they just performed very shockingly.

But inside I was secretly happy.

Because this kind of competition is indeed difficult for them.

No one can guarantee that it can be completed.

But for Asian players, it is even more difficult.

For example, members of the Philippine fish bombing team had never even seen some of the instruments.

Of course, I have seen it in books.

So, this is a game with an innate gap.

Shinji Omura cursed and blamed Professor Bohr for being so smart by changing the question like this.

Otherwise, Professor Li Qiwei would have only examined simple experiments to take care of the Asian players.

Poor students think a lot, and this is fully reflected in Xiaocun.

He always thought someone was harming him.

When Wu Youxun entered the competition room, the first thing he felt was moved.

Although he did not hear the conversation between Bohr and Ridgway.

But as smart as he is, he can instantly figure out what these instruments are used for.

After all, it would be a waste of money to build so many instruments just for one competition.

This is definitely not the principal's style.

Although the principal is rich and treats 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.

Therefore, there is no doubt that these instruments will be donated after the competition.

There is no doubt that it was donated to a university in China.

But there was one thing that Wu Youxun couldn't understand.

Why doesn’t the principal develop directly in the country?
Instead, there is the additional link of Borneo.

As a school principal, it should be easy for him to become an education minister in China.

There is even no problem with him serving as Minister of Science and Technology.

Are they worried about the current warlord infighting in the country?

Wu Youxun shook his head and stopped thinking about it.

The principal's realm was too high, and Karami, who had not yet graduated from college, could not understand it for the time being.

I should just concentrate on finishing the next game.

So he took a deep breath and walked calmly to the laboratory table.

First nod and say hello to the recorder in the corner, then start writing the experimental plan.

Wu Youxun drew experiment three: Young’s double-slit interference experiment.

When he first saw the name of this experiment at school, he thought it was an experiment done by a Chinese named Yang.

Unexpectedly, the person turned out to be Thomas Young, a British man.

The status of this experiment in the history of physics deserves to be elevated no matter how high it goes.

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 single photons or electrons.

This laid a solid experimental foundation for the establishment of quantum mechanics.

Generally speaking.

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 the "double-slit experiment", it generally refers to the single-electron double-slit experiment.

This experiment was very famous in Li Qiwei's previous life.

Countless amateur scientists and marketing accounts have given various so-called subversive interpretations.

Sadly, they are all wrong.

Li Qiwei: Don’t worry, I will explain it later.

Some people even link the wave-particle duality of electrons with Buddhism.

Mahayana Buddhism says: All sentient beings have Buddha nature, and all things have Dharma nature.

Whether it is Buddha nature or Dharma nature, they are all the wonderful true nature of Tathagatagarbha.

That is, the Buddha nature and the Dharma nature are one and the same.

One is everything and everything is one.

The behavior of electrons shows that they are spiritual, know their past and future, and control the trajectory of 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 simple, it was not performed until the 20s.

Einstein wanted to do this experiment very much at the time, but technology was not developing fast enough.

Scientists at the time were unable to control and emit individual photons or electrons.

And Li Qiwei may make up for this regret.

He really wanted to carry out the single-electron double-slit interference experiment and even the delayed choice experiment in advance.

Sit down and discuss with the top bosses of this era.

That scene must have been even more shocking than the Fifth Solvay Conference in real history.

The secrets of quantum mechanics continue to haunt all physicists in later generations.

Because it may very well 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 very simple indeed.

It can be summed up in one sentence:

[When light passes through two adjacent slits, interference occurs, forming light and dark stripes on the light screen.]

However, when it comes to specific details, students who have not studied seriously may be confused.

such as:

First, what kind of light source is needed to perform the double-slit interference experiment? How could it be obtained in Thomas Young's time?

Second, how to determine the distance between the two slits and the width of a single slit? How do they affect the experimental results?

and many more.

So, the line is tears.

Thomas Young performed this experiment in the early 19th century, when there were no light generators.

So he made a small hole in the window to let the sunlight in and used it as a light source.

Sunlight is white light, that is, incoherent light.

Although sunlight can also be used for double-slit interference experiments, the coherence is too poor and only zero-order fringes can be seen.

Therefore, Thomas used a prism to decompose the sunlight and obtain monochromatic light.

The coherence of monochromatic light is far superior to the white light from the sun.

Next, he let the monochromatic light pass through a small hole S1 to further improve the coherence.

Then, he made two closely spaced pinholes S2 and S3 on a very thin piece of paper.

The monochromatic light passing through S1 passes through S2 and S3 respectively after traveling a certain distance.

In this way, the light passing through S2 and S3 comes from the same monochromatic light source, hole S1.

As a result, interference will occur on the blackboard behind S2 and S3, forming alternating light and dark stripes.

This was Thomas Young's experimental process at the time.

In real history, he also experimented with white light, but the results were not very good.

Up to now, physicists have changed the small holes into slits, achieving better experimental results.

In the future, lasers appeared and the coherence of light sources was 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 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 and the given slits were placed.

He needs to calculate the distance from S1 to S2 and S3 by measuring the size of the slits.

There are also parameters such as the distance from S2 and S3 to the light screen, the distance between the slits, etc.

This is not an easy project for students of this era.

Soon, Wu Youxun devoted himself to the experiment.

At the same time, Irena, Rancho 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 British physicist Cavendish in the late 18th century.

That’s right, this Cavendish is the one who founded the Cavendish Laboratory at the University of Cambridge.

He can be considered the ancestor of Ridgway, Rutherford, Wilson and others.

This experiment was very cleverly designed.

To put it simply, first fix a silk thread vertically.

Then a long rod is hung horizontally at the end below the silk thread, thus forming a torsion balance.

A lead ball A (of known mass) is hung at each end of the long rod.

Record the position of the long rod at this time.

Next, place shot put B next to the two shot put A's.

Due to the gravitational force between A and B, the angle of the long rod will be deflected.

Based on data such as the deflection angle and the mass of the shot put, the gravitational constant can be calculated.

This experiment also looks 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, the results will be problematic.

The gravitational force between the shot put is too small, so the impact of the error is very large.

How to effectively eliminate errors is the key to this experiment.

Despite this, Irena still smiled.

She felt that she was lucky, as this experiment seemed much simpler to her than the other three.

Most importantly, no big mistakes will occur.

Rancho chose experiment 4: Faraday's electromagnetic induction experiment.

This experiment demonstrated that a changing magnetic field can generate an electric field.

It had a profound impact 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.

From then on, humans mastered electricity and magnetism.

Electricity and magnetic tapes have brought about earth-shaking changes to the human world.

It far exceeds the function of the steam engine.

Rancho was very familiar with this experiment.

He was even confident of getting full marks.

After all, his first homemade experiment in college was related to electricity.

Electricity, magnetism, and mechanics are all things he is good at.

Ye Qisun chose Experiment 5: Joule's equivalent of heat to work experiment.

This experiment demonstrated the equivalence of heat and work.

Joule's experiment was also very ingenious.

He installed a propeller blade in a bottle of water.

A weight is tied to the side of the bottle where the propeller leaves.

When the heavy object drops, it drives the propeller, stirring the water in the bottle, thereby raising the temperature of the water.

By measuring the temperature rise of the water, the amount of heat required by the water can be calculated.

Then, by comparing the work done by the falling weight and the heat required to heat the water, we get the heat-work equivalent.

The value of the mechanical equivalent of heat is actually the specific heat capacity of the substance.

After Ye Qisun got the question, he breathed a sigh of relief.

What he feared most were Young's double-slit interference experiment and Faraday's electromagnetic induction experiment.

As for Joule's experiment, Ye Qisun was very confident.

He cheered himself up in his heart, "This time the experimental questions should be easy."

Unfortunately, Ding Xubao and the other two chose the two experiments that Ye Qisun was afraid of.

As a result, the game immediately became confusing.

The inherent advantages of the European teams will ensure that they will score very high on the experimental questions.

Although the five members of the Chinese team were confident, they also knew that this gap could not be made up by just bursting out of energy.

Experiments require steady and cautious progress.

They just have to not make mistakes.

With big brother Wu Youxun pulling the points in the front.

As long as the four of them can keep steady, they don't have to aim for first place in the team points, but they can at least strive for the top three.

Thus, the extremely tense Physics Olympiad experiment began.

There are 80 contestants, each in an independent room.

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 contestants' experimental conditions.

At the same time, they will also check the recorders' records to ensure their accuracy.

It can be said that this game has reached the pinnacle of this era.

Just as everyone was doing their job to ensure the smooth progress of the competition.

Li Qiwei has returned to Wuya Hall.

He has to prepare for the awards for the first Physics Olympiad.

In real history, the rewards for the Olympic Games were based on proportions.

Gold medals should be awarded to 8% of the participants.

Gold and silver medals should be awarded to 25% of the contestants.

Gold, silver and bronze medals shall be awarded to 50% of the participants.

But Li Qiwei was simple and crude.

Directly take the top three.

First up are the top three teams.

There are only conventional honorary awards such as gold, bronze and silver medals.

At the same time, in order to express the importance and active participation of all countries in the first Olympiad.

He will give a set of experimental equipment to each participating country as a souvenir.

Then there are the top three individual finishers.

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 a promise he made publicly before the game.

At that time, it was just to increase the gimmick of the competition, and Li Qiwei really hadn't figured out 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? That's too vulgar."

"Quan, I am not qualified to be knighted."

Li Qiwei racked his brains and finally came up with the most vulgar idea.

Anyway, with his current status, he should be qualified to give such a reward.

He told Wang Zhengyang about the award plan.

Let the other side announce it in the Science Museum after today's game.

Due to the special nature of the award, the announcement cannot be made until the winner is confirmed, and needs to be announced in advance.

Wang Zhengyang was shocked after reading it.

"Principal, isn't this special award a little too... too surprising?"

"Just in case, just in case"

Li Qiwei smiled and said, "Are you worried that the gold medal winner might not be from our Chinese team?"

"This award is going to 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)