Then, Zhao Xingsheng saw Gu Xiaobai checking information with his mobile phone while writing calculations on paper.

The flute, or the Chinese flute, the bamboo flute, is divided into "Bang Di" and "Qu Di", the two are the northern flute and the southern flute, the northern flute was originally with the northern Bangzi, shorter, smaller, sharp and high-pitched timbre, mainly tongue skills;

In fact, there is no strict difference between the two, only the tone is different, from the structural point of view, both include the flute body, the plug, the blow hole, the membrane hole, the 6 finger holes, the base sound hole, the sound aid hole and the plug, and some have metal interfaces that can fine-tune the sound. In addition, there are decorative silk winding, tassels, inlays and so on.

If you want to make a flute, you don't just have to drill these holes in the bamboo, and it's not easy to make every note accurate.

Zhao Xingsheng didn't know how to make flutes himself, but he had seen some flute makers operate them in his early years.

First, make a blow hole in a flute, usually a bitter bamboo or a "three-year purple" purple bamboo, and then plug the flute plug on one side to block one end so that the air flow only passes to the other side.

Then open the base sound hole. Start to drill a small hole first, blow while expanding, the earpiece sound is not correct, if the tube tone is low, the hole will be a little bigger on the side of the blowing hole, and if it is high, it will be opened to the other side, so drill out the base sound hole.

Then proceed to open the finger hole......

Drill one by one, try one by one, and if you are not careful, a good flute material will be wasted, which makes people feel embarrassed.

In fact, without years of experience, you don't even know where to open the first blow hole.

Therefore, many bamboo flutes must be written to be supervised by famous artists to prove their pitch and noble status.

In this way, Gu Xiaobai actually wanted to make his own flute?

This kid doesn't know how easy it is to say or how hard it is to do, does it?

Then he heard Gu Xiaobai muttering softly: "Hmm, this is the problem of turbulent vibration caused by the cylinder under a circular section......

As he spoke, he opened the knowledge network.

It's the first time Zhao Xingsheng has seen someone making a flute while checking papers!

His eyes widened and he curiously approached Gu Xiaobai's side.

Then he heard Gu Xiaobai muttering:

"Let the inner diameter of the flute be D and the length be L. ”

L0 is the distance from the gene hole to the blow hole, L1 is the distance from the first finger hole to the blow hole, and L2 is the ...... The distance from the blown hole to the membrane hole is Lm......"

"The ratio between the inner diameter D and L0 is about 20."

"The distance between the blow hole and the finger hole Li(i=0,1,2,...... , 6) fi with the fi frequency (i=0,1,2...... ,6) according to the formula Li=v/2fi-ΔL(i=0,1,2,...... and 6) Calculations.

"where V is the speed of sound, the speed of sound is related to the temperature, the average value of 25 degrees, the speed of sound is 345700mm/s. ”

Seeing that Zhao Xingsheng was looking at him, Gu Xiaobai also raised his head and explained:

"The relationship between the resonance frequency f and the length l of the two ends of the open tube is Li=v/2f, but the vibration of the cylinder and the vibration of the chord are different, so there is also a problem of air vibration at the edge, so a correction compensation length ΔL is added, according to the research data, this ΔL=4D (mm) is more appropriate......"

Zhao Xingsheng shook his head and said, you don't have to explain it to me!

I don't want to hear it at all!

I can't understand it!

If you understand it, you won't use it!

I won't say it!

I just want to sacrifice my knees to survive like this!

He already roughly understood why Gu Xiaobai was able to read a music theory primer so quickly...... For a physics tyrant, the interval conversion in music theory, the circle of fifths and the like, is it just too pediatric, okay?

"Alright, done. ”

Then he saw Gu Xiaobai write down an exceptionally short formula on the paper, and then redrew it with a pen.

"Okay, just find a piece of bamboo, and then substitute its inner diameter, you can calculate the distance from each hole to the blowing hole, and then punch the hole directly. ”

Zhao Xingsheng was stunned.

"That's it?"

"It's over. ”

"What kind of flute can you tune like this?"

"From A to G, you want a flute in whatever tune you want, even a flute that is not in a tune, and you can make whatever frequency you want. Gu Xiaobai pinched his chin, his eyes shining.

His eyes only light up when physics is mentioned.

It's even brighter than when you're singing on stage.

Zhao Xingsheng picked up the blank paper in front of Gu Xiaobai.

The formula is not long, and the calculation process does not exceed 20 lines from beginning to end.

Simple, straightforward and clear, there is a strange beauty.

But this formula is enough to make countless craftsmen pursue it for a lifetime but it is hard to get it.

He only felt that if the flute master who had been immersed in it all his life saw Gu Xiaobai's formula, he would definitely fall to the ground and never want to get up again.

Can anyone tell me why a musical problem, in the blink of an eye, has become such a simple formula.

As a historian, he also knows that physics can solve many problems.

But...... When this kind of thing really came to him.

"It's good that I'm a liberal arts student! I don't have to live with this pervert. ”

He was very happy, very happy!

Gu Xiaobai can't wait to see if his data is correct, just like every physicist who has completed a theory can't wait for someone to confirm him with experiments.

"Teacher......" he asked, "Do you say that if I go to the school's bamboo garden now and steal a piece of bamboo, I will be arrested by the police uncle?"

"Yes. "Zhao Xingsheng really wants to touch Gu Xiaobai's head, is this kid stupid?

"Then, teacher, will you help me let the wind out?"

"What the hell are you thinking!" Zhao Xingsheng really shouted, "It's not early, go back to sleep!"

"Hmm...... Then I'll run to steal ...... tomorrow morning" Gu Xiaobai refused to give up his criminal plan at all, "Teacher, if I am arrested by the police uncle, can you take me out?"

Gu Xiaobai looked at Zhao Xingsheng, looking like he was all relying on you.

"I ......" Zhao Xingsheng wanted to refuse, wanted to say no.

How can I support you to commit a crime! Xiaobai, you are the hope of the whole school, and you are a candidate for the hundred sons of the campus!

"I'm going to steal bamboo early tomorrow morning, teacher, you must turn on your mobile phone in the morning!"

Gu Xiaobai said.

Zhao Xingsheng felt that it was over, such a good seedling, for the sake of a bamboo flute, he would embark on the road of crime from now on, go to prison, and hate for life......

Xiaobai, Xiaobai, for the sake of physics, you are not worth it, you are not worth it!

Gu Xiaobai's impatient appearance shocked the system.

Is this still the Gu Xiaobai who has no interest in music and even wants to give up?

Sure enough, Gu Xiaobai has fallen in love with music!

Great, I won't be swept away!

But...... Why is this change happening?

Could it be the charm of crime?!

The system felt that he should support Gu Xiaobai's crime.

"Additional Teaching Task: Making a Bamboo Flute. Successful bamboo flute production rewards passive training of beginner bamboo flute playing skills. ”

Note 1: At present, there are only some sound hole size comparison tables on the Internet, and it is explained that it is still necessary to fine-tune when making a flute.

Note 2: The formula comes from Professor Wu Jike, a retired professor of physics and doctoral supervisor of Peking University, to pay tribute to the elderly.

Note 3: The actual situation of the instrument is much more complicated than the formula, especially the control of pitch and timbre, but Uncle Ha is not writing a paper~ That's it, perfect!