Chapter 2639 Wind and Flowers (18)

Before going back to school, Pomona and Felix went to the lake again.

They estimated the time, and it happened that "one month" had passed since the incident. At that time, Remus Lupine also transformed before the real full moon.

"Speaking of the prophecy, what did Sybil say this time?" Fei Liwei suddenly asked while inspecting the scene.

"What?" Pomona asked.

"I heard you took a crystal ball from her," said Feliway.

For a moment Pomona didn't know what to say.

"Is it because it recorded Sybil's prophecy like the prophecy ball?" Feliway said without waiting for Pomona's answer.

"You'd better ask Albus," said Pomona, and walked to the edge of the lake, looking down at the water, which reflected her face like a mirror.

In ancient Greek mythology, there is a beautiful boy whose father is a river god and mother who is a fairy. Soon after he was born, his mother received an oracle. He will grow up to be a beautiful man, but he is depressed because he falls in love with his reflection In the end, his mother tried every means to keep him away from streams, lakes and seas, so that he would never be able to see his own face.

Pomona looked at "myself" too, but her mind recalled "myself" trying on clothes in the tailor shop in Diagon Alley.

"Pomona!" Fei Liwei suddenly shouted.

She looked at him in astonishment.

"Let's go back." Feliwei said.

"No more investigations?" Pomona asked.

Feliwei looked at the sky, "The evening star has risen."

Pomona also looked at the sky. The "Evening Star" that Feliway mentioned was actually Venus. It was the same star as the "Morning Star", but it appeared at a different time.

Identity is contradictory. They have the same origin but contain different contents. If one compares the existence of a thing at a certain time and place with its existence at another time and place, it will Form identity and difference, like the morning star and the evening star.

Even if there were not as many dementors in the Forbidden Forest as there were in the previous school year, the eight-eyed spider was a threat not to be underestimated.

After the interns can burn the spider webs and use the torrent to extinguish the fire, their next target is the eight-eyed spider, which is also Random's job. Although eight-eyed spiders are neither "beasts" nor poachers.

At present, Random is still a "hit wizard". This profession is somewhat similar to Muggle swat. It specializes in combat and power control, and is not good at investigation and intelligence gathering.

Of course, Pomona would not let him come to the school to train his younger siblings for nothing, although he seemed to be in awe of Harry Potter who killed the basilisk at the age of 12.

No one knew that Hermione used the time-turner to bring Harry back to this place that night, and everyone thought it was "Harry Potter without time travel" who summoned the Patronus.

If it weren't for Felix, Hermione wouldn't have said so much, because it was too difficult to explain.

Regarding what happened that night, it is the "top secret" of Hogwarts, and even the teachers don't know much.

"Go back." Fei Liwei said, then turned and left.

Seeing him go, Pomona reluctantly left the lake.

Curiosity is not a sin, but we should treat it with caution.

She didn't think she should stay here alone to continue the investigation, but she should wait until dawn.

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The Huygens-Fresnel principle was proposed by the Dutch physicist Christian Huygens in the 17th century. He was an important pioneer between Newton and Galileo, and he also proposed the wave theory of light.

Newton was an advocate of the theory of light particles. As early as 400 BC, the Greek philosopher Democritus proposed the concept of atoms. If you think of an atom as a Quidditch pitch, the nucleus is only the size of a Snitch, and the electrons are a few grains of sand in the stands. There are large gaps in the atom that allow photons to pass through, which makes the glass transparent. Yes, the object is opaque because the electron absorbs the energy of the photon and jumps to a higher energy level.

But the light slows down as it travels through the glass, to about two-thirds the speed it travels in a vacuum, and regains its speed when it passes through the other side of the glass.

The speed of light in a medium is related to its refractive index.

There are two explanations. After light particles enter the glass, they are constantly bounced by atoms, resulting in longer distances and longer time spent. It seems that the speed of light has slowed down. But this explanation has a shortcoming. The bounce of photons between atoms is random and uncontrolled, and if so, the light entering the glass will not still be a beam and come out from the other end, but will form a scattering.

Another explanation is that the photon is absorbed by the atom in the mirror, and then released, absorbed, and released. It takes time for the atom to absorb the photon, and then the speed of light slows down.

The problem is that the atoms don't "remember" which direction the photon came from, and when it re-emits it chooses a random direction, which causes the light to scatter evenly in the glass.

These are all based on the assumption that light is a particle. If it is explained by light fluctuations, when the peaks and troughs of the two waves face each other, they will cancel each other out to form a new wave. The superposition of light waves and glass electron waves will form a wave that passes through the glass. A wave that travels slower than in a vacuum. After the light leaves the glass, there is no wave of glass electrons, and the speed of light is restored.

The wavelength of visible light to most humans is between 400-700 nanometers, this wavelength of light is "opaque" to metals, x-rays have strong penetrating power, and can penetrate most metals except lead Transparent, its wavelength is 10 nanometers, which is not within the wavelength range of human visible light, but it can still take "photos".

Waves propagate in a straight line in a homogeneous medium, so the mirror reflects light because the mirror "bends" the wave?

Huygens's theory was to study the "spherical" wave surface and the reason why the wave bends after encountering obstacles and deviates from straight-line propagation. A sound wave is also a wave that bounces off an obstacle, creating an "echo".

The surface of the crystal ball is of course different from the surface of the flat glass, as the reflection of a person on the crystal ball and the glass can be seen.

In addition to refraction, glass can also reflect. Not only the metal behind the mirror has charged particles, but even the quartz material of the mirror itself has charged particles. Various substances show different optical properties due to the different distribution of charged particles. The image on the surface of the glass is relatively "virtual", while the image behind it is more "real". If the reflection of glass is the same as that of metal, why is there a need for a metal coating behind it? ?

Matter will absorb light energy according to the composition of molecules or atoms, and release it through radiation and heat energy. The wavelength of reflected light is the wavelength of light that people see. Red objects absorb light waves other than red, and green objects absorb light waves other than green. Light waves, the wavelength of red light is 660 nanometers, and the wavelength of green light is 550 nanometers. In addition to mercury, humans have also used bronze and other materials as mirrors, but the color of the bronze mirror is yellowish, which cannot truly reflect the original color of the object.

Gold is similar to many substances in color, such as brass and iron sulfide. It is almost difficult to distinguish them just by looking at the color and shape. The wavelength of gold is about 595 nanometers, but it is also easy to distinguish them, which requires "knowledge".

Georgiana rang the bell. It was Leeuwenhoek who discovered the cochineal and cracked the secret that Spain had kept for many years. It was also the Dutch physicist who proposed the theory of light fluctuations. She felt that she had to summon a Dutchman.

She had met a lot of Dutch people during this trip, but only one person came to her mind.

"Ma'am." Matilda walked in with a sleepy face.

"Go get Rutger," said Georgiana.

"Yes." Matilda curtseyed.

"You can rest," Georgiana said after she stood up. "Go and get Figo."

"I'm not sleepy," said Matilda.

"You've got other things to do in the morning," Georgiana said. "Go to sleep."

Matilda hesitated, but withdrew.

After Georgiana was alone in the room, she started practicing yoga again, which seemed to have a refreshing effect.

This time she practiced Wheel Pose. Although it is called Wheel, it is actually more like a bridge, and it itself evolved from Bridge Pose.

Suppose there is a river in front of you, and there is an arch bridge on the river. The actual bridge arch and the reflection in the water form a circle. The premise is that the river must be calm, at least on the surface.