Chapter 2639 Wind and Flowers (18)

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

They estimated the time and found that "one month" had passed since the incident occurred. At that time, Remus Lupine had transformed before the full moon was actually reached.

"Speaking of prophecies, what did Sybil say this time?" Felivi suddenly asked while inspecting the scene.

"What?" Pomona asked.

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

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

"Is it because it records Sibyl's predictions like the prophecy ball?" Felivi said contentedly without waiting for Pomona to answer.

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

In ancient Greek mythology, there was a beautiful young man whose father was a river god and his mother was a fairy. Shortly after his birth, his mother received an oracle that he would become a handsome man when he grew up, but he fell in love with his own reflection and became depressed.

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 face.

Pomona also looked at "herself", but in her mind she recalled "herself" trying on clothes in the clothing store in Diagon Alley.

"Pomona!" Felivi suddenly shouted.

She looked at him in astonishment.

"Let's go back," Felivi said.

"No more investigation?" Pomona asked.

Felivi looked at the sky and said, "The evening star has risen."

Pomona also looked at the sky. The "evening star" that Felicius called 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 you compare the existence of a thing at a certain time and place with its existence at another time and place, you will

Forming identity and difference, like the morning star and the evening star.

Even though there are not as many Dementors in the Forbidden Forest as there were in the previous school year, the Eight-Eyed Spider is still a threat that cannot be underestimated.

After the interns can burn off the cobwebs and extinguish the fire with torrents, their next target is the eight-eyed spider, which is also Random's job. Although the eight-eyed spider is neither a "beast" nor a poacher

.

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 collection.

Pomona certainly wouldn't let him come to school to train his juniors in vain, 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 a time turner to take Harry back to this place that night. Everyone thought it was "Harry Potter without time travel" who summoned the Patronus.

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

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

"Go back," Felivi said, then turned and left.

Seeing him leaving, 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. She might as well wait until dawn before coming back.

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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. He also proposed the wave theory of light.

Newton was an admirer of the theory of light particles. As early as 400 BC, the Greek philosopher Democritus proposed the concept of atoms. If the atom is regarded as a Quidditch pitch, then the nucleus is only as big as a Golden Snitch.

, electrons are just a few grains of sand on the stand. There are large gaps in the atoms for photons to pass through, which makes the glass transparent. The object is opaque because the electrons absorb the energy of the photons and jump to a higher level.

energy level.

However, light slows down when passing through glass, only about two-thirds of the speed of light in a vacuum. When light penetrates the other side of the glass, it resumes the speed of light again.

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

There are two explanations. After entering the glass, the light particles continue to bounce off the atoms, causing the distance to become longer and the time it takes to increase. It looks like the speed of light has slowed down. But this explanation has a shortcoming. Photons travel between atoms.

The bounce is random and uncontrolled, and if so, the light entering the glass will not remain a beam and shine out from the other end, but will form scattering.

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

But the problem is that atoms don't "remember" which direction the photon came from. When it is released again, it also randomly chooses the direction, which will cause the light to scatter uniformly in the glass.

These are all based on the assumption that light is a particle. If we use light waves to explain it, when the peaks and troughs of the two waves are opposite, they will cancel each other out to form a new wave. The superposition of the light wave and the wave of glass electrons will form a wave that passes through the glass.

The speed of the wave is slower than that in vacuum. After the light leaves the glass, there is no wave of glass electrons, and the speed of light recovers.

The wavelength of visible light for most humans is between 400-700 nanometers. Light of this wavelength 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 human visible light wavelength range, but it can still take "photos".

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

Huygens' theory is to study the "spherical" wave surface and the reasons why waves turn and deviate from straight propagation after encountering obstacles. Sound waves are also a kind of wave that will rebound after encountering obstacles and then form an "echo".

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

In addition to refraction, glass can also reflect. Not only the metal behind the mirror has charged particles, but also the quartz, the material of the mirror itself. Various substances have different optical properties due to different distributions of charged particles. Comparing the images on the glass surface

"Virtual", what you see at the back is more "real". If the reflection of glass is the same as that of metal, why is there a need for a metal coating on the back?

Materials absorb light energy based on their molecular or atomic composition 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.

The wavelength of light waves is 660 nanometers for red waves and 550 nanometers for green light. In addition to mercury, humans have also used bronze and other materials as mirrors, but the color of copper mirrors is yellowish and cannot truly reflect the original color of objects.

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

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

She met many Dutch people during this trip, but only one person appeared in her mind.

"Madam." Matilda walked in with a sleepy face.

"Go and fetch Rutger," said Georgiana.

"Yes." Matilda curtsied.

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

"I'm not sleepy," said Matilda.

"You have other tasks when daybreak." Georgiana said, "Go to bed."

Matilda hesitated for a moment, then retreated.

When Georgiana was alone in the room, she began to practice yoga again, which seemed to refresh her mind.

This time she practiced the wheel pose. Although it is called a wheel, it is actually more like a bridge. It also evolved from the bridge pose.

Suppose there is a river in front of you, and there is an arch bridge on the river. The arch of the bridge in reality and the reflection in the water form a circle. The premise is that the river must be calm, at least it should look like this on the surface.
Chapter completed!