Talking About Physics with a Mermaid

Rhine chatted smoothly with the surrounding mermaids.

This "strange creature without a tail" briefly explained where they came from.

After asking a few simple questions and confirming that the underwater kingdom was not much different from what was described in the book, he lavishly praised the Sea King's power, extolled the magnificence of the Sea King's Palace and gardens, complimented the Sea King's mother, the "Old Grandmother's" wisdom, and praised the beauty and nobility of the mermaid princesses.

He was so skilled and familiar that he didn't seem like a visitor entering the Sea Kingdom for the first time, but rather like a guide who frequently traveled to and from the Sea Kingdom.

Before long, the mermaids became quite familiar with Rhine.

They talked about everything under the sun. Rhine behaved like those learned Magicians in stories, answering the mermaids' strange questions about the world above one by one.

For example, one mermaid asked:

"Why can the fish in your upper world swim even when they are not in the water?"

Aurora was completely baffled by this.

There were no fish in the human world that could "swim even when they are not in the water"!

Rhine immediately told the little mermaid:

"In the human world, we don't call those creatures fish—although they do fly over our heads just like the fish here—we call them 'birds'. Birds can fly because they have a pair of wings, and wings are to air as fish tails and fins are to water."

Aurora was immediately stunned and looked at Rhine suspiciously.

Wait, how did he know she was asking about birds? Another little mermaid asked, "I heard from a friend who once went above the sea that in your world, the Moon and stars are smaller but brighter than in our world. Why is that?"

"Do the Moon and stars shrink when they see you humans?"

What? The stars and Moon in the sea world are bigger than the stars and Moon in the human world? Wait, are there stars and Moon in the sea world? Aren't they all in the sky? Aurora was completely confused.

Rhine smiled and patiently explained to the mermaid, "It's an optical illusion caused by the refraction of light. In other words, your eyes are deceiving you."

When viewing the stars and Moon in shallow seawater, the light they emit is much weaker, but through a layer of water, the Moon in the mermaid's eyes is much larger than in human eyes! (Note 1)

He even took out paper and pen on the spot, drew the path of light, the angle of incidence, and the angle of refraction, explaining the changes caused when light enters the water, to illustrate the difference between the world in the eyes of mermaids and the world in the eyes of humans, and the many problems caused by this difference in perspective.

Aurora barely understood the physics knowledge Rhine explained, marveling at her teacher's vast knowledge and sighing at the world's hidden secrets—seeing is not necessarily believing.

But the mermaids, who had never been to school, were extremely confused.

They just praised him repeatedly, feeling that although they didn't understand it, it was very powerful and must be profound knowledge.

The human boy who was talking to them must be a learned scholar from the upper world! "So, although we who live in the sea don't understand the humans in the upper world, humans understand us so well!"

"I thought we hadn't had much contact with humans. I thought humans knew nothing about us, about His Majesty the Sea King, about this sea kingdom, and about the world in our eyes!"

"Human knowledge is so profound and vast! Although I can't understand it, it seems very powerful."

The mermaids sighed after chatting with Rhine.

Seeing this scene, Aurora loudly retorted in her heart: "No, that's not right! Teacher cannot be taken as an example of humans!"

"Most humans know nothing about the mermaid kingdom, nor would they study such wonderful knowledge or discuss the differences between mermaid and human perspectives."

Turning to look at Rhine, who was chatting happily with the mermaids, Aurora was extremely puzzled.

Teacher, is this really your first time in the Sea Kingdom? Rhine seemed to know Aurora's confusion and explained while recalling:

"I once read a novel whose protagonist was a race living in the sea, which provided a perspective and way of looking at the world from the perspective of marine creatures, a different perspective from us humans.

"I am putting myself in the perspective of the mermaids and using their way to understand their questions.

"In the novel, the author compared schools of fish to birds—in fact, this is similar. Just as humans can look up and see flocks of birds of different colors flying by, mermaids can also look up and see flying birds.

"The novel also said that marine creatures see the Moon in shallow seas much larger than humans see it!"

"Many years ago, when I first read this passage, I was very surprised. I used my knowledge to draw the path of light and studied it for a long time before I was sure that the author had not made a mistake."

The boy couldn't help but smile as he said this, his eyes revealing memories and reluctance. This reminded him of the years before he came to this continent.

After their questions were answered, the mermaids curiously asked this "new friend without a tail": "Humans on land, what are you here in the sea for?"

Rhine took the opportunity to state his purpose:

"We are here to find a Sea Hag, a Sea Witch who is proficient in Black Magic. We need her to do us a small favor. You must know where she is, right?"

The little mermaids' expressions changed drastically when they heard the two humans' intentions, and they were extremely suspicious: "No way?"

"They're actually here to find that Sea Hag!"

"Someone actually dares to look for her?"

"Even we Mermaids of the sea don't dare to look for her! How can humans on land be so bold?"

"Don't go! She's a terrifying being who is proficient in Black Magic. There's definitely no good outcome from seeking her help."

"..."

Note 1: Mermaids see celestial bodies larger from the water. At least, that's what Andersen said. I spent 10 seconds quickly imagining the refraction diagram, and it seems to be like that. If there's a mistake, it's Andersen's fault.