Su Ji, who was grumbling with hunger, didn't pay attention to the elephants' calls.

He expertly found the motorcycle helmet to put on, and hurried out for breakfast. Originally, there was no need to wear a motorcycle helmet today, even if the pointed ears were covered under the hair, no one paid attention to them, only to blame him for having to pull his ears.

Su Ji walked to several breakfast shops...... Now this point should be the home of those lunch and dinner restaurants, and after leaving the image of loyal customers and big stomachs for each boss, they have just finished tending to cucumbers and cherry turnips, and heard the cries of elephants.

Not only that, but these elephants are calling endlessly, once in a while.

Those elephant cries don't actually affect his work and life, as long as he doesn't understand the reason, why he can hear those sounds is very annoying.

Knock Knock Knock –

The knock on the door suddenly sounded, and then the sound of pushing the door sounded, and it turned out that Xia Houyue ran over from school at noon.

"I'll come over to see how your ears are......" She found that Su Ji was rare not to sit in the study reading books and playing with computers, but to stand in front of the floor-to-ceiling windows in the living room and look around, "What are you doing?" ”

Su Ji turned his head to look at Xiahou Yue and complained: "It's all your fault for talking about the zoo, which caused me to hallucinate and hear elephants crying from time to time...... Here we go again, every few minutes, every ten minutes. ”

He stood in front of the floor-to-ceiling windows of his living room to find the source of the elephant's call.

"What does it matter to me ...... listening hallucinations" Xiahou Yue said unconvinced, "What else are the auditory hallucinations, it should be where to put a documentary about elephants upstairs and downstairs." ”

"I made it carefully." "The elephant cries are coming from not upstairs or downstairs, but outside the window. Although it is said that it came from outside the window, it did not come from other buildings, but from a distance between the two buildings. ”

"Besides, documentaries can't just be elephants. Then I heard the elephant bark. He continued, "I don't know the source, I can only hallucinate." ”

"Is it possible that this elephant's cry is real, coming from the zoo." Xia Houyue's mind opened, "You have good hearing now, and you can hear the elephant cry from the zoo." ”

"Do you know how far our neighborhood is from the zoo?" Su Ji asked rhetorically.

"A straight-line distance of up to five kilometers." Xiahou Yue said affirmatively.

"Please, is five kilometers short?"

"It's long for us, not long for you."

"Even if my hearing was good now, I don't think I could hear an elephant five kilometers away." Su Ji said, "The main thing is that sound is sound waves, which will attenuate, unlike light that can travel no matter how far away. No matter how good my hearing is, it's useless to face the attenuating sound waves from five kilometers away. ”

"Hmm......" Xiahou Yue was speechless.

Su Ji frowned, thoughtful.

He had always thought he was hallucinating, and now he was a little skeptical that the elephant call was from the real elephants at the zoo.

"Check it, I'm going to check it." Su Ji said and went to the study.

He's looking for elephants.

He remembered reading an article about elephants before, and there was information about him in that popular science.

Su Ji quickly found the information he was looking for.

The data shows that elephants are very intelligent, they have a super memory, and at the same time they are very rich in language, in addition to the calls that can be heard clearly, smells, body movements, and infrasound waves that cannot be heard by humans, are all elephants talking......

Elephants generally transmit information through sounds, smells, limbs, etc., which are their unique languages.

Elephants communicate over long distances by emitting low-frequency sounds, also known as infrasound. When they are looking for each other, they transmit signals through infrasound waves. Or if they find something delicious at a distance from their companions, they will also use infrasound to inform each other, just like a "phone call" between humans.

Suji found the key word - infrasound.

"I know what's going on." He said, "Why do I hear elephants barking? ”

"How?" Xiahou Yue asked.

"The elephant is the largest animal on land, but it doesn't sound like a loud one...... This is wrong. Su Ji said, "In fact, the elephant's cry is very loud, but it emits infrasound waves, and the vibration frequency is not within the range of ordinary people's ears, and ordinary people can't hear its sound." ”

"But I can hear infrasound, so I can hear the elephant bark." He smiled, it turned out that the reason was so simple.

Xiahou Yue blinked his eyes and said, "Didn't you say that the sound wave will attenuate just now, how can you hear it again, or is there something wrong with the infrasound." ”

"Sister, have you almost forgotten your high school knowledge?" Su Ji complained, "Infrasonic waves are not easy to attenuate and are not easily absorbed by water and air. Infrasound waves, on the other hand, tend to have a very long wavelength, so they can continue to propagate around certain large obstacles. ”

He paused and said, "That's why I can still hear elephants here." Infrasound waves are very difficult to attenuate, they can travel here, and I can hear infrasound waves again."

"I see." Xia Houyue nodded, but her eyes were very clear.

Su Ji hesitated a little again, and said, "I'm still a little unsure, is there a way to try if I can hear infrasound." ”

To verify this, he wanted to do experiments.

It's just that as soon as this thought arises, he immediately becomes stupid, he doesn't know what can emit infrasound.

"Do you know anything that emits infrasound?" Su Ji asked Xiahou Yue.

"Yes." Without waiting for Su Ji to be pleased, Xiahou Yue spoke, "Elephant, elephant call." ”

Su Ji raised his hand and said expressionlessly: "A fist with a sandbag." ”

"We can't beat people at every turn." Xia Houyue smiled cheekily, "Check it on the Internet." ”

Su Ji decided to check it out online.

In nature, storms at sea, volcanic eruptions, large meteorite landings, tsunamis, lightning and thunder can all be accompanied by infrasonic waves. In human activities, such as nuclear explosions, missile flights, artillery launches, and the shaking of tall buildings and bridges, infrasound waves can be generated at the same time as sounds.

Seeing this, Su Ji's expression was a little distorted.

"What do you think of here?" Xiahou Yue suddenly patted Su Ji's shoulder excitedly.

Su Ji looked at the place where Xia Houyue's finger was on the computer screen-

Infrasound waves can interfere with the normal function of the human nervous system and endanger human health. Infrasonic waves of a certain intensity can make people dizzy, nauseous, vomiting, and so on. Some people believe that motion sickness and seasickness are caused by the infrasound waves associated with the operation of the car and boat. Stronger infrasound waves can also cause deafness, coma, insanity, and even death.

It is said that the tiger's roar is accompanied by infrasound, which can cause the resonance of the prey's internal organs, which can lead to endocrine disorders in the prey, produce a strong feeling of discomfort, and lose a certain ability to move.

"You said that your low roar can make people's blood cold and incapacitated, is it the reason for infrasound?" Xia Houyue said.

"Possibly."

Before Su Ji could open his mouth, he heard Xiahou Yue shouting and reminding, "Don't try here." ”

Su Ji couldn't shut up, he was uncomfortable.

"Here, look here." Xia Houyue said, "Here we talk about the application of infrasound. ”

She read it out.

"Natural disasters emit infrasound waves, and if you can hear them, you can predict disasters in advance."

"Not only are humans and other living beings capable of producing certain responses to infrasound waves, but organs also emit faint infrasound waves. Therefore, the properties of these infrasound waves can be measured to understand the activity of the corresponding organs of the human body or other living organisms. ”

Su Ji licked his tongue, his ability to hear infrasound seemed to have a great future.

(End of chapter)