This young man dressed as a man is none other than Lord Longjun of today's Dragon City.

Since Qin Yunfei started to lecture in Dragon City, she has heard every day that there is suddenly an additional teacher in this Dragon City, who knows astronomy and geography, can resist wind and thunder.

And it just so happened that Qin Yunfei promised to explain organic chemistry to herself, but she didn't come for several days, so she disguised herself and planned to see if this teacher in the throne was the same Qin Yunfei.

After coming here, I found that the students in the entire Dragon City, whether it was the Star Soul Academy or the students of the Divine Machine Academy, actually came here to listen to the lectures.

In this way, she sat down with her, and when she saw Qin Yunfei lecturing, she looked at Qin Yunfei from a distance.

Its seriousness is that it is almost necessary to see any of Qin Yunfei's movements clearly.

At this time, Qin Yunfei talked about the change in the electron valence when the iron rod replaces copper ions, and he was in the hall and was making a demonstration.

This Dragon Monarch raised his jade hand and asked, "Senior Qin, I want to ask." If this galvanic battery is manufactured, can it replace the use of the Thunder Star Soul Crystal?"

Seeing Long Jun raise his hand to ask, Qin Yunfei wiped the cold sweat from his forehead and said in his heart, "Grandma, are you here to dismantle the stage?" But don't worry, I will never let you succeed!"

Although he was unwilling in his heart, Qin Yunfei was generous.

"This classmate asked well, in fact, the galvanic battery as a replacement for the thunder star soul crystal, in principle, is completely feasible. However, even if you know this principle, if you want to make a real battery, it still needs to be difficult. ”

Long Jun sneered, "In that case, then why should we study this? Wouldn't it be better to go to the Warcraft Forest and kill the Thunder Demonic Beasts to use them as backups?"

Long Jun's statement, although a bit overbearing, is also deeply popular.

Those students exclaimed, "Although it is a bit overbearing, it is exactly so." Since this galvanic battery is useless to learn, why don't we go and catch the thunder beast?"

"That's it!"

When everyone was amazed, Long Jun looked at Qin Yunfei proudly, obviously, this was the first trouble she found for Qin Yunfei.

But in the face of this trouble, Qin Yunfei did not panic, he sighed calmly.

"This classmate, I'll ask you a question first, and then let's talk about this replacement question, okay?"

Long Jun said confidently, "You ask, I'll listen." ”

At this time, Qin Yunfei asked faintly, "Classmate, let me ask you, how many square miles is the head of this Warcraft Forest?"

Long Jun said with a smile, "From the center of the Warcraft Forest to the edge, there is a total radius of 100,000 li. ”

Qin Yunfei sighed, "Yes, it's only four hundred square miles. Combined, it's only 40 billion square miles. Of course, this is still calculated according to the square, and if it is calculated according to the circle longitude, its size will be reduced. Of course, for the sake of calculation convenience, let's use these 40 billion to calculate, okay?"

Long Jun was taken aback by the data he said, so he nodded, "You continue." ”

In this way, Qin Yunfei continued to calculate.

"The habitat of this demonic beast actually has a certain rule, every square mile, there are about a hundred to a thousand demonic beasts, but among them, the demonic beasts that exceed the ten thousand grades must be at least more than a thousand square miles before they exist. Therefore, in this Demonic Beast Forest, there are only these 40 million Demonic Beasts that want to produce Star Soul Crystals. ”

Speaking of these 40 million, everyone was obviously surprised, they had never thought about how many demonic beasts there were in the Warcraft Forest and how many Star Soul Crystals could be produced.

But Qin Yunfei calculated it like this, and everyone had a new understanding.

But they hadn't been happy for long, but Qin Yunfei didn't stop there.

"But do you know? Among these ten million demonic beasts, there is not even one thousandth of them that have thunder star soul crystals. Therefore, if you want the Thunder Star Soul Crystal, the entire Warcraft Forest is only less than 10,000 heads. ”

As he spoke, Qin Yunfei suddenly looked at the desk and said fiercely, "However, our Longhua Empire has 80 million people! If you want everyone to be able to use electricity, how can you use 10,000 Star Soul Crystals to achieve the popularization of electricity?"

Qin Yunfei's last sentence was like an iron hammer, hammering the heart of this kind of person fiercely.

Even Long Jun had to keep his mouth shut and listen quietly to Qin Yunfei's explanation.

At this time, Qin Yunfei explained leisurely, "I want everyone to understand the primary battery, the reason is very simple, that is, so that everyone can brainstorm and achieve more battery production." In our Longhua Empire, why did people discover the light bulb very early on, but never promoted it? Is it because the light bulb is not bright enough? No! is it because there is not enough electricity!"

Saying that, Qin Yunfei shouted bitterly, "Because, those 10,000 Star Soul Crystals are far from meeting the needs of our lives!

After Qin Yunfei finished speaking, he took out the battery he made from his own ring.

"Actually, I have been researching the principle of galvanic batteries for a long time. Even, I have already manufactured a finished battery. But if I give this to you, do you know how to make it? It's not just a Star Soul Crystal, just press it in. Instead, we need to use our brains to realize their eternal power!"

After that, Qin Yunfei connected the light bulb to the battery, and the battery lit up, shining brightly, and it was very exciting.

However, even so, Long Jun had a little more admiration for Qin Yunfei, but she still looked at Qin Yunfei and asked leisurely, "According to your battery principle, ion power will run out sooner or later, so how can we achieve power storage?"

Qin Yunfei smiled slightly, "Water can go down from upstream, and we can naturally move water from downstream to upstream." In this way, it is possible to store electricity. ”

Long Jun sneered, "In that case, why don't we produce a battery anymore?"

Qin Yunfei smiled faintly, "What you said, that's a dry battery, not a battery." Batteries are the key to the development of science and technology, and they are not comparable to dry batteries at all. ”

As he spoke, Qin Yunfei drew a model of the generator boiler on the blackboard.

"In fact, if we want to store electricity, we only need to build a large boiler and then set up a large high-voltage generator set to achieve civil electricity!"

As soon as Qin Yunfei said this, everyone, including Long Jun, was stunned.

"What is this thing?" the students asked in horror, because they hadn't even heard of it.

At this time, Qin Yunfei said leisurely, "Open your basic physics, take a look at page 170, where is the principle of electromagnetic induction written?"