Shadow of great britain

Everyone's eyes were focused on the podium, and everyone wanted to see what kind of results could make the usually calm and collected Mr. Michael Faraday so happy.

Faraday smiled and said: "I believe many of the listeners here know that the world's research on electricity and magnetism has actually been carried out for many years.

But in the earliest days, scientific researchers believed that these were two independent and separate disciplines.

But businessmen disagree with us.

Because in the 18th century, a London businessman made an astonishing discovery that his box of iron spoons became surprisingly magnetic after being struck by lightning.

This disagreement between scientific researchers and businessmen was not resolved until 1820, when Danish scientist Hans Oersted conducted an experiment.

He placed the wire parallel to a magnetic needle, and when he turned on the current, he was surprised to find that the magnetic needle actually jumped.

After repeated experiments, Oster confirmed that this was not a coincidence. Soon, he published a paper titled "On the Current Impact Experiment of Magnetic Needles." The scientific community called this great discovery the "magnetic effect of electric current."

From then on, we shallow scientific researchers finally realized that electricity can produce magnetism.

When I turned to the field of electrical research at the behest of my mentor Humphry Davy, my first thought was - if electricity can produce magnetism, can magnetism produce electricity?

For this conjecture, I have conducted countless experiments over the years, and finally, not long ago, I finally got an amazing answer.

Electric energy produces magnetism, and magnetism can indeed produce electricity. Electricity and magnetism are not independent subjects, but unified subjects with strong correlation! "

After saying this, Faraday removed the black cloth covering the experimental table.

What is displayed in front of everyone is a six-inch round iron ring densely wrapped with white cloth. The left and right halves of the ring are wrapped with two strands of insulated copper wire.

The left half of copper wire connects a set of handmade batteries to form a separate set of circuits.

The right half of the copper wire is only connected to an ammeter.

Faraday enthusiastically introduced to everyone: "As you can see, these two sets of circuits are independent and not connected. We call the circuit on the left with a battery A, and the circuit on the right without a battery but connected The current meter is called B.

Therefore, according to our common sense, even if circuit A is powered on, the ammeter pointer of circuit B will not deflect.

But is this really the case? "

Faraday walked forward with a smile, and he gently turned on the switch of circuit A.

Under the gaze of everyone, everyone present discovered that the ammeter of circuit B actually deflected slightly in the clockwise direction, but soon returned to its original position.

When Faraday turned off the switch, the ammeter actually deflected in the counterclockwise direction.

"OMG!"

"How is this going?"

Someone exclaimed: "Mr. Faraday, isn't this really because you shook the table?"

Faraday said humorously: "Although the Royal Society has always lacked funds, we are not so poor that we cannot afford a suitable experimental table. If you don't believe it, you can try it yourself. Starting now, my hands Get off the table.”

He invited the gentleman who had just raised the question to the stage. The gentleman tried seven or eight times and carefully inspected the experimental table before he exclaimed.

"Although I know that every lecture you give is very exciting, this one is undoubtedly the best ever! Please allow me, on behalf of the audience here, to pay you my highest respect again."

After saying this, the gentleman took off his hat, put one hand on his chest and bowed slightly.

The audience once again burst into prolonged applause.

At this moment, another man stood up in the lecture hall.

He questioned: "Mr. Faraday, although I don't mean to offend. But I wonder if the iron ring you used in your experiment is leaking electricity?

After all, both circuits are connected to the iron ring. Although you have insulated it with white cloth, there may still be current flowing along the iron ring. "

When Faraday heard this question, he did not answer directly, but smiled and said: "In that case, please look at the second experiment."

After saying this, he uncovered the black cloth on another experimental table.

The experimental device this time was much simpler, with only an ammeter, a hollow coil wrapped with copper wire, and two sections of copper wire connecting the two.

Faraday took out a magnet from his trouser pocket and put it into the hollow coil.

The magnet flashed past, passed through the coil and landed on the table. At the same time, the ammeter also deflected.

Faraday smiled and said: "Sir, you saw it. This time, I didn't even use the battery."

The audience present all exclaimed: "Oh God! This may be the biggest discovery of the year!"

"Mr. Faraday, by combining electricity and magnetism into one, you may be able to rival Sir Isaac Newton in this achievement."

Faraday just nodded slightly in return for the audience's support, with a bright smile on his face. Although he was happy to have his academic achievements recognized, he still did not forget his mission.

Conducting experiments is only the first step. The most important thing is to gain experience through experiments and summarize it into a conclusion that can be repeatedly verified, and explain the reasons and analysis process for this phenomenon.

Elder in the audience saw Faraday's magic-like experiments, and heard him talking about terms such as magnetic field lines. He felt dizzy and couldn't understand anything.

He elbowed Arthur beside him and asked in a low voice: "Do you understand?"

Arthur raised his eyebrows and winked at him: "I understand a little bit. To be honest, this is actually the second time I've heard it."

"Ah? Have you secretly come to attend lectures before? Why didn't you tell me?

Forget it, tell me about those messy magnetic field lines, and how to distinguish the direction of the current and the direction of the magnetic field.

This thing is too difficult. I finally attended a lecture and had to learn a little bit. Otherwise, I won’t know what to say when I chat with those beautiful ladies who like science in the future. "

Arthur said: "Let me teach you an easy way to remember."

Elder asked curiously: "What easy way?"

Arthur said: "If you want to distinguish the direction of the current, then stretch out your right hand. Put the four fingers together and keep the thumb perpendicular to the other four fingers.

Yes, that's it, all five fingers remain on the same plane.

Next, align the palm of your hand in the direction of the N pole of the magnetic field, and align your thumb in the direction of the conductor's movement, which is the direction in which the magnet will fall.

Then, the pointing of your remaining four fingers is the direction in which the induced current is generated. "

After hearing this, Elder said in surprise: "Arthur! You are such a genius! How did you come up with this method?"

Arthur avoided answering this: "Do you still want to learn how to judge the direction of force on a conductor?"

"Learn, of course I want to learn!"

"Then shut up and stretch out your left hand."

"Oh? I switched to my left hand again this time?"

"Don't talk so much nonsense, just listen to me..."

Unexpectedly, before Arthur finished speaking, a gentle questioning voice suddenly sounded in his ears.

"Excuse me, what are you talking about?"

Arthur turned around and saw that Faraday had walked up to him and Elder at some point. The two ordinary boys suddenly became the center of attention.

Faraday smiled kindly and said: "Mr. Police Officer, can you tell me about the right hand again? I only heard half of the right hand. As for the left hand, we can talk about it later."