Is there a more beautiful topic than one more creative?

An unforgettable disturbance of the Imperial Fudo class.

Since I stepped through the doors of primary school, I have taken a lot of classes, including lively Chinese lessons, interesting math lessons, and mystical nature lessons. One of the third-grade nature lessons is still fresh in my memory and still remembers it vividly.

It was a Tuesday morning three years ago, near the end of school, and Ms. Hong gave us a special homework assignment, which was to prepare two eggshells for each person to go home. Hearing the teacher's assignment, we were all stunned, and some guessed that maybe the teacher was going to let us use it for handicraft; Some guessed that maybe the teacher was going to let us draw easter eggs; I guess Mr. Hong must let us do the experiment.

Looking at our puzzled looks, Mr. Hong showed a "mysterious" smile, as if to say: "The mystery of the next class will naturally be revealed." After class, everyone was anxious for Mr. Hong to quickly uncover the mystery, Mr. Hong guessed our minds and said slowly

Students, please put the eggshell on the table, we are going to use the eggshell for an experiment. "I was so surprised to hear that I was going to do an experiment, and I guessed Mr. Hong's intention.

Students, do you think this eggshell, is it the arched side that is easy to break or the concave side that is slow to carry it? ”

The students said in unison: "The sunken side is easy to break."

Why? "People don't know why.

Teacher Hong continued, "Please take out the eggshells you have prepared, and let's do an experiment together." ”

I put the eggshell on the ground with the arch side facing up, raised the pen in my hand and placed it at a height of about 5 cm on the eggshell, and with a gentle release, the pen hit the eggshell. Alas! The eggshell was unharmed.

I thought: Maybe I'm not doing it! Let's try again.

This time, I simply aimed the tip of my pen directly at the arch of the eggshell and killed it hard. Strange eggshells are still intact. I looked around, and my classmates looked puzzled just like me.

Seeing our blank appearance, Mr. Hong smiled and said, "Students will test the concave surface of the eggshell again, and then compare the differences." ”

We turn the eggshell upside down, so that the sunken side of the eggshell is facing up, and with a light stroke of the pen, the eggshell breaks. It turns out that the sunken surface of the eggshell is so vulnerable.

Teacher, why is that? Some of the students got tired of it and started asking questions of the teacher.

Mr. Hong picked up an eggshell on the table of the students in the front row and said, "This is the principle of thin shell structure, because the arched surface of this structure can counteract the action of external forces, the structure is stronger. The Great Hall of the People in Beijing and the Sydney Opera House have made full use of this principle, and of course, the principle of thin shells is everywhere in our daily lives.

Invite students to discover and excavate. ”

Over the years, I have also slowly discovered hard hats, windshields of cars, ......It all comes from the principle of thin shell, and Mr. Hong's class left me with a lot to think about.