Black tech dad

Chapter 151

"It's really cold in the imperial capital." Feng Hao walked into the school snack city, found his daughter's place, ordered food, and waited for it to be served.

"Father, the cold in the imperial capital is different from the cold in Canton." Feng Yuechan tilted her head playfully.

"What's different?" Feng Hao asked.

"The cold in the north is a physical attack, and the cold in the south is a magical attack." Feng Yuechan laughed, "Actually, it's because of your unscientific way of dressing."

"How do you say that?" Feng Hao looked at the way the students around him dressed, and asked in confusion, "Everyone wears a set of long johns and long johns on the inside, and a coat on the outside. If it's still cold, you can wear another one in the middle." sweater."

"Everyone wears clothes like this, but it doesn't mean it's a scientific way of dressing." Feng Yuechan said earnestly, "In ancient times in the West, before Copernicus' heliocentric theory, everyone believed in the earth-centered theory. The egg's worldview."

"Uh..." Feng Hao froze for a moment.

"What? Don't believe me? Let me prove it to you." Feng Yuechan was eager to try.

"This... can also be proved?" Feng Hao asked strangely.

"Yes, it can be proved. Mathematical modeling is a method of using mathematics to solve real problems." Feng Yuechan said solemnly, "Recently, I am preparing for the US emperor's digital modeling competition, so I have studied mathematical modeling. According to the mathematical modeling method of solving problems , you need to ask questions, choose methods, derive formulas, solve models, and answer questions.”

"But the eight words 'scientific way of dressing' can't be connected with mathematics at all." Feng Hao frowned.

"Who says you can't?" Feng Yuechan reminded, "You have to read the title several times. If you don't understand, read the title. If you don't understand, continue reading the title. Come and read it with me."

"The scientific way of getting dressed."

"The scientific way of getting dressed."

"The scientific way of getting dressed."

"..."

"understand?"

"I……"

🇧🇷
Feng Hao said that there was no way to connect.

Hey.

Feng Yuechan sighed: "If you don't understand the question, it's because you didn't think in the direction of mathematics. Come on, let me show you the process of solving the problem."

"First, assume that a person is a barrel. That is, a cylinder with a constant temperature of 37 degrees, a bottom radius of 20 centimeters, and a height of 175 centimeters."

"Then, let's assume again. Clothes can be seen as several layers of barrels wrapped around this barrel."

"Next, our question is, if you are given a autumn coat and a trench coat, which layer should you wear on the outside?"

Feng Yuechan stopped, looked at her father who said "ohhh", took out a pen and paper with a sense of accomplishment, drew a three-dimensional coordinate axis, and said.

"The bucket inside is you without clothes, the bucket outside you is you in autumn clothes, and the bucket outside is you in autumn clothes and a coat."

"understood."

Feng Hao suddenly realized.

Although it is not something esoteric, and it ignores the differences in height, stature, and sensitivity of different people, but the way of thinking that can realize abstract concepts into mathematical models is exquisite in itself.

Feng Yuechan continued: "The question has been raised, so let's use experiments and theories to find out which clothes should be worn outside."

"First of all, we intuitively experience the warmth retention effect of different clothes. The core that determines the warmth retention performance of a piece of clothing is the heat conductivity and thickness of the clothes."

"We wrapped the warm water bag with the initial temperature of about 54 degrees with the clothes, and measured how much the temperature of the clothes rose after 5 minutes."

5 minute later.

"In the same period of time, the autumn clothes rose to 44 degrees, which was almost close to the temperature of the hot water bag, while the windbreaker only rose by 10 degrees. It shows that the warmth retention effect of the windbreaker is far better than that of the autumn clothing. The next question should be the warmth effect It’s better to wear it outside or inside.”

"Here, we need to use the radial heat flow equation of the barrel wall below the ordinate to interpret..."

φ=（T0-T∞）/{[ln(R2/R1)]/2πLK1+[ln(R3/R2)]/2πLK2}
"The main component of autumn clothes and long johns is cotton, and the thermal conductivity K1=0.050W/mK. The main component of the windbreaker is wool and polyester fiber, and the thermal conductivity K2=0.029W/mK. Then measure the thickness of the clothes and bring them into the in the formula."

"If the jersey is worn inside and the windbreaker is worn outside, the radius R1 of the person is 200mm, R2 is the radius of the person plus the thickness of the autumn clothes, which is 203.42mm, and R3 is the thickness of the person plus the thickness of the autumn clothes and the thickness of the coat, which is 208.75mm , into the formula, it can be calculated that the heat dissipation is 330.5W."

"Similarly, if the jersey is worn on the outside and the windbreaker is worn on the inside, the heat dissipation will be 328.8W."

"see it?"

(⊙ o ⊙) Ah!
What to look at?
Feng Hao was stunned.

I don't know what to look at.

Feng Yuechan shook her head: "If you wear a coat under your jersey, your cooling power will drop by two full watts, what does that mean, do you understand?"

(⊙ o ⊙) Ah!
not understand.

Feng Hao was dumbfounded.

I don't know what to understand.

Feng Yuechan sighed: "If you wear autumn clothes outside and stand outside for two full days, you can save the calories of an entire egg."

(⊙ o ⊙) Ah!
Dad said he couldn't keep up with this mathematical thinking.

"Forget it, I'll show you the temperature distribution diagrams in the two situations again, it's clear at a glance."

As soon as the words fell, the holograms of the two chapters appeared in front of my eyes.

The temperature distribution map of autumn clothes inside and windbreakers outside (author’s note: can’t be displayed, can only be dictated, the temperature of readers in the cylinder is red to represent the hottest, red spreads outward, and gradually turns into yellow with low temperature, but the whole The red spreads through the thickness of the jersey and spreads to the surface of the windbreaker. Then it gradually fades to a cooler blue in the windbreaker.)
The temperature distribution map of the autumn clothes outside and the windbreaker inside (author's note: cannot be displayed, can only be dictated, representing the hottest red is bound on the contact surface of the windbreaker and readers)
"Through the temperature map, you will find that wearing autumn clothes outside and windbreakers inside will firmly bind the temperature around your body, so this is a more scientific way to wear."

"So, if you are afraid of the cold when you go out in the future, wear autumn clothes outside to keep warm scientifically!"

○|￣|_
"It's really a choice between demeanor and temperature or temperature and demeanor. It's a difficult problem in life." Feng Hao smiled wryly, "I finally understand a problem that has troubled me for a long time."

"What's the question?" Feng Yuechan asked curiously.

"Why does Superman wear underwear outside?" Feng Hao said with a serious face.

puff-

(*^__^*) Hee hee...

Feng Yuechan laughed so hard that she felt inexplicably happy seeing her dad deflated, and suddenly thought of something, and asked, "Dad, I haven't been back for a month, are the pandas taking care of you?"

"Don't worry, the panda is fine." Feng Hao said casually, "I found a breeder for it, who is very professional, and guarantees that it will enjoy unique care."

(End of this chapter)