Don't brag! Because bragging is really hard...

The poem says:

Why is the sky so dark?

Because cows fly in the sky.

Why are cows flying in the sky?

Because people are blowing on the ground!

Source: Yearbook of the 21st anniversary graduation reunion of a certain class in the 21st century.

Bragging (also known as bragging, bragging B) has become a common idiom in our daily life.

The word "boasting" is often used to describe exaggerated and unrealistic statements. So, where did the word "boasting" come from? Why do people brag about their own strengths? What interesting stories and scientific principles are behind it? Today, let's unveil the mystery of "boasting" and find out from ancient wisdom to modern jokes.

1. The Origin of Bragging: Ancient Wisdom and Challenges

Since ancient times, there are two main theories about the origin of the idiom "bragging".

1. River crossing tool: the birth of the raft

The word "吹牛皮" originated in the upper reaches of the Yellow River in my country and is related to the means of crossing the river. In ancient times when bridges and transportation were not well developed, people living along the upper reaches of the Yellow River faced the problem of river crossing and transportation. The Yellow River was turbulent and difficult to sail, so the working people came up with a brilliant solution: using rafts instead of boats.

They peeled off the entire fur of cattle and sheep, dehaired them with salt water, and then applied vegetable oil to the limbs and neck. They then soaked the fur in water and exposed it to the sun to make it soft. After that, they used thin ropes to sew the treated fur into a bag shape, leaving only a small hole for blowing air. After blowing enough air, the small hole was sealed tightly. Multiple leather bags were fixed under the raft to make a leather raft that could carry thousands of pounds of weight (Figure 1).

Figure 1 The ancient wisdom of rafting

This kind of raft, also known as "leather boat" in ancient times, is named because it is made of sheepskin or cowhide. It not only solves the problem of river crossing, but also becomes the most distinctive traditional tool for people along the Yellow River.

The ability to brag has become an important skill in making rafts.

2. Butcher's Challenge: The Difficulty of Bragging

However, the term "blow up the skin" has another origin related to butchers. When butchers slaughtered livestock, in order to make it easier to skin them, they would first cut a small hole near the hoof of the livestock, then blow hard until the whole body of the livestock swelled up (Figure 2). In this way, the livestock would be blown up so that the skin and fur could be shaved cleanly, which would also make it very convenient to skin them.

Figure 2: When slaughtering an animal, air is blown into the animal's skin through the hoof. Of course, different parts of the animal are blown, and there are different ways to say "blowing xx".

This method is relatively easy for smaller livestock such as pigs and sheep, but it is almost impossible to accomplish for large cows with tough skin. To inflate the entire cow, one must have a very large lung capacity, which is simply impossible for ordinary people. Therefore, if someone boasts that he can blow up a cow, it is equivalent to bragging and exaggerating.

In this way, the meaning of "bragging and boasting" is extended.

2. The biomechanical mechanism that makes bragging more difficult

We have already learned the origin of "boasting", so why is it more difficult to brag than to brag about other things? This requires us to analyze it from the perspective of biomechanics.

As a biological tissue material, cowhide has unique mechanical properties, which determine that greater resistance needs to be overcome when bragging, making it more difficult to brag.

Compared with sheepskin, pigskin, fox skin, etc., the biomechanical properties of cowhide are significantly different in many aspects. These differences are not only reflected in the physical properties of the material, but also directly affect the difficulty of bragging about it. The following will compare the biomechanical properties of these leathers in detail from multiple angles, and use scientific research data to explain why it is more difficult to brag about it.

1. Thickness and density

Cowhide is much thicker than sheepskin and fox skin, and has a high density and a tight texture. This structure makes the cowhide more stable when subjected to external forces, but it also increases the difficulty of blowing the cowhide. In contrast, sheepskin and fox skin are thinner and less dense, so they are more likely to deform when blown.

2. Tensile strength and toughness

Tensile strength looks at the maximum amount of tension a material can withstand, just like the maximum amount of tension a rope can withstand.

Toughness focuses on the ability of a material to absorb energy, deform without breaking, and recover to a certain extent when subjected to external forces, just as plasticine can resist external forces and recover its shape better than crackers.

The tensile strength of cowhide can reach tens of megapascals (MPa), while the tensile strength of sheepskin and fox skin is relatively low. The tensile strength of cowhide is significantly higher than that of sheepskin, pigskin, fox skin, donkey skin and horse skin. This means that when blowing cowhide, greater resistance needs to be overcome to deform it. At the same time, cowhide is also extremely tough and not easy to stretch and break, which further increases the difficulty of blowing cowhide. In contrast, sheepskin and fox skin are more likely to deform when blown because of their lower tensile strength and better toughness.

3. Elastic modulus and deformation capacity

The modulus of elasticity describes the "stiffness" of a material, or how well it resists elastic deformation. The larger the modulus of elasticity, the harder it is to stretch or compress the material. You can think of it like the "hardness" of a spring. If it snaps back to its original shape quickly when you compress or stretch it, then the spring is "hard" and has a large modulus of elasticity. If it snaps back to its original shape slowly or deforms more, then the spring is "soft" and has a small modulus of elasticity.

Deformability describes the ability of a material to deform without breaking when subjected to an external force. Materials with high deformability usually have good toughness and ductility. Let's go back to the spring example. If you stretch the soft spring with a lot of force, it may deform a lot without breaking. This shows that the soft spring has good deformability. On the contrary, if the hard spring is stretched too much by the tension, it may suddenly break.

Cowhide has a larger elastic modulus and is more resistant to deformation. When blowing cowhide, a larger air pressure is required to cause it to deform significantly. However, sheepskin, pigskin, and fox skin have a smaller elastic modulus and are more likely to deform, so the pressure required for blowing is relatively small.

4. Stress-strain curve

The stress-strain curve describes the deformation behavior of a material under stress. In professional terms, the stress-strain relationship is the constitutive relationship of the material, which is a core issue in biomechanics. If you are interested, please refer to my personal WeChat public account "Medical Biomechanics" article: Two Core Issues in Biomechanics.

The stress-strain curve of cowhide shows a high initial elastic modulus at the initial stage of stretching, that is, the slope of the stress-strain curve is large (Figure 3), which means that a large air pressure is required to overcome its ability to resist deformation at the initial stage of bragging. As the tensile strain increases, the stress of the cowhide will also increase rapidly, further increasing the difficulty of bragging.

In contrast, the stress-strain curves of pigskin, sheepskin, and fox skin rise more slowly in the initial stage of stretching, showing a lower initial elastic modulus, that is, the slope of the stress-strain curve is smaller (Figure 3). This means that the air pressure required in the initial stage of blowing these leathers is lower, but as the deformation increases, the stress will gradually increase. However, in general, the force required to blow these leathers is still less than that of blowing cowhide (Figure 3).

Figure 3 Comparison of stress-strain curves of different types of animal leather

3. Fun and jokes about bragging: from ancient times to modern times

The term "boasting" not only has a profound historical background and scientific principles, but has also become a joke and topic of conversation in people's daily lives. From ancient times to the present, there are endless anecdotes and jokes about boasting.

In ancient times, some places would hold a competition for blowing cowhide. Participants would use their mouths to blow up a balloon or a part of a raft made of cowhide. Whoever could blow the biggest or farthest in the shortest time would win. These competitions not only tested the participants' lung capacity and blowing skills, but also became a topic of conversation and jokes for people after dinner.

In modern times, the word "boasting" has evolved into an adjective to describe exaggerated and unrealistic statements. In daily life, we often hear such jokes and jokes as "You are bragging again!" and "You are really good at bragging."

Some people tend to exaggerate their achievements, wealth or experiences to attract attention and praise. However, these exaggerated claims often cannot withstand scrutiny and verification, and will eventually become a joke after dinner.

IV. Conclusion: The wisdom and lessons of bragging

Although the word "boasting" has a certain derogatory connotation, it also contains the wisdom of ancient people and the jokes of modern society. By understanding the origin and biomechanical mechanism of "boasting", we can have a deeper understanding of the scientific principles and historical culture behind this word.

At the same time, "boasting" also brings us some lessons and enlightenment. Mount Tai is not built by stacking, and bragging is not blown. In life, we should maintain an honest and humble attitude and not exaggerate or brag about ourselves unrealistically. Only in this way can we win the respect and trust of others and become a trustworthy and respected person.

In short, the word "boasting" not only has a profound historical background and scientific principles, but has also become a joke and topic of conversation in people's daily lives.

Bragging is tax-free, so it is a waste if you don’t brag. Finally, it is time to brag (Figure 4). I learned biomechanics today, so I will have more money to brag tomorrow!

Figure 4: Bragging rights

The word "boasting" not only has rich historical and cultural connotations, but also contains profound biomechanical scientific principles. From ancient wisdom to modern jokes, "boasting" has always accompanied our lives and has become a unique cultural phenomenon. This article allows you to learn some interesting scientific knowledge and life wisdom about "boasting" in a relaxed and pleasant atmosphere.