Many times, we wonder how many people can be carried in a floating cabin? If I were a heavy person, wouldn't I be able to float? Or is it difficult to float?

Let's analyze the essence of this problem step by step, and you will understand.

Firstly, why can the human body float on top of the floating liquid but not sink? The answer is simple, because the floating liquid is a supersaturated mineral solution with a density generally ranging from 1.29g/cm ³ (the density of the Dead Sea ranges from 1.25g/cm ³ to 1.29g/cm ³), while the density of our human body is usually only 1.02 g/cm ³. Therefore, the human body can easily float on top of the floating liquid without sinking to the bottom.

After understanding this point, let's continue to look at the previous question: "If I am a heavy person, can I not float? Or can I not float very well?" Combining the principle of density, let's think from a different perspective. What you are worried about is whether you think that the larger the weight, the higher the density, which will affect the body's floating effect?

Alright, it seems that this question is now clear at a glance. The so-called density refers to the amount of mass contained in an object per unit volume, which is called density. The calculation formula is ρ=m/V, so density is only related to the two factors of mass and volume. Through the formula, we can know that the size of density is directly proportional to the mass of the object and inversely proportional to its volume. That is to say, the larger the mass, the higher the density, and the smaller the volume, the higher the density.

So the perplexing question arises: the mass of overweight individuals is clearly greater than that of thin individuals, but similarly, the volume of overweight individuals is also greater than that of thin individuals. According to the previous formula, the result is whether the density of overweight individuals is higher or that of thin individuals is higher?

Alright, let's not sell the key anymore, let's just release the answer! The answer is that fat people have a lower density, while thin people have a higher density.

Why is that? Firstly, we calculated an average density. The average density of a person is equivalent to that of liquid water at 4 degrees Celsius, slightly larger than 1g/cm3, but smaller than that of saline water. For the same adult, gaining weight increases mass m and volume v, making weight easy to weigh. There is no particularly good measurement method for volume except for drainage, and without data, it seems difficult to determine density changes. But in mathematics, for a positive or false fraction, increasing the upper and lower numerator and denominator by the same amount is decreasing. 

And assuming the original density was b/a (b>a>0), while the fat density was smaller than water, around 0.9, that is, the current density is b+n/a+m (0<n<m). Subtracting the two yields [bm an/a (a+m)]>0, (bm>an), which means that compared to thin people, the density of fat people has decreased. It's okay if you don't understand, you can look up more information.

In this way, let's return to the earliest topic of why people can float on floating liquid but not sink? The answer is that the density of the human body is lower than that of the floating liquid, with objects with higher density at the bottom and objects with lower density at the top. Now, let me ask you again, do you think fat people can float?