Have you ever heard that "people who are trained in muscles don't float in the water?"The muscles are heavy and the fat is light, so it is difficult for people with a lot of muscles to float in water.
Conversely, people with a lot of fat float in water.Then, somewhere, there should be a "borderline that just floats or sinks in the water".
The criterion for measuring the high fat is "body fat percentage", which refers to the ratio of fat weight to the overall weight.What is the body fat percentage that does not float or sink in water?
What kind of phenomenon is "floating in water" in the first place?
The object in the water receives "buoyancy" for the weight of the volume of the volume (the principle of alkimedes).For example, when a 1L volume box is sinked in water, the box works with 1 kg (= 1L of water) buoyancy.
If this box itself is 0.If it is 8kg, 0.0 with 8kg of gravity and 1kg buoyancy.The power of 2 kg works in the direction of floating in the water and floats.
Regarding buoyancy, it is often explained that "objects with smaller density float in water", which is also correct.The comparison of "water density x volume of objects" and "mass of objects" is the same as "water density" and "object mass / volume of object = object density".
Let's get back when we know buoyancy.Whether the body sinks or floats depends on whether the body density is larger or smaller than water.
The value of the density of the human body is well known, and the density of body fat is 0..9g/cm3, density of muscles and bones other than body fat 1.1g/cm^3.If you use this value and body fat percentage, the density of the body is
0.9 × Body fat percentage + 1.1x (1 body fat percentage)
Is required.
The density of the body is water density (1).The body fat percentage that is equal to 0g/cm^3) is 50 %.Therefore, people with a body fat percentage larger than 50 % float in water!Really ...?
The 50 % body fat percentage is obesity at a pathological level.It seems strange that it doesn't come to the water unless you are such a person, but is the calculation wrong?
If you are good at swimming, you will know, but if you dive in the water while sucking as a breath, it will gradually sink when you continue to exhale underwater.
The density of the body varies depending on the amount of air in the lungs, and most people sink in water if they are exhaled, but they usually float in water because they are inhaled.This is the identity of the discomfort in the line where the body fat percentage is 50 %.
The Dead Sea on the border between Jordan and Israel is famous as a lake with a high salt concentration and a body floating.You can calculate the reason why your body floats in the Dead Sea, so let's try it.
The average salt concentration of the dead sea is 25 %.The salt contained in the 1L of the Dead Sea water is 330g when calculated.The weight of the salt water is 1330g per 1L (together with the weight of 1L of water), so the density is 1.33g/cm^3.
The specific gravity of muscles and bones is 1.Because it was 1g/cm^3, even Mukimiki superhuman with a body fat percentage of 0 % would float in the dead sea.It's an amazing world where no matter how much you exhale.
If you have a chance to go to the pool, it would be interesting to try again to sink while exhaling.If you adjust it well, you may find an exquisite amount of breath without floating or sinking.
The fat is light and the muscles are heavy!? How different is it?: Close -up from Tanita
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