Explain the cause of human having 10 fingers

With 10 flexible fingers, we can grasp objects easily as well as perform many clever movements.

Mark Changizi, an American neuroscientist, developed a mathematical formula called the limb law (Limb Law) that could be used to explain the number of legs of an insect or other animals that Just rely on its leg length, according to Science 2.0.

People have 10 flexible fingers to handle objects.(Photo: Instructables).

According to the law of chi, the amount of organism (N) is calculated as follows: N≈2π / k. Let L be the length of the limb and R be the body radius, k be the chi ratio, k = L / (L + R). The shorter the length of the limbs, the more accurate the result.

Now we use the law of limbs for human hands to explain why the hand has 5 fingers. The hand is born to grasp, the length of the finger approximates the diameter of the palm. That is, the length of the finger is twice the radius of the palm.

Instead of the formula we get L ≈ 2R and k ≈ L / [L + (L / 2)] = 2/3. Then, applying the formula of the law of chi: N ≈ 2π / k, we obtain N ≈ 9,42.

This result shows that there are about 9.42 fingers growing from the perimeter of the palm. But we need to remember that the palm is not a free-living animal. The palm attached to the arm on nearly half of its circumference. The fingers can only grow from the other half of the circumference. Therefore, the number of fingers on the hand is 9.42 / 2 = 4.71 fingers. This result is rounded to 5 fingers.