When lechon Is served, the crispy skin is the first to disappear. How can one have pigs with abundant skin?
The answer may be found in the ratio of the area of the surface of a sphere to its volume, which is proportional to 1/r, where r is the radius. The smaller the r, the greater the ratio.
It can be shown that two small pigs have more skin than one big pig, where the volume of the big pig is equal to the volume of the two small pigs. Assuming that the pigs have a spherical shape for easy calculation, it turns out that the area of the skin of two small pigs is equal to the cube root of 2 times the area of the skin of the big pig. The cube root of 2 is more than one. For more skin, one should have more small pigs. If the number of small pigs is N, the total area of the skin of the N pigs is cube root of N times the area of the skin of the big pig. In the limiting case, the very small pigs are all skin.
It is the size that matters. We can see this in other examples. Food that is ground well before it is swallowed is easier to digest. Tube ice cools water faster than solid cubes. Shaved ice cools water faster than tube ice.
The smaller the particles, the more surface available for physical and chemical reactions. This explains the exciting properties of nano particles. Nano particles are those whose size is in a few nanometers, where one nanometer is one billionth of a meter.
A nanometer is used to measure things that are very small. Atoms and molecules, the smallest pieces of everything around us, are measured in nanometers. The naked eye can see objects that are 5000 nm width. However, a water molecule is less than one nanometer. A typical germ is about 1,000 nanometers. A helium atom is 0.1 nm. The wavelength of light in the visible spectrum varies from 400 to 800 nm. A hair strand is 50,000 nm wide.
A lot of important things happen at the nanometer scale. We can smell freshly baked cookies because the molecules released from freshly baked cookies are a few nanometers is size. Gravity does not have much effect on them and they float to the inner recesses of our noses to stimulate the olfactory senses.
Carbon ground to particles the size of sand has the properties of carbon. Ground to the size of flour, it still has the properties of carbon. Ground to particles that can no longer be seen by the naked eye, it still has properties of carbon. But ground to nano particles, the properties of carbon change. The smaller the size, the more different it is from the carbon we know.
In effect, just by decreasing the size of the particles we can have, as it were, new elements; Element with different chemical and physical properties.
This is the basis for nano technology. We are still in the realm of atomic physics, not sub-atomic or nuclear physics. Some discoveries in this new realm include paper-thin bullet proof vests, instant steam, more efficient solar cells, more efficient drug delivery systems, higher density hard drives, nano antennae, thin film lenses, and protein engineering, to name a few.