Physical Properties of Colored Parts

17.7.2002
Israel Fried

Physical Properties of Colors

Introduction

This article is prepared for this site. The aim of this article is to discuss the meaning of the physical properties that I am using along my new theory BioColorPhysics.

I wish to open this article by a remarkable example. For many years I am looking for a reasonable physical explanation to the Red color on the crown of the bird family Woodpecker. I see this bird pecking on the trunks and branches of trees in the woods near my house, foraging for insects under the barks and inside splits in the tree. I have many examples of other animals and plants where the Red color hints about the mechanical and thermal properties "Bending Elasticity" and "Heat Expansion" (see also in Table 1 at the next INTERNET page). But how those physical properties are explained in the case of the Red color on the crown of the Woodpecker in those woods. It is clear to me that if the bird is at hot temperatures, or exposed long periods to the sun, one may expect a Black color on the crown, as we see for example in the Hooded Crow (Corvus corone cornix). I regard the Black color as a hint to the mechanical and thermal properties: "Tension Stiffness" and "Heat Insulation". If, however the temperature is low, one may expect a White color on the crown, as we see for example in the gull of a kind Great Black-back gull (Larus marinus) that lives in cold sea cliffs. I regard the White color as a hint to the following mechanical and thermal properties: "Crush Elasticity" and "Cold Insulation". On the other hand, if the temperature is medium, i.e. not too high and not too low, one may expect the Gray colors. This color hints about the compositions of the physical properties of Black and White, in proportional parts. However, Red color in the woodpecker's crown was totally unexpected. I was trying to think of a mechanical mechanism that connects the pecking with "Bending Elasticity" of the crown. But there I could not find a good explanation. The thermal physical property connected to Red, "Heat Expansion" was even harder to explain. Therefore, I have not mention this bird in my articles so far. This issue was a mystery for me during many years

Fortunately, the mystery was resolved at the last days when I was looking for popular books in English about Nature (for including the common English names in this site) and I found in the public library an old book: "The Encyclopedia of Natural History", edited by Joyce Pope and introduced by the famous biologist Gerald Durrell, Octopus Books Ltd. , 1978. On page 198 of that book there is a schematic figure that explains the special way of the woodpecker to reach the insects form within the deep holes in the tree. Let me quote directly from that page:

"The woodpecker's tongue has a cartilage skeleton with two long horns, each extending round the head and sheathed in muscle. When the muscle contracts, these horns shoot out, extending the tongue".

Well, how all this resolves the mystery around the Red color on the crown of the Woodpecker?

The outside tongue becomes longer when the inside part of the tongue is shortened. What is the exact process for shortening. The single tongue is connected to two long horns made of cartilage skeleton. Each of these horns is sheathed with muscle. We have here the principle of a pair of parallel muscles that works in accordance, as much as in many groups of muscles in animal body. In Fig. 1 I draw a schematic sketch of the Woodpecker's head, as far as I understand the subject. When one of the muscle of the pair is contracted, the second is released. In order to return the situation, the second muscle should be contracted. Thus, the elongation and shortening of the tongue is controlled by massive activities of the muscles at the Woodpecker's crown, just below the scalp.

The contraction and releasing of those muscles may bend the skin of the scalp. After each bending, the skin should return to its normal situation. This is needed for the other functions of the skin. Thus, The skin of the scalp should have the additional physical property "Bending Elasticity". So, we understand now the mechanical property connected with the Red color on the crown of the Woodpecker.

What about the thermal property that connected to Red color, "Heat Expansion"? It is reasonable that when the Woodpecker feels the insects that sit deeply inside a split of a tree, it should act very quickly to get them on his tongue, before they escape into dark places due to the sudden light coming in - as a result of the removing of the bark by the Woodpecker. Thus, the muscle that elongated the tongue should be contracted very quickly. After the tongue reached some insect, it should be returned quickly into the woodpecker's mouth. Otherwise, the insect may run away or even harm the tongue. Thus, the second muscle, that shortens the tongue, must be contracted very quickly as well. Therefore, those two muscles, under the scalp skin of the Woodpecker, are contracted and release in very short times. As we know, muscle activity extract heat. In normal cases, the heat extracted by the muscle is absorbed by the surrounding of the muscle, and eventually goes out of the animal through the skin with a sweat, or it is used for other needs within the animal. But here, the extracting of the heat from the muscles bellow the scalp skin of the Woodpecker is so high, and at very short times, that the usual ways for getting rid of the heat are not enough. Absorption of too much heat into the head of the bird is out of question. Waiting until the usual amounts of sweat will emerge from the skin, might be too slow. A nice solution might be to expand the skin more than at normal activity, so that heat will radiate outside, alone or by greater amount of sweat. Expanding of the skin means expanding of the suit on it. Thus, the additional thermal property is "Heat Expansion". This is the second physical property we was looking for, in order to explain the Red color on the crown of the Woodpecker. Thus, we resolve the mystery around the Red color on the Woodpecker's crown.

In this example I have also demonstrated the main principles of the new theory BioColorPhysics, that I mentioned in the former Internet page. Let me try to answer the questions posted there, for the case of the Woodpecker.

a) What are the first important supplied needs of that specific biological item?

Answer to a) regarding the food. Special insects which are used to live inside splits of trees.

b) What are the obstacles standing in front of that biological item while trying to achieve those first important supplied needs ?

Answer to b) Hard barks of the trees.

c) What are the ways to overcome those obstacles ?

Answer to c) Pecking on the barks with the beak and make holes in the bark by rotating the beak, like a screw.

d) What are the ways for processing, conservation and emitting surpluses of parts of those first important supplied needs ?

Answer to d) Probably, the usual ways of birds. A research may show whether there are special ways here, due to the special diet: insects - from inside the splits of trees.

e) What are the structures and materials in the biological item for achieving all those ways ?

Answer to e) The beak should be long enough, but not too long, so that the act of pecking will be effective. The tongue should be able to be elongated and shortened back at short times. The other parts of the body should be adapted to climbing and pecking on trees. (I will not go here into all the structures, since they are mentioned in many places. I will concentrate here about some parts of the head).

The beak should be built from materials that are easy and strong, Keratin (??), as much as in all the birds' beaks. However, There are additional materials needed in the beak of the Woodpecker in order to supply the special physical properties of this bird, as discussed in the next answer.

f) What are the physical properties of those structures and materials?

Answer to f) In addition to the usual functions of the bird's beak, for Woodpecker the beak should have the following mechanical properties: "Torsion Elasticity" and "Shearing Stiffness". The "Torsion Elasticity" is needed for enabling the beak to act slightly like a screw, and return to the normal position after the torsion is accomplished. The "Shearing Stiffness" is needed in order to prevent broken of the beak when the beak is inside an hard bark and the bird tries to move the bark aside, in order to uncover the insects bellow the bark. By this act, there are developed two opposite forces on the beak, at the point near the surface of the bark. Thus, there is an act of shearing, as physicists call it.

g) How those structures and materials determine the shapes and colors of that specific biological item?

Answer to g) There is needed a deep research in order to determine exactly of what structures and materials built each of the parts in the Woodpecker bird. However, due to my observational research since 1984 I believe I have found most of the elements in a one-to-one correspondence between a set of Colors and set of Physical Properties. In Table 1, on the next INTERNET page, I give a one-to one correspondence between a set of 10 Basic Colors and a set of 10 Mechanical Properties. In addition I give there a one-to-one correspondence between those 10 Colors and between 10 Thermal Properties. I also see a one-to-one correspondence between the set of Mechanical Properties and the set of Thermal Properties. The meaning of "one-to-one correspondence" here is that to each color I correspond one physical property, so that each specific color hints about a specific physical property and vise versa, each physical property hints about the expected color.

In the case of the Woodpecker I have shown how I find a true physical property by seeing the Red color on the crown of this bird. Now, with regard to the functions of the beak of this bird, we saw in the former answer that there are expected, in the beak, additional mechanical properties: "Torsion Elasticity" and "Shearing Stiffness". From Table 1 we see that the Blue color is corresponded with the "Torsion Elasticity" property and the Yellow color is corresponded with the "Shearing Stiffness" property. Thus, there should be combination of Blue and Yellow. Let us suppose for this argumentation that the combination is 50-50%, although this is a subject for a future research. In this case, the color we get for the beak is Green. Having this conclusion I took at hand the Hebrew translation, from 1975/6, of a bird's guide: "The Birds of Britain and Europe with North Africa and the Middle East", H. Heinzel, R. Fitter and J. Parslow, 1972. There I found that most of the kinds of birds in the family of Woodpeckers (Picidea) have red crowns and yellow beaks. More over, those colors, with regards to the crown and the beak, are very rare among the birds in that guide.

h ) What are the chemical processes for achieving those physical properties ?

Answer to h) I am not a chemistry, nor a biologist and I do not now what are the chemical processes for achieving the physical properties associated with the Red color on the Woodpecker's crown, "Bending Elasticity" and "Heat Expansion". Since the Red color in birds appears much less than the Black, White and Gray colors, it is reasonable that there are needed special materials for producing Red.

i ) What are the biological processes for achieving those chemical and physical properties?

Answer to i) Biological researchers may give the answer in the future. I may only note here that I expect specific biological processes for achieving the Red color, since the Red color is not so usual among the birds.

j ) How does that specific biological item uses its specific physical, chemical and biological properties for achieving secondary purposes?

Answer to j) We saw that the Red color hints about specific physical properties. These are the main purposes of the animal. But, now that it has the specific Red color on his crown, the Woodpecker may use it for secondary purposes. People may say that the Red color is a warning sign for predators, to tell them that its taste is not so good. I myself do not know whether it is tasty or not. As we know, there is no accounting for tastes. There are predators that would be very happy with the taste of the Woodpecker. After all there is unwritten low in Nature: If there is something to eat, there will be found the one who will eat it. On the other side, there might be predators that are used to the taste of, say, a Sparrow bird, but not the taste of the Woodpecker. The specific chemical matters and the biological processes that are needed to get the physical properties which associated with Red color, might repulse this predator. It might be used to tastes of less special materials. For instance, those that are associated with the Gray color - the Color of the Sparrow. After all, to create special colors you need special materials. Thus, even if the Red color causes to bad taste for some predators, it does not mean that the Woodpecker have painted (along the Evolution) its crown with Red color for this purpose.

Additional Notes:

Note 1. In that bird guide's book of Europe, North Africa and the Middle East, I see there are differences in the length of the Red color stains on the heads of different kinds of Woodpeckers. If my above explanation is true, the kinds with shorter stains may mean shorter muscles bellow the scalps that controls the elongation of the tongue. The amount of elongation may depend on the depth of the usual splits in the trees where the specific kind of Woodpecker forage for insects. Thus, in different kinds of woods there are different kinds of Woodpeckers.

Note 2. In addition, the females of most of the Woodpeckers in that book are with no Red stain at all. This may hint that the functions of the females are different than those of the males. They are probably less active in foraging insects from within deep slits. They probably live on a diet of insects that are more exposed. On the branches or the ground. The male's function is probably to reach the most delicate insects, those from within the deep slits.

Note 3. With regards to the colors of the beaks. I see in that guide's book there is a one kind of woodpecker with a beak that its color is closer to Yellow than to Green. This is the big Black Woodpecker (Dryocopus martius). According to the explanation above, this may mean there is less Blue Color in the compositions of that beak color. As we saw above, the Blue color hints about the mechanical property: "Torsion Elasticity". Less Blue may mean less need for torsion of the beak. Thus, I may expect the Black Woodpecker to live on trees that their barks are not too hard, so there is less need for screw acts of the beak, in order to dig a hole in the tree. According to that guide's book, this bird lives in forests of needle and beech trees. It is known that those kinds of trees have soft pith. The needle trees have much lower bulk density than the hard-wide-leafs trees, such as an Oak tree. This is why they are used so widely in buildings. However, the big size of the Black Woodpecker, in relation to the other kinds in that book, hints that it is easier for him to dig big holes for nesting. The wide Red stain on his crown shows, in view of Note 2 above, that the slits might be very deep, so the tongue should be elongated, proportionally, much more than, say, the Syrian Woodpecker with a small Red stain on the male's nape. This last kind is probably the one I use to see on the Pecan wood in my neighborhood in Israel. Return to the Black Woodpecker, the bigger holes in the trees he lived on, may include bigger insects. Thus, the big size of this bird may hint in this case about the big size of its special food. This is not true for any animal. The whale, for example, lives on small biological items, but in enormous quantities. But in birds I think there is usually a correlation between the size of the food and the size of the bird.

Note 4. I said above that I see a on-to-one correspondence between the set of 10 basic Colors and the set of 10 mechanical properties, as well as between the Thermal properties. I was talking above about the Mechanical properties of the beaks of the Woodpeckers kinds, in accordance to their colors. But I have not mentioned the Thermal properties that one may extract from this one-to-one correspondence, with regards to the beaks. Due to this correspondence we may relate thermal properties to beaks. But, I immediately asked myself what thermal needs could be at all in the beaks. After short thinking it became clear to me that this subject may be of great importance. I don't know whether this subject is treated before by science. If not - let this note here open a new field for researchers. The following may show the importance of the thermal properties in bird's beaks.

Suppose the male of the Black Woodpecker brings to its female or young a fresh live insect that he just dug from a deep hole inside a far tree in a very cold day. Until he arrives to the nest, the insect may die and its taste may be less good. Therefore, keeping the insect by a beak that conserves heat may be useful in this case. In Table 1 we regard the Yellow color as corresponding to the thermal property "Heat Conservation". Thus, the Yellow color of the beak of that Black Woodpecker may hint about the function of the beak as a conservator of heat at cold places. Indeed, this bird lives in areas where there are needle trees. Needle trees grow usually in cold places. Thus, the importance of this thermal property in that beak seems to be clear. I wold remark here, by the way, that the Black color of the whole body of this Black Woodpecker hints that this bird is exposed to the sun most of his life. Since the sun arrives mainly to the top of the trees in those needle forests, I believe that this bird is living on the high branches of those trees. There the barks are softer and many insects may develop inside the relatively higher temperatures. This resembles to me the special epiphytes at the top of the rainy jungles, where the male of the Peacock finds it best food, as explained in my article "Physical Explanation to the "Eye" at the Peacock's Train". (This article is already included in this site). Here we are talking about cold forests, but there is the same principle connecting between the sun and the most delicious food.

So far we saw the Thermal property of the beak with regard to the Yellow color. What about the other main colors, blue and red. As we see in Table 1, the Thermal property associated with the Blue color is "Cold Contraction". How can such a property for the beak helps a bird with Blue beak. Suppose for example that the bird coming from a place with moderate temperature into a very cold area. A blue beak is vary rare. Of the hundreds kinds of birds of the 65 families in that Birds guide's book of Europe, North Africa and the Middle East, there are only less than about 10 kinds where the beak is blue or bluish. Most of those blue beak birds are from families of ducks in cold area. The most pronounced example is the White-headed duck (Oxyura leucocephala). The male has white forehead and faces. In the summer its beak becomes blue. This kind is used to swim while the whole body, except the head, is inside water. It is quiet reasonable that the change in the color of the beak at summer may help this duck to overcome the great difference in temperature of the beak between inside and outside of the water. Another pronounced kind is the Scaup (Aythya marila). This duck belongs to the Divers. It also has blue beak. It lives in lakes of fresh water in the Tundra and Taiga, i.e. at cold zones. If my speculation regarding the "Cold Contraction" is true, it might be interest to search how those two kinds of ducks uses this thermal property while they put their beak inside the water after it was exposed to sun. I just guess here that the beak of many ducks may expand due to the heat of the sun. For some ducks this expansion might disturb to open quickly the beak inside the somewhat denser water (due to the cold) and get thier food. Contraction somewhat of the beak may help them to overcome this obstacle. This speculation should be checked by biologists.

Many of the Woodpeckers in that guide's book have Green beak. This may hint that their beak has half levels of the following Thermal properties: "Heat Conservation" and "Cold Contraction".

Note 5. We see an important feature in that example, of the Woodpecker's Red stain on its head. The color may be due to inside influences, not only outside ones. If we see a stain of color on a part of an animal, we may look for physical reasons to that stain in all the things that may be in contact with that stain.

Here is a picture of a Woodpecker with small Red stain on his nape. The picture was taken from the free Galery of Tripod.