Ask A Scientist© General Science Archive

name         Victoria
status       student
age          12

Question -   Why are so many natural or man made things curvilinear  -
How come I don't see many straight edges in nature?
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Hello,

This is a very good question, and I do not think I can do justice to it in 
a short reply and without thinking more about it.  I share with you some 
ideas here.
First, the straight line is a very specific kind of a line and I do not 
think that it is particularly over- or under-represented in nature. In 
fact, if many of the "natural" lines were straight, we would then wonder why?
Secondly, we need to ask what we mean by a straight line. I assume you are 
referring to "visually" straight lines. In that case, your perception and 
perspective are also important.  The trunk of a tree may look straight to 
us at a distance but can be quite irregular as you look closer.

A more general and physical explanation for the shape and patterns in 
natural (and man-made) things could be given as follows.
The physical, structural, and functional attributes of natural things have 
evolved over time, over millions and billions of years, as a consequence of 
their interactions with their natural environment.
The outcome of these interactions, in most instances, is anything but 
random.  There are laws governing these interactions.  So, not only the 
shapes but also the properties and functions are determined by the 
governing laws.  So, to ask why something has a peculiar shape or function 
is asking, "what relevant laws govern its creation, evolution, and function?"
Laws of nature are peculiar and often elegant.  We can discover them but we 
have no clue why they are there. We can find "what and how" they are and 
not "why" they are.  Underlying many of these laws are others, such as the 
conservation laws.  These, to me at least, seem to be nature's clever way 
of managing itself.
In summary, we can say that things have the shapes they have because their 
existence and evolution, by necessity, follow certain laws that dictates 
those preferred shapes.  But we do not know why those laws are the way they 
are.

For example: Why are tree leaves mostly green? Why is the sky blue?  Why 
are the pebbles on the shore round? Why is raindrop round and not square? 
Why are soap bubbles round and not cubic? And so on.

The answer to these are, respectively, chlorophyll, light scattering, wear 
by collision and water action, and surface tension (for the last two.)  I 
am pointing to the governing laws to explain the shapes.  But in the final 
analysis, I can say how they are but not why.  The "why" question, I think, 
is not one that science can answer at this time. It is more of a 
philosophical and theological question and beyond my knowledge.

Good luck,

Dr. Ali Khounsary
Advanced Photon Source
Argonne National Laboratory
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Because there are a zillion ways to be crooked but only one way to be
straight.  Nature tries everything, so if you take random samples of
things Nature has tried, you get a straight line once every zillion
samples.  And you don't see precisely the same crookedness any more
frequently than you see straight lines.

However, if you look closely at crystals of pure substances (or of
precisely the right mixtures of the right different substances), you'll
see lots of straight edges.  Nature's not all that big on pure
substances, though, because there are a zillion ways to be mixed...

Tim Mooney
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Nature does have a lot of straight lines especially when discussing light 
direction and crystalline faces.  Slate is a rock that has straight lines due
to its crystalline structure.  However, most living things are made up of 
organic compounds that are polar (unsymmetrical if you like) in nature and do
not form "straight lines" in their compound bondings.  If Nature was inorganic 
(bonding in patterns to a degree), we'd probably see more "straight lines".

A chemist would complain like crazy to my above explanation!!  I have over 
simplified it all a bit!

Furthermore, organization takes energy and forming straight lines would be 
organization to a degree.  Man makes straight lines out of nature, but it 
takes energy to do so.  Nature is just plain lazy!

Steve Sample
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