Monday, December 25, 2006

88)Snowflakes, a beautiful, symmetric 'ayat'(sign) in creation and one of its marvels.

The seat of sequential, discursive intellect discussed in my last post(no. 87), the human brain, is what allows us to carry out logical, rational experiments on one of Allah's prettiest signs('ayats') in nature, the formation of snowflakes. In an interview to Spiegel magazine in October 2006, Mowlana Hazar Imam said the following about the religion of Islam:

"Of the Abrahamic faiths, Islam is probably the one that places the greatest emphasis on knowledge. The purpose is to understand God's creation, and therefore it is a faith which is eminently logical. Islam is a faith of reason."

My thoughts on the full extent of "God's creation" are outlined in post number 62 of this blogsite.

The subject of snowflakes is a fitting one for those of us who live in the Northern hemisphere at this time of the year:

Atmospheric science

Fake flakes

Dec 19th 2006
From The Economist print edition

A sprinkling of labs around the world are trying to grow snow crystals

THERE is something about snowflakes that scientists cannot leave alone. Johannes Kepler, the man who worked out the orbits of the planets, wrote a book about them as a new-year present for his patron. Robert Hooke, Isaac Newton's low-born rival who came up with insights about gravity that Newton may have stolen, first applied the microscope to them. And RenĂ© Descartes once wrote, “So perfectly formed in hexagons, and of which the six sides were so straight, and the six angles so equal, that it is impossible for men to make anything so exact.” But in this as in so many things, Descartes was wrong. For John Hallett of the Desert Research Institute in, appropriately, Nevada, is really rather good at making snowflakes.

Dr Hallett is one of a small band of latter-day snowflake researchers. He makes his flakes in a chamber that mimics the swirling balance between wind and gravity in which natural snowflakes form. He then compares flakes grown in these controlled conditions with natural flakes, and is able to infer what was going on in the places where those natural flakes formed.

The details are surprisingly complicated. Experiments done in the 1930s by Ukichiro Nakaya, a Japanese scientist, showed that whether snow forms in the flat and flowery shapes that grace Christmas cards, or as hexagonal prisms that look like cross sections through pencils, depends on the temperature. The six-petalled ice flowers grow in air warmer than -3°C. Between -3°C and -10°C, prisms form. Between -10°C and -22°C, it is ice flowers again, and below that, prisms once more.

Dr Hallett is building on Nakaya's work to look at how such things as humidity affect the process. It may sound esoteric, but he hopes that understanding the conditions needed for particular sorts of flake to form will enable meteorologists to give out accurate warnings of air-pockets that pilots should avoid in order to prevent their aircraft icing up. And if that were not practical enough, others are looking at the role snowflakes have in catalysing the transformation of ozone into normal oxygen.

Ozone is a version of oxygen with three atoms per molecule, whereas normal, everyday oxygen has only two. At ground level ozone is a dangerous pollutant, but at altitude it blocks the passage of harmful ultraviolet light. Understanding the role of snowflakes in catalysing the change from one sort of oxygen to the other should provide insights into how ozone is distributed in the atmosphere.

Another way of growing snowflakes is to use an electric field. This is the approach employed by Ken Libbrecht, of the California Institute of Technology. Starting with a small piece of frost on an electrode, he has grown ice stars and flowery stalks of impressive beauty. The method works because the electrical field polarises the electric charge on water molecules in the air around the icy tip and then draws them in electrostatically. At about 1,000 volts this effect races away—the more pointed the tip, the stronger the field becomes, and as more water molecules attach themselves to it, the tip becomes more pointed.

Unlike Dr Hallett's convection-grown snowflakes, Dr Libbrecht's electrically generated crystals have no obvious applications. Sadly, they do not even offer much insight into thunderstorm snow. But they do demonstrate the importance of unstable conditions in imparting to snowflakes their famous diversity.

Exact mathematical explanations of this diversity are some way off, but people are working on them. Jon Nelson, of Ritsumeikan University, in Japan, has calculated that the most important property involved is the surface tension of the tiny clusters of water molecules from which snowflakes form. This can vary in non-obvious ways as temperature alters. That variation, he believes, dictates the way snow crystals grow. His model predicts that these clusters will change size at the temperatures at which newly forming snow alters from flower mode to prism mode, and vice versa. And, yes, this, and the instability that Dr Libbrecht demonstrates, is probably sufficient to make every snowflake different.


Islam, eminently logical, placing the greatest emphasis on knowledge, purports to understand God's creation:Aga Khan 4.
The God of the Quran is the One whose Ayats(Signs) are the Universe in which we live, move and have our being:Aga Khan 3