Friday, September 21, 2012

Rising to the Top


What lifts around 4 tons of water to a height of 300 feet every day, silently and without any moving parts?  This amazing feat is accomplished by the millions of tiny tubes called xylem, micrometers in diameter, in the trunk of the Giant Sequoia tree. Three natural processes combine to enable water (with nutrients) to reach the farthest reaches of these magnificent trees.

Capillary action: The cohesive properties of water make capillary action possible. The simple water molecule, H2O, happens to be electrically polarized, which means it acts like a tiny magnet. When a group of water molecules stick together, surface tension results. Surface tension is one reason rain drops form round shapes, or insects can glide over water. This polarity also helps water molecules adhere to certain surfaces, like glass. Conversely, water is repelled from other molecules like oil. Water in a thin glass tube hugs the interior glass surface and moves up the tube forming a meniscus.  This demonstrates what is called capillary action. The thinner the tube, the higher the water can rise. This is how water behaves in the xylem of the tree.

Adding to the strength of capillary action, trees along with all other plants are made up of cellulose, which is also polar. (Cellulose is made up of oxygen-hydrogen and hydroxyl chains. It is the hydrogen-bonding interactions between water and cellulose, with its hydroxyl side-chains  that provide an energetic gain against the gravity.) This allows the water to ‘hug’ the cellulosic part of the tree as the water climbs. In fact, trees are ‘masters of microfluids.’ The tiny tubes get narrower as the tree grows taller, allowing for water to continue climbing until its pressure decreases as it fights it own weight (gravity). This limits the height of the tree.

Two other processes contribute to the rise of water in the tree: evaporation in the leaves of the tree pulls the water up; osmosis in the roots of the tree pulls water and nutrients into the tree. All this is done without the tree making a sound or using any moving parts. In fact on a global scale, the movement of water through plants makes a major contribution to the hydrologic cycle by providing the particular pathway by which water moves from soil to the atmosphere (see Ref. below).

“Blessed is the man who trusts in the Lord. He will be like a tree planted by the water that sends out its roots by the stream.” (Jeremiah 17:7) Jesus said if we believe in him “streams of living water will flow from within.” (John 7:37)  The amazing process that occurs silently within trees, illustrates the power that is ours in Jesus Christ, as we allow the living water of his spirit to flow through us.
For more information see: ‘Transporting water to the tops of trees’ Physics Today, January 2008; Tree Physics 1: capillary action, the height of trees and the optimal placement of branches:/; and also Action.htm

Tuesday, September 18, 2012

The Stones Cry Out

Small portion of Last Supper mosaic in St. Isaac's Cathedral
During his final week on earth, Christ entered Jerusalem as a King - riding on a donkey! This graphic and unexpected entry enraged the ‘powers that be,’ particularly the religious leaders. Here was a man, a miracle-working man, who spoke with authority and had a large following, entering their territory, with humility and riding on a donkey. It was too much! They were beside themselves when the people bought into the narrative and shouted out, “Blessed is the King who comes in the name of the Lord.”  They urged Jesus to tell his followers to shut up! But Jesus replied, “If they keep quite, the stones will cry out.” How can an inanimate aggregate of minerals cry out? How can the ‘stones’ reflect God’s glory?

In 1985 we visited Russia, then under the sway of Marxist-Leninist atheistic philosophy. Most of the churches had either been closed, or were used for storage or as museums. One of the most beautiful churches in all of Russia, St. Isaac’s Cathedral in St. Petersburg, was open as a tourist attraction. A Foucault Pendulum had been hung from the highest point of its dome and the church was being used to show the superiority of science, the god of the Soviet Union. While foreign tourists stood in the center of the church, watching the swinging ball, local Russians stared at the cathedral’s walls. On its walls were the most exquisite mosaics I have ever seen, depicting scenes from the Bible. In those days, it was impossible to find a Bible in Soviet Russia, so this was the only ‘bible’ the people had. Like the religious leaders of Jesus’ time, the atheistic leaders of Soviet Russia miscalculated when trying to suppress God’s glory - and the stones were crying out. 
St. Isaac's Cathedral; painting by Surikov

Stones or ‘lithos’ (Greek) have two characteristics which make them wonderful symbols. First they are long-lasting, almost eternal when viewed from our short life span. Second, they are firm or steady and represent a solid foundation. Jesus told a story about a wise man who built his life on ‘the rock.’ Jesus is represented in the Bible as the ‘stone which the builders rejected,’ but those who build their life on him have an eternal, firm foundation and cannot be shaken. “I lay a stone in Zion, a tested stone, a precious cornerstone for a sure foundation; the one who trusts will never be dismayed.” Isaiah 28:16 

Thursday, September 13, 2012

Four Amazing Features of Feathers

Male Indian Peafowl (Courtesy of Creative Commons Attribution - Share Alike 2.5 Generic)

Field biologist Thor Hanson recently published a book on the nature and functions of bird feathers and their amazing structures. The four functions feathers perform and their complex structure are marvels of ingenuity that defy the most advanced human technologies, to such a degree that they clearly indicate a master designer.

The four primary functions identified by Thor Hanson are:
1-Insulation, protecting the fragile bodies of birds
2-Water proofing for birds that swim
3-Aerodynamic features to enable a smooth, energy conserving flight
4-Ornamental colors, for attracting mates (mostly males attracting females).

Feathers are made of fibrous proteins called keratin. As they start to grow they are connected to blood vessels over the skin of baby chicks for transporting nutrition and aiding growth. Once mature, they are disconnected from the blood source. The insulating properties of feathers are legendary. No wonder the warmest blankets are stuffed with feathers! When Hansen carefully plucked the feathers of a tiny, dead wren, he counted as many as 1500 feathers covering the body!

The waterproofing feature of a water-adapted bird, such as a duck, is just as marvelous. The water repellent function of these feathers is not only based on their oily-ness but is also a result of a unique structure. Even after washing the feather with a mild acid solution, it still retains its waterproof qualities.  As for the aerodynamic features of these feathers, it has been shown that each individual feather has the shape of an airfoil, the very engineering design that enables airplanes to fly! In fact, the wings of eagles have such an amazing aerodynamic design that the bird easily flies, even in turbulent weather.  Airplane pilots avoid such weather, but the eagle uses it to soar! The incredible variety of colors adorning a bird is itself a miracle to behold. The ultimate example of extravagance in color and beauty is the peacock.

Such a common thing as a feather declares the artistry and engineering genius of the Creator God. No wonder scripture uses the metaphor of feathers to express some of God’s most intimate care and protection of His children. “He will cover you with his feathers, and under his wings you will find refuge.” Psalm 91:4

Thor Hanson's book, Feathers: the Evolution of a Natural Miracle, can be found on Amazon.