Tuesday, March 25, 2008
Disaster in the Making
Little Joe, our first-born grandson
came running in the house.
While playing in the cellar,
he had seen a mouse.
Straight to the back bedroom he came,
and the rifle in the closet.
The four-year-old is cute and quick;
his mind goes lickety-split.
I grabbed the gun, and away he went
to the kitchen for a knife,
determined he would win the war,
a little Barney Fife.
How did he know the gun was there -
in a corner, almost hid?
What might have happened if I wasn’t near?
Disaster! God forbid!
With five of our own and eight grandkids,
this wasn’t the only close call.
We lived on a roller coaster,
an adventure over-all.
Cora Gail Trent
www.cgtrent.com
cgtrent@att.net
Monday, March 24, 2008
Follow the Leader
the first time they went to the field alone.
A thankless job is hoeing, plodding on with thirst and sunburn,
your legs becoming achey to the bone.
I spied the small blue pickup swirling dust as it came homeward,
the hoeing crew all loaded in the bed.
Had a hoe cut off a dirty toe, a snake bite caused disaster?
A million questions whirled within my head.
I ran out back to meet them as they hurried up the driveway,
the portent in the air foretelling doom.
What happened? Who was injured? Is there anybody dying?
No, Molly only has to use the bathroom!
Cora Gail Trent
www.cgtrent.com
cgtrent@att.net
Monday, March 03, 2008
Leaves
Most of us, in the Midwest at least, take trees for granted. They are so common and seem to grow so easily that we fail to consider how carefully they have to be designed to survive. The leaves of trees are especially complex. Not only is their chemistry that turns sunlight and common chemicals into usable complex compounds highly sophisticated, but their physical makeup and shape are also carefully engineered.
Leaves have to be arranged on a tree so that there is an efficient interception of the sun’s rays. If you have ever stood beneath a tree and looked at its shadow, you know that very little sunlight is wasted.
In addition to absorbing sunlight and carrying on photosynthesis, leaves have to be able to endure a great deal of physical abuse. In severe wind, a leaf has to have minimal drag. If the drag of leaves is high, a tree will be toppled by even moderate winds. To have a low drag, the shape is critical. A highly streamlined object with a gentle rounding upstream and an elongated point going downstream will experience less than 10% of the drag of a sphere or a cylinder of equal volume. The complex shapes of most leaves do not conform to this simple shape we have just described.
Steven Vogel, writing in Natural History magazine (September, 1993, pages 59-62), has found that when exposed to wind, leaves reconfigure themselves into cones or roll themselves up so that they are stable in high winds. It is obvious that a rolled-up leaf or a cone-shaped object is less likely to catch wind than an open object which can act like a sail. Groups of leaves can naturally fold into a communal cone, once again minimizing the drag that they put on the tree.
There are enormous engineering problems involved in catching maximum sunlight, having enough volume to carry on sufficient photosynthesis to supply the needs of the plant, and having a way to avoid providing sufficient surface area to push over the tree. The design of leaves that allows all of these characteristics to be present is incredible. A leaf’s stem must resist bending in an up/down direction in order to catch sunlight. To provide the rolling up of leaves or the formation of cones, the stem must permit twisting. This is done by grooves in the stem which are positioned in such a way as to decrease torsional stiffness without decreasing flexural stiffness.
The common leaf speaks eloquently of the incredible complexity of all living things. We suggest that the assumption that chance can explain all of these things takes more faith than does the admission that intelligent design was the cause.
—John Clayton, Dandy Designs, September/October, 1996
Cora Gail Trent
www.cgtrent.com
cgtrent@att.net
