WHY DOES A FOOT BRIDGE feel more like footbridge when it tapers narrower at the center, springing larger from either end? 
 
Study your own feet when you step across a creek. Your right foot is planted on one bank. You pay attention to where you place that foot. You look across the creek and find the place your left foot will land, safely. You step across. The arching of your calves, then thighs dome at your groin and continue down the other leg to the ground. If a slow motion mental image could be produced of the action of your brain as you step-bridged the creek, I would predict that there is more electrochemical activity associated with the stepping off and the landing than the actual act of spanning. 
 
Thus, the footbridge FEELS better, fatter at the launch and the landing because it mimics what's going on in your brain. This is what I think but it's not science, yet.
 
But there's another reason and it is pure science. A simple bridge (meaning a bridge that spans a void in one simple movement) is a double-cantilever connected at the middle. The Moment of Inertia, the twisting force, is larger at the spring points, the anchors, the foundations where the assault against gravity begins and decreases as the span increases until, at the middle, it's possible to leave a hole. There is very little force in the middle of the span.

Look at the simple suspension arches of the GOLDEN GATE BRIDGE. The orange steel cables mimic perfectly the strength of the force of the span. Fat and high and thick at the column supports, the bank, lowering, thinning, dematerializing towards the center of each span.
 
We can prove how bridges should be built but bridges should feel like bridges too. Gather its power at its spring points and lighten its load as it jumps. The bridge will feel like it functions and it will function as it feels.

WHY DOES A PALAPA feel more like a place to sit and share when it's built in a circle of columns? 
 
How would it be to play Ring around the Rosy holding hands in a square? How would it feel to play Dodgeball in a rectangle? How would it feel to sit AT, instead of AROUND, a camp fire singing Kumbaya? 
 
The science of a circle is the geometry of enclosure. The circle radiates from a single point. The compass is placed on paper and the pencil is spun around. An infinite number of points form the circumference, Pi times twice the radius. The area, Pi times the radius squared. A changing of scales moves the point-circumference-ratio: the circle is an atom, is a Sunflower, is Dodgeball, is a camp fire, is theater in the round, is Earth circling Sun, is galaxy spiraling about our own black hole.

The magic of a circle is the geometry of enclosure. STONEHENGE is contained and magnified through standing stone megaliths along the circumference of a circle. The point of power in the CAPITOL OF THE UNITED STATES, is the center of the rotunda, is the center of a circle, a sphere, is the science of the circle, is the poetry of a circle.

WHY DOES A TOWER feel more like a tower when it emerges thicker at the base, growing thinner as it rises? 
 
Put the EIFFEL TOWER point first into the ground and you will have missed the point, entirely. You will have an upside down, pointless prank. All too often, award is given to an architecture that simply (and in most cases, grotesquely) is conceived to surprise, to offend, to trick, to cause into question.
 
A tower is the same science as a bridge only it stops at half span, springing up instead of over. It rises as a cantilever into the sky, from ground-bound foundations, where twisting forces, the Moment of Inertia, are greatest. It rises and steps back, lightens and dematerializes. It reaches into the void. These are the towers that FEEL like towers.

THE WIZARD'S TOWER feels like a castle. Castles are castles for reasons. 
 
We'll climb those walls of reason next week in THE DESIGN OF SCIENCE, 101.
 
We'll discover that buildings have feelings.
 
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