Monday, August 3, 2009

Wave Theory

I think I finally understand how waves in the ocean are kinetic energy. I knew they were, of course, because all energy moves in waves, but I think I am only understanding now what I wanted to know when I was a kid: why waves get bigger as they move towards shore, and why they take the shape they do when they break.

Most waves are caused by wind, and wind is air pressure (air moving from an area of higher pressure to an area of lower pressure). This pressure presses on the deep water out in the ocean. Just like the wind on land comes in gusts, on the water it is also intermittent and each "push" causes waves.

The energy on this scale must be massive! This energy is distributed deep into the water (think of hydraulics: any pressure on part of an enclosed fluid is distributed so that you have the same pressure at all points. The ocean isn't enclosed, of course, but the wind pressure happens over such a wide area that there is a similar effect.) All that energy moves in a wave through the deep water, and since it is a large amount of energy in a large quantity of water, the wave at the top is small. As it nears land, the water the wave is moving though gets shallower and shallower, but you have (more or less) the same amount of energy moving through it.

The breakthrough thought for me was this: the wave is not the water, the wave is the energy moving through the water.

All that energy has to go somewhere, of course, and the wave tries to hold it's shape. When I see a wave rising up out of the ocean, I'm seeing the deep wave coming ashore holding onto as much water as it can in a fight against gravity. The wave breaks when gravity wins and dissipates that energy.

And where did that energy come from? The sun! Most wind (changes in air pressure) comes from the sun heating the atmosphere. When watching the waves, I am seeing transformed solar energy!

Thinking this all through gave me a new perspective on Creation: looking at waves on the ocean, I am seeing energy moving in the universe in a nearly raw form. It's amazing! It's like looking at God's fingerprints.

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