Dorp and Sam cornered the tip of Florida and were riding the Gulf Stream up the East Coast in the Atlantic Ocean. 

The Gulf Stream goes up the East Coast quite a way. 

Being water, Sam and Dorp had nothing but time; no bills, no homework, no clothes, no cupcakes; nothing but time. 

Sam commented, “The water sure moves around a lot. I see waves and tides and the water is, er, we are moving along, having no propulsion system. If nothing we can see is pushing it, there must be a lot of energy coming from somewhere.”

“Very good, Sam. We are in the Atlantic Ocean. The energy that moves us is from solar heat, wind currents, gravity and even fish swimming through the water. But mostly, we are moved about by tides caused by solar, earth and lunar gravity. 

So then, the sun is the source of a lot of the energy that is moving us around. “ 

It’s like turning a glass of iced tea in your hand. Though the ice cubes don’t move the same speed as the glass, they still move. The water in large areas move along a set of currents known as a gyre, which we talked about earlier.” 

“Is that like a gyro? Boy, I love the taste of gyros...the meat in the pita bread. Wow.” 

“Sam, both words are rooted in the Greek word gyra, which means circle. It is also the source of the name for the instrument called the gyroscope.” 

“Mr. Dorp; there are more waves here than on the Mississippi River. Why is that?” 

“Excellent question. Waves are a sign of a disturbance in the water. “Think about the creek at your grandparents’ acreage. 

In the north pasture, the land gradually meets the waterline like a beach, but without the sand. While in the west timber, 

the creek passes through a deep ravine, where you can’t walk to the water without falling and rolling into the creek.” 

“I know that! How do you know that? Have you been there too?” 

Dorp nodded 'Yes' and continued, “Seas and oceans have the same kind of shorelines under the water. Where the bank under the water drops away gradually, you’ll see small waves as the tides ebb and flow. But if the underwater bank gets really deep in a hurry, the incoming tides will bring tall, powerful waves. Even if you can’t see underwater, often you can read the lay of the underwater terrain by watching the waves. 

“Like a secret code, eh? I have a joke. What is a sailor’s favorite jelly?” “I don’t know Sam. What is it?” “Current (currant) jelly. HA! Hey; I’ve read the words ‘ebb and flow’ in a poem about the sea. What does this mean?”

“Clever joke. 'Ebb and flow' means to retreat and advance, like the tides. Back to the discussion at hand. The gyres I spoke of earlier are large ocean currents. This gyre we’re in now is called the North Atlantic Gyre. It begins at the equator, and like all gyres in the Northern hemisphere, it moves in a clockwise direction, like the hands on a clock. The North Atlantic Gyre brings warmer water from the equator, through the Caribbean, with some of it passing through the Gulf of Mexico. This is why we are here now. It bends around the coast of Florida and follows the eastern coast of the US.” 

“All the way to Canada?” asked Sam. 

“Sorry; it doesn’t quite make it to Canada. It veers to the right at Virginia, due to the shape of the coast and because of currents moving south from the Labradorean Drift from the North. The North Atlantic Gyre circles around, coming down the coast of Western Europe and then to Northwest Africa. Do you ever wonder why the east coast of the US is so green, while Western Africa is so dry? 

“Sure ... I guess?” 

Reader, ocean gyres are a big part of the answer. Warm ocean currents catch and release more moisture than cooler ocean currents. The North Atlantic Gyre brings warm water up the east coast of the US from the equator. The moist air above the gyre is pushed inland where it is available for precipitation. It then cycles east bring moisture to Western Europe before it cools from and hits northwest Africa. This part of Africa doesn’t get much moisture. The Northern Pacific Gyre first moves up the Southeast coast of Asia, where it dumps lots of rain, called monsoons, before it crosses over to Alaska and Canada, then cooling down at the Oregon/California border, leaving southern California and western Mexico high and dry.