Been to the beach? Gone into the water? Have you had the experience of going into the surf, playing around for 15 or 20 minutes, and then finding yourself a small distance from where you entered the water? What happened?
Typically, waves, which are generated by winds blowing across the ocean, refract or bend as they approach a beach. The bending isn’t always complete, but the appearance is that the waves approach the shore perpendicularly. In fact, there’s usually a slight angle. That angle is noticeable when you stand on the beach and watch the end of the wave, the swash, roll up onto the beach at an angle. It’s also visible when you watch the waves break right to left or left to right. It is this lateral break that enables surfers to ride waves.
The incomplete refraction of the waves moves beach sands and any object or person in the surf in a longshore current. The movement is called the longshore transport, and it’s highly effective because it moves hundreds of thousands of cubic meters of sediment along the Eastern Seaboard every year, and along some coasts around the world, it can move a million cubic meters per year. The sand you stand on at the beach one year is not the sand you stand on the next year.
Intellectually, we also find ourselves moving imperceptibly in a kind of longshore transport. Ideas come at us all the time. We pay attention to some, pay “half attention” to others, and pay no attention to the rest.. Those waves that catch only “half” our attention and those that we think we ignore work to move us without our knowing.
So, watch the polls. Should marijuana be legal? The longshore transport has shifted opinion. Should we fight foreign wars? The longshore transport has shifted opinion. Should we go into deeper debt? Should we abandon fossil fuels? Should we this, or that, or …
Imperceptibly, we move with the longshore current. We think we know where we entered the water, but after having immersed ourselves in the waves, we look up to find we are down beach from our entrance point. And we didn’t even know we were moving.
Typically, waves, which are generated by winds blowing across the ocean, refract or bend as they approach a beach. The bending isn’t always complete, but the appearance is that the waves approach the shore perpendicularly. In fact, there’s usually a slight angle. That angle is noticeable when you stand on the beach and watch the end of the wave, the swash, roll up onto the beach at an angle. It’s also visible when you watch the waves break right to left or left to right. It is this lateral break that enables surfers to ride waves.
The incomplete refraction of the waves moves beach sands and any object or person in the surf in a longshore current. The movement is called the longshore transport, and it’s highly effective because it moves hundreds of thousands of cubic meters of sediment along the Eastern Seaboard every year, and along some coasts around the world, it can move a million cubic meters per year. The sand you stand on at the beach one year is not the sand you stand on the next year.
Intellectually, we also find ourselves moving imperceptibly in a kind of longshore transport. Ideas come at us all the time. We pay attention to some, pay “half attention” to others, and pay no attention to the rest.. Those waves that catch only “half” our attention and those that we think we ignore work to move us without our knowing.
So, watch the polls. Should marijuana be legal? The longshore transport has shifted opinion. Should we fight foreign wars? The longshore transport has shifted opinion. Should we go into deeper debt? Should we abandon fossil fuels? Should we this, or that, or …
Imperceptibly, we move with the longshore current. We think we know where we entered the water, but after having immersed ourselves in the waves, we look up to find we are down beach from our entrance point. And we didn’t even know we were moving.
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