'The Tides', or 'Things that are so much more complicated than they seem'

So, it's the middle of the summer. That time of year when TV stations play Christmas in July specials and the Earth decides it wants to try and set fire to anyone who walks outside by bombarding them with UV radiation. And what better way to celebrate this fact than going to the beach? 


The beach, as it turns out, is full of physics. In fact, the beach wouldn’t even be there without physics. It’s the motion of the tides that eroded the rocks that originally created the border between sea and land, turning everything into sand. And of course, what makes the tides come in and out? The gravitational pull of the moon. 

As romantic as it sounds, the pull of the moon on the sea is actually fascinating. At high tide, water is pulled towards the moon ever-so-slightly. This subsequently creates a low tide on the sides of the Earth, the places that the water is being drawn from. Yet, the opposite side of the Earth also has high tide, since the effect of the moon goes straight through the Earth! 

This MS Paint drawing just blew my mind. 

It’s a beautiful thing, the tide. Why, though, does it fluctuate so much in a given day? If it’s just the Moon circling around, what makes the water level change so much? You’ve probably guessed the answer: the Moon is not the only thing pulling. The Sun, as big as it is, also has a significant effect on our planet’s oceans. In fact, the two sometimes work in sync: when the Sun, Moon, and Earth are all aligned (also known as a 'syzygy' in astronomical terms) they create what is known as spring tide. When this happens, the high tides become higher, the lows become lower, and the sea gets a little wild. When storms happen during spring tide, they have the potential to do more damage, because they physically have more to build from. 


The opposite happens when the Sun and the Moon are angled against one another. When this happens, their effects almost cancel one another out, and a neap tide develops. This is the shallowest tide, where neither the high or low tides are that extreme. However, even with only two bodies pulling at the Earth, there's still a lot of variation. Here's a chart surveying the extremes of the tides across the world:

Tell me that makes sense. There's no pattern here at all; it just seems like a divine hand is picking places at random and messing with their water line. Yet, there is some strange sense to it all. This chart acts like a sort of topographical map for the tides, but not in the way you're used to. The areas where the lines meet, in blue, signify the places where the tide never really changes, the deepest parts of the ocean. From here, one can follow a line all the way up to the most severe tides, like those located on the shores of Alaska and Western Europe. This just illustrates how many forces are at work when the tides rise and fall: the Sun, the Moon, the depth of the water, and even the tilt of the Earth (notice Antarctica's unchanging tides). 


Crazy. Physics has a way of complicating things that seem so natural on the surface. But, like the tides illustrate, it's what's under the surface that really matters. That, and things that are really, really high above the surface. 

WORDPLAY!
...I tried. 

P.S. - For those of you who like to surf, you'll be happy to know that the tide level seems to have no effect on the height of the waves. These are actually caused by the wind on the surface of the ocean, and are more affected by the rotation of the Earth than anything else, through something called the Coriolis Effect. Wondering what that is...? 

Well, stay tuned.*

*That, or check Wikipedia. I'd go with the blog, though.