Tides will get bigger over the next 10 million years

This week's New Scientist has an article "Tides will rise for the next million years" and I was moved to write another science-oriented limerick.

The Altantic's three thousand miles wide
And America westward will slide
And I have to divulge
That the size of the bulge
Will result in a much higher tide.

Several very different things are involved.

The science of continental drift tells us that the North Atlantic is getting wider by just over a centimetre a year.
The tides are caused as a result of the gravitational pull of the moon. This means that the part of the sea nearest to the moon is attracted by the moon to form a bulge. One the other side of the Earth the Earth is pulled away from sea, creating a matching bulge.

Because the Earth rotates the bulges move round the world once a day, causing the tides. This bulge can be considered to be a wave moving across the Atlantic and it has a particular wave length.

Resonance then comes into play - rather like a huge musical instrument whene the there is a relationship between the wavelength of the note and the length of the string or pipe generating the sound. The tidle bulge has a wave length and the size of the tides (equivalent to the loudness of the note) depends on the size of the boxslowly gets wider tha amplicifcation of the tides due to resonance will get bigger. However when the Atlantic gets even wider the resonance will decrease and the height of the tide will fall.