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Showing posts from October, 2007

The Story of Tower Bridge

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WHY did they build Tower Bridge?

Let me take you back to 1860. London had a problem: TRAFFIC! (Does that sound familiar?) Thousands of people and carts and horses crossed the River Thames. You could take a boat across the Thames, but that was slow and expensive. You could cross London Bridge for free, but it was really crowded. You could swim across, but that, well, it was wet! And in the winter, pretty COLD!

Obviously, the River Thames needed a new crossing. But the new crossing needed to 1) allow carts and horses and people to cross over it, and 2) allow ships to come into the Pool of London. At the same time!

After all, London was one of the world's busiest ports. The big question of the day was: How do you design a bridge which carts and horses can cross over, while tall ships to sail under it?

All sorts of architects submitted all sorts of designs -- there were TUNNEL designs; there were designs for really tall BRIDGES; or BRIDGES with steep roads; there was a design for a &…

Exploring Iceland

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To really understand Iceland, you have to go WAAAAY back in history. To PRE-history, in fact. So let's [REWIND] about one hundred thousand years, to what geologists might call "yesterday." The Late Quaternary Period. (You know the one; it comes after the Pliocene Epoch in the geological timescale. The Quaternary Period started 1.8 million years ago, and we're still living in it today.)

One hundred thousand and ONE year ago, it seems, Iceland wasn't even here. It was just a burp on the ocean floor - deeeeep down beneath the waves. Hot magma spilled from the mid-Atlantic ocean rift and cooled into the land mass which is now the island of Iceland. (Ta da!)

And it's still happening! Iceland is getting larger - about 2 centimetres each year - because Iceland is straddling two geological plates.

Beep! Beep! Beep! (That's me, backing up a bit, to fill you in on some GEOLOGY!)

THE THEORY OF PLATE TECTONICS
"Plate Tectonics" is an idea that once upon a…