Because of all the sand which is there...
Image: Alan Parkinson, shared on Flickr under CC license
Sand is the most extracted solid material in the world.
That's the answer to one of the questions on the Gapminder Misconception test as well.
This Guardian piece is the latest in a series of articles suggesting that the world is running out of this material.
It’s used in everything from swimming-pool filters, to creating metal castings and oil wells to smartphone screens and toothpaste. And glass of course... and there's a lot of that around - particularly in modern architecture.If you say to students that we are running out of the sand, their first response might be... what about all the deserts there are in the world, or why not take it from some of the beaches in the world?
But it's not as simple as that.
Beach sand is salty for example, which would rot any concrete that was made with it. Its use in construction is banned. The tumbling motion of the oceans also changes the nature of the sand grains reducing the surfaces to which they can bond with other materials.
This means that even Dubai... in a desert... has to import the sand it uses for construction.
And some resorts have even resorted (sorry) to 'fake sand' which is harmful to wildlife.
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