The Vertical Earth Kilometre

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Understanding very long lengths is not easy. Other than looking into the distance, it is quite difficult for most people to think about kilometres, for example. You can easily think about a 50 metre long swimming pool, or a 100 metre long race track in sport, but after that it gets tricky to think about.

Some people are quite obsessed with visualising mathematical concepts. In 1977, the German installation artist Walter De Maria created a permanent art installation in Friedrichsplatz Park in Kassel, Germany. It is a 5 cm diameter brass rod that is 1 kilometre long. It has been embedded straight down into the earth so that only the top surface shows. So you have to imagine the whole length. All you can see is the round brass top in the centre of a 2x 2 metre red sandstone plate.  The rod has a mass of 18 tons. The rod cut through 6 geological layers and took 79 days to install. Some people thought it was crazy to spend millions of dollars on something you can’t even see, but have to imagine. What do you think?

Walter De Maria also created The Broken Kilometre in 1979. As you might realise, he has displayed another 5 cm diameter rod, but this time you can see it, not as one total length but as 500 two-metre long highly polished lengths of brass, placed together as 5 columns with 100 rods in each column. This is a permanent installation at the Dia Art Foundation in New York. It has a mass of 17010 kg.

What might your class do to imagine a one kilometre length?