Wednesday, 13 February 2008

Are we all made of sand?

sand dunes
Sand is a fascinating matter. When densely packed, sand can be solid as a rock. Add a bit moisture and you can make sculptures out of sand. But sand can also behave like a liquid. The change between the two states can be very abrupt and is not yet fully understood.

Recently, at the University of Chicago, physicists have shot a stream of glass beads on a small coin-like circular surface. The glass beads swash away in the manner of a liquid, forming a bell-like hollow cone structure. Just the same can be seen when the water jet from a hose hits a small surface, for instance a finger tip, at a certain speed. As soon as the right speed is reached, the bell-like structure forms. Every child has seen it when playing with water.

The interesting point of the Chicago experiment is its purpose. It has been designed in order to simulate findings of an experiment with subatomic particles. We all are made of atoms, and all atoms are made of quarks. Thus, we all are made of quarks.

At the Relativistic Heavy Ion Collider (RHIC), quarks have been shot with near light speed on a gold surface. The researchers expected the quarks to behave like a gas but were very surprised to see them form a bell-like liquid structure as if they were a water jet hitting a coin.

Quarks are thought to be particles, and this led to the idea of the sand analogy. Sand can exist in all three states of matter: solid as sandstone, liquid as quicksand and gaseous as standstorm. The Chicago experiment has shown that sand particles, under certain conditions, behave just like the quarks at the RHIC.

The idea that we may be made of something like sand is fascinating because of its sudden changes and non-steady behaviour. I guess that such chaotic elements, butterfly effects on subatomic levels, are the reason why life has evolved.

Photo credit:


Lirone said...

Interesting piece. Adding this to some of the themes in your other post immediately made me think of the Douglas Adams article Is there an Artificial God, which has a long section on the "Four ages of sand". Among many other things, he talks about sand, in the form of lenses and of silicon, radically changing our view of the world. One of my favourite articles!

Christian said...

Thanks for the hint. The Douglas Adams article is great. I think I'll come back to it in an upcoming post.