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On Wednesday, 26th of October 2005, almost 220 junior students, ages 7-13, took control of IUB’s Conrad-Naber-Lecture-Hall and bombarded Michael Bau, Professor of Geosciences, and Stephan Rosswog, Professor of Astrophysics, with questions dealing with the issue “Why do rocks exist?”
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Oct
27, 2005]
Beginning with Michael Bau munching on a piece of shale and Stephan Rosswog eating a Mars bar, the children where informed that geologists regularly ‘eat’ stones to distinguish sandstone from slate. Asking the children whether they had ever formed snowballs, Michael Bau clarified diagenesis, the process provoking the hardening of stones.
But what is a rock or stone? The children wanted to know. Prof. Bau explained to them that a stone has three characteristics: It has to be solid, natural, and inorganic. This answered the audience’s question why cement cannot be considered to be a stone. Having learned that stones are comprised of minerals and elements. Yet not fully satisfied, the children enquired where elements come from.
At this point, Prof. Rosswog took the children on a journey into space. Saucer-eyed the children watched the birth of a star, followed by a flight of meteorites which eventually reached planet earth. Here, the origin of stones became clear: The elements stones consist of are generated in explosions ending the life of a star. Prof. Rosswog was urged to show the travelling of meteorites over again. The children learned that meteorites are still racing to earth today and that the ones, which do not make it to the ground, are ‘falling stars’ which can be witnessed in night-sky.
The audience discovered that the moon was once a piece of the earth blown away by a colliding planet the size of Mars, long, long ago. ‘But where is the dent?’ an 11 year old girl enquired. Referring to the previous lecture ‘Why there is no Largest Number’ Michael Bau explained that this had happened 4.5 billion years ago.
In the end the children became conscious that stones exist in space, on earth and even in our bodies - as bones, teeth and kidney stones. They are made from ‘nutrients’, which basically are the elements of stones, washed out of rocks, which have entered the water cycle of earth. An interesting experiment followed. One child conducted the dissolution of stone powder with hydrochloric acid, demonstrating this process most effectively, accompanied by the astonished noises of the audience.
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