Wednesday, August 3, 2011

World’s oldest protractor?

This object was found more than a century ago in an Egyptian tomb belonging to an ancient architect who lived around 1400 BCE. In the Turin museum where it’s displayed, the artifact is identified as a decorative case for a balancing scale. However, physicist Amelia Sparavigna thinks it may be the oldest surviving protractor. From New Scientist:
 Data Images Ns Cms Dn20748 Dn20748-1 300
The key, she says, lies in the numbers encoded in the object’s ornate decoration, which resembles a compass rose with 16 evenly spaced petals surrounded by a circular zigzag with 36 corners.
Sparavigna says that if the straight bar part of the object were laid on a slope, a plumb line would revealed its inclination on the circular dial.
The fraction of one-sixteenth features in a calculus system the Egyptians used, says Sparavigna, and they also identified 36 star groups called the decans, which later formed the basis of a star clock. She suggests the object was “a protractor instrument with two scales, one based on Egyptian fractions, the other based on decans”.

No comments:

Post a Comment