Students replicate ancient experiment at Qutub Minar

An experiment to measure the earth's circumference, claimed to have been conceived 2,300 years ago, was carried out by more than hundred school students here today by using Qutub Minar's shadow.
For the first time Qutub Minar was used as a towering gnomon- an object that by the position or length of its shadow serves as an indicator to measure the earth's circumference.
Known as 'Eratosthenes' experiment, it saw the students also measuring the shadow of sun using gnomon sticks.
The students also measured the shortest shadow at local noon on autumnal equinox which falls on September 23 every year.

The event was organised by Science Popularization Association of Communicators and Educators (SPACE).
"Despite issues like protruding balconies from the Minar and the shadow falling on different structures, most students achieved above ninety-five per cent accuracy in measuring the earth's circumference," said SPACE president C.B. Devgun.
"Gnomons of all sizes and shapes have been used previously. For instance, huge objects such as samrat and ram yantra at Jantar Mantar and sundial at Barapullah have been used for experimentation ," he added.