From a Swinging Chandelier to Global Positioning Systems
By Steven Strogatz
Calculus has unraveled mysteries that puzzled scientists for centuries, and it has led to technologies they never would have imagined.
This Article From Issue
March-April 2021
Volume 109, Number 2
Page 106
Legend has it that Galileo Galilei (1564–1642) made his first scientific discovery when he was a teenage medical student. One day, while attending Mass at Pisa Cathedral, he noticed a chandelier swaying overhead, moving to and fro like a pendulum. Air currents kept jostling it, and Galileo observed that it always took the same time to complete its swing whether it traversed a wide arc or a small one. That surprised him. How could a big swing and a little swing take the same amount of time?
QUICK TAKE
- Galileo Galilei studied pendulums in the 16th century, but their full potential would not be realized until the discovery of calculus a century later.
- The sway of a pendulum regulates the timekeeping of metronomes and grandfather clocks, and the concept behind the movement extends to any vibrating object.
- Oscillating ions operate on the same principle as pendulums. Their regularity provides atomic clocks with the precision required to operate the Global Positioning System.
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