[time-nuts] Anybody have suggestions for time related science fair projects?

[Wayne Holder]

Using a pendulum to measure gravity requires precision timekeeping.
Wikipedia has a nice discussion of this at
https://en.wikipedia.org/wiki/Pendulum#Gravity_measurement

There are number of very clever techniques developed long ago, such as
Henry Kater's design for a reversible, dual pivot pendulum that made it
possible to get quite precise measurements starting about the 1820s.  Then,
around 1835 Friedrich Bessel found ways to simplify calibration of Kater's
design and even cancel out errors due to air drag.  More interestingly,
gravity measuring pendulums became not of the earliest ways used to
standardize the measure of length, which shows how nearly all efforts at
standardization ultimately rely on accurate timekeeping.

Wayne