The pendulums of two pendulum clocks hanging on a wall gradually become aligned. When many fireflies gather in a tree, they gradually begin to flash at the same time, creating a larger accumulated ...

Newly created by Hardin Planetarium, we explore how our ancestors kept track of the change of time. Learn the basics of sundials, including how to build one. Discover why ancient peoples divided the ...

Here are the measurements I used, starting with the longest pendulum and moving toward the shortest: 230mm, 211mm, 196mm, 183mm, 170mm, 159mm, 149mm, 140mm, 131mm, 124mm, 117mm, 110mm, 105mm, 99mm ...