Eli5 What is the story with those 4 armed clocks at swimming pools lanes?

Question

Sometimes they have 4 arms of different colors. The markings with a marking every 5 minute mark, and bigger ones at the 15 , 30, 45, 60 markings…Clearly the markings represent increments of an hour

In: 3

Answer 1

Swimmers (much like runners) like knowing how fast they’re going. Perhaps you want to do a bunch of laps on a specific interval of time.

The clock is what you use to keep track of that. It’s aggressively colored to make sure that you can see it when your head pops up at the end of a lap. The second hand is particularly large to ensure you know what second you ended the lap on.