Posts tagged ‘clock’
What Do AM and PM Stand for?
You might see these acronyms every day and never even think about what they actually stand for. But, at some point, you’ve probably set your alarm for PM and been late for something in the AM.
I asked my dad about AM and PM at the curious age of five. He had a really good answer. It wasn’t the right answer; but, it was a good answer.
According to him at the time, “AM” stood for “At Morning” and “PM” was “Past Morning.” It made sense and kept my mind at bay until now, and it’s not that far from the actual Latin translation.
AM is a Latin acronym for Ante Meridiem, which is “before midday” when translated to English.
PM is Latin for Post Meridiem or “after midday.”
Now, if you want to showoff you can lose the acronym and throw down, “post meridiem” the next time someone asks “AM or PM?”
BrokenSecrets.com [available in the Amazon Kindle Store]
Source: WP
Leap Years and Leap Seconds
Happy New Year!
You probably know that leap years occur every four years. On leap years we add an extra day to keep our clocks and calendars in sync with Earth’s rotation.
On the other hand, most people don’t know about leap seconds. Leap seconds are used for the very same reason as leap years, to keep our clocks in sync with Earth’s rotation.
Because Earth’s rotation varies, leap seconds are added or subtracted up to twice per year when needed. Leap years add a day in February while leap seconds can be added at midnight on December 31st or June 30th when necessary.
An extra day on the calendar isn’t going to go unnoticed, but an extra second is difficult to sense. That’s why most of us don’t know about them. Accurate time keeping devices (atomic clocks) are updated appropriately and you may notice the update on connected devices like cell phones or GPS units, but generally it goes unnoticed by nearly all of us. The last two leap seconds were added on New Year’s Eve of 2005 and 2008. The next time a leap second will be added is not known.
Here’s a video that shows an extra second inserted between 59 and 00 on an atomic clock.
BrokenSecrets.com
Sources: WP – Leap Year, WP – Leap Second, TimeAndDate.com,
Broken Secrets 