Measuring One Second: Official Count & Clock Corrections

In summary, the official count of one second has evolved over time, from being defined as a fraction of a mean solar day to now being measured as a certain number of oscillations of a cesium-133 atom. The discrepancy of 4 minutes in a day is due to the Earth's rotation and orbit around the sun, and our clocks are designed to account for this difference. The number of ticks an electric clock goes through before turning another second can vary depending on the type of clock.
  • #1
kyle_soule
240
1
What is the official count of one second? What I mean by this is: how would one go about measuring one second exactly? Basically, at the creation of a second, how was it measured?

Also, if a day is 23 hours and 56 minutes, wouldn't our clocks be off 4 minutes after each day? I understand the system of correction, but until time is 'corrected' for our clocks, we have the incorrect time, correct?
 
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  • #2
The old defintion was 1/86,400 of a mean solar day and then it was 1/31556925.9747 of a tropical year, but since 1967 it has been 9,192,631,770 oscillations of a cesium-133 atom.
 
  • #3
23 hrs 56 min. is time for one complete rotation of the Earth on its axis. During this time the Earth has moved in its orbit around the sun. The extra 4 minutes is needed to keep the same face toward the sun.
 
  • #4
Originally posted by mathman
23 hrs 56 min. is time for one complete rotation of the Earth on its axis. During this time the Earth has moved in its orbit around the sun. The extra 4 minutes is needed to keep the same face toward the sun.

That's why it's called a siderial day. Because it is in relation to the backround of stars, not the sun we orbit.
 
  • #5
People, people, people [mathman and ORW] I knew all this, I was simply asking would our clocks not be off each day increasing by 4 minutes.

jcsd, would you happen to know how many ticks an electric clock goes through before it turns another second?
 
  • #6
A day is "noon to noon" which means we return to the same position wrt to the sun, not the stars. Hence our day is 24 hours long. The reason our clocks arn't off is because we build them to make 24 hours to be 24 hours. Its all arbitrary really.
 
  • #7
Originally posted by kyle_soule
People, people, people [mathman and ORW] I knew all this, I was simply asking would our clocks not be off each day increasing by 4 minutes.

jcsd, would you happen to know how many ticks an electric clock goes through before it turns another second?

No I ****ing don't
 
  • #8
Many electic clocks simply run a motor on 60Hz, thus the speed is tied to the frequency of your power line.

Digital clocks run on a crystal, the frequency of which depends on a selection make by the clocks ciriciut designer. It could vary significaly from clock to clock.
 

FAQ: Measuring One Second: Official Count & Clock Corrections

1. How is one second defined and measured?

One second is defined as the duration of 9,192,631,770 oscillations of the cesium 133 atom. This is the internationally agreed upon definition of one second and is measured using atomic clocks.

2. What is the process for an official count of one second?

An official count of one second is done by counting the number of oscillations of a cesium 133 atom. This count is then compared to the internationally agreed upon definition of one second to ensure accuracy.

3. How are clock corrections made?

Clock corrections are made by comparing the time measured by a clock to a more accurate reference clock. Any discrepancies are then corrected to ensure the clock is displaying the correct time.

4. Why are clock corrections necessary?

Clock corrections are necessary to maintain accurate timekeeping. Over time, clocks can experience slight variations in their timekeeping due to factors such as temperature changes or mechanical wear. These corrections help to ensure that clocks remain accurate.

5. Who is responsible for making clock corrections?

Clock corrections are the responsibility of organizations such as the National Institute of Standards and Technology (NIST) in the United States or the International Bureau of Weights and Measures (BIPM) internationally. These organizations oversee the official timekeeping and make corrections as needed to maintain accuracy.

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