Seconds
Abbreviation/Symbol:
s
Worldwide use:
The second is the International System of Units (SI) unit of time and is used across the globe. In everyday life seconds are the building blocks of minutes and hours underscoring its importance in worldwide time keeping.
Definition:
Its definition is based on the transition between two hyperfine levels of the ground state of the cesium-133 atom, specifically it is the duration of 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.
Historically it was defined as 1/86,400 of a solar day. This definition was imprecise due to variations in Earth's rotation and so to achieve greater accuracy the second was redefined in 1967 based on atomic time.
Origin:
The second as a unit of time has its origins in ancient civilizations where time was primarily measured based on the motion of celestial bodies.
The division of the day into smaller parts can be traced back to the Egyptians who used sundials to divide daylight into 12 parts. The ancient Sumerians and Babylonians introduced the sexagesimal (base-60) system which divided an hour into sixty minutes and a minute into sixty seconds.
It wasn't until the 20th century that the definition of a second was standardized based on atomic properties of Cesium. In 1967 the International System of Units redefined the second as the duration of 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.
Common references:
1 second (s) = 1,000,000 microseconds (μs)
1 second (s) = 1000 milliseconds (ms)
60 seconds (s) = 1 minute (min)
3600 seconds (s) = 1 hour (h)
86,400 seconds (s) = 1 day
Usage context:
Seconds are crucial for measuring short time durations. They are widely used in sports where even fractions of a second can determine the outcome of a race or competition. In scientific research they provide a time standard for experiments and observations.