Metric time facts for kids

Metric time is a way to measure how long things take using the metric system. The main unit for time in this system is the second. You can also use smaller units, like milliseconds, or larger ones, like kiloseconds. These names come from metric prefixes. Even though we use minutes, hours, and days every day, they are not officially part of the metric system. They are just accepted to be used with it.

How Metric Time Started

The metric system first began in France in 1795. At first, it had ways to measure things like length, weight, and volume. But it didn't have a special way to measure time.

A few years earlier, France tried using Decimal time, which divided the day into 10 parts. But this idea was stopped when the main metric system started.

Later, in 1874, scientists like James Clerk Maxwell helped create the Centimetre-gram-second (CGS) system. This was an early version of the metric system that included units for time.

The Second Becomes Official

The "second" became an official base unit of the modern metric system, called the International System of Units (SI). This happened in 1954 at a big meeting called the General Conference on Weights and Measures.

Later, the definition of the second was made even more exact. It was defined by how fast a special atom, caesium-133, vibrates. This makes sure the second is always the same, no matter where you are.

Other Ideas for Time Units

People have had other ideas for metric time units. In 1794, a scientist named Joseph Louis Lagrange suggested names like déci-jour (deci-day) and centi-jour (centi-day). These would be based on dividing the day into 10 or 100 parts.

Other ideas included units like "tick," "meck," or "chron." These were also based on dividing the day into different parts. However, none of these new units became popular or widely used.

Metric Time in Computers

Metric time is very useful for computers. This is because computers work well with numbers based on 10.

• Unix time measures time as the number of seconds since January 1, 1970.
• Microsoft's FILETIME counts time in tiny parts (100 nanoseconds) since January 1, 1601.
• VAX/VMS systems count 100 nanosecond parts since November 17, 1858.
• RISC OS counts centiseconds (hundredths of a second) since January 1, 1900.

These computer time systems are not perfectly smooth. They sometimes have small pauses for leap seconds, which are extra seconds added to keep time accurate.

Challenges with Metric Time

One challenge with metric time is how we use the prefixes for larger time units. The SI system has prefixes for units that are 10, 100, 1,000 times bigger, and so on.

For example:

• A decasecond is 10 seconds.
• A hectosecond is 100 seconds (about 1.6 minutes).
• A kilosecond is 1,000 seconds (about 16.6 minutes).

The next official SI prefix jumps to a megasecond, which is 1,000,000 seconds. This is about 11.5 days. After that, a gigasecond is 1,000,000,000 seconds, which is over 31 years!

These big jumps make it hard to talk about everyday time, like hours or days, using only the official SI prefixes. To make metric time easier for human life, we would need new prefixes for units like:

• 10,000 seconds (about 2.7 hours)
• 100,000 seconds (about 1.15 days)

See also

In Spanish: Tiempo en unidades métricas para niños