Centimeter-Gram-Second (system of units)
(CGS)
Description
Centimeter-Gram-Second (CGS) System of Units: Measurement
Every day people measure things. You have some units when you check your height, or when you weigh things, or when you try to find out how fast something is going. One of the most important ways to measure things scientifically is the Centimeter-Gram-Second (CGS) system, among all others and it is one of the oldest. The system made it possible for us to understand how things are measured today.
What is CGS System?
System of CGS units refers to metric units such as:
- Length in centimeters (cm)
- Mass in gramme (g)
- Time in seconds (s)
This metric system was made long back in the 1800s and was commonly used by scientists because it was simple to comprehend and apply. People earlier used plenty of confusing and local systems before the CGS system came into existence. It made available to all one mode of measuring things, very much required in the fields of chemistry as well as physics.
What Does “CGS” Stand For?
These letters, ‘C’, ‘G’, and ‘S’, stand for simple basic units:
- C = Centimetre (1/100th of a metre)
- G = Gramme (one thousandth of a kilogramme)
- S = Second (the standard unit of time)
These are used to find the value of lots of materials, such as speed, force, energy or power, and many other things.
A Few Common CGS Units
The CGS system has only three base units, but this should not imply that they are to be restricted to just these. Some examples include:
| Amount | CGS Unit |
|---|---|
| Length | cm |
| Mass | g |
| Time | s |
| Speed | cm/s |
| ForceEnergy | Erg, erg |
| Force | Dyne: dyn |
| Pressure | Ba (Barye) |
Let's take a closer look at some of these:
Dyne: A teeny bit of force. One dyne is the amount of force needed to speed up a 1-gram object by 1 cm/s².
Erg: A very small amount of energy. One erg is the work done moving something 1 centimetre against a force of 1 dyne.
Barye: So, a barye is exactly equal to 1 dyne per square centimeter of pressure.
These may seem small, but they are invaluable to scientists, particularly as they work with small or microscopic systems.
What Makes CGS Different from SI Units?
SI is currently the world’s most widely used system. SI uses:
- Meters (m) instead of centimeters
- Kilograms (kg) instead of grams
- Seconds (s) remain the same
So why did we shift from CGS to SI?
Joule (J) and Erg are both energy units. The change is because SI units are bigger and better for engineering, industry, and everyday life. Most practical uses don’t need CGS units like erg and dyne because they are too small.
Where is the CGS System Still in Use?
Most countries and groups have now shifted to SI units, and only a few still use CGS—in theoretical physics and astrophysics and in some older scientific writing. For example, in the field of electromagnetism, the CGS system makes some equations easier for the working mind to understand.
CGS-based equations are still being taught in some elementary science classes in colleges and schools.
Pros of CGS
- Intuitive and Easy: as the metric system base.
- Handy in Small Systems: Especially helpful in physics studies and laboratory work that relate to small systems.
- Clean Physics Equations: Removes unnecessary constants, such as ε₀ and μ₀ in SI, from some equations, making them neater.
This system of units is not ideal for large-scale use since its subunits are too small to measure big things, such as buildings or cars. Today, however, it is not universal since most businesses, governments, and scientists use the SI system. Communication at an international level could be fraught with confusion, as it is only conventionally referred to as CGS and certainly not a global standard.
Final Thoughts
The system of Centimeter-Gram-Second units was a very big deal in science history. It offered scientists a much good measure of the world around them that was reliable and used the same units every time. The SI system has mostly taken over, but CGS is still useful for learning the basics and solving certain scientific problems.
Knowing about CGS helps us know how the measurements have changed since then and why precision in units matters so much, especially in a world that science and technology are based on.