Non-SI units are units of measurement that are not part of the International System of Units (SI). While the SI system is the globally recognized standard, some non-SI units are still in common use, often for historical or practical reasons in specific fields.
Here are some examples of units that are not SI units:
- Time: minute (min), hour (h), day (d)
- Temperature: degree Celsius (°C)
- Mass: tonne (t)
- Pressure: atmosphere (atm)
- Length: inch, foot, mile
- Area: acre
- Volume: liter
The table below shows some commonly used non-SI units with their symbols and the physical quantity they measure:
| Physical Quantity | Non-SI Unit | Symbol |
|---|---|---|
| Mass | tonne | t |
| Pressure | atmosphere | atm |
| Temperature | degree Celsius | °C |
| Time | minute | min |
It's important to note that while these units are not part of the SI system, many are accepted for use with SI units. The SI system aims to provide a consistent and standardized framework for measurements, but the continued use of non-SI units often reflects industry-specific conventions or practical considerations.
