One of the most important, and perhaps surprising, human achievements during the nineteen and twentieth centuries was the adoption around the world of a common language of measurement. Ronnie Cohen provides an illustration of the benefits this can bring.
I recently bought noise-cancelling headphones for my mobile phone. One thing I noticed was that the operating instructions were provided in 15 different languages. The specifications printed on the box appeared in 3 languages. The battery installation instruction sheet was written is 19 languages and the European Guarantee Information Document was written in 22 languages – none contained any measurements. However, the measurements on the box and in the operating instructions were provided in the one common measurement language that we know as the metric system. All the translations used common measurement units and symbols, even in the non-Latin alphabets used in the Greek and Russian versions of the operating instructions. The number formats varied slightly as some countries use the comma and others use the dot as the decimal point. The same can be said for the thousands separator.
Most of the units appeared in the ‘General Specifications’ section of the operating instructions:
- Driver units: 30 mm
- Maximum input: 28 mW
- Impedance: 220 ohms at 1 kHz (when the power is on), 45 ohms at 1 kHz (when the power is off)
- Sensitivity: 115 dB/mW (when the power is on), 110 dB/mW (when the power is off)
- Frequency response: 10 Hz – 22 000 Hz
- Total Noise Suppression Ratio: Approx. 13 dB
- Cable: Approx. 1.2 m
- Power source: DC 1.5 V
- Mass: Approx. 150 g including battery, not including cable
- Talk microphone: Open circuit voltage level -40 dB (0 dB = 1 V/Pa)
Other measurement units were found elsewhere. In the ‘Features’ section, a feature of “300 kJ/m3 Neodymium magnet” described sound quality. In the ‘Included Items’ section, a footnote for the approximate hours of battery life reads “At 1 kHz, 0.1 mW + 0.1 mW output”.
This single product contained the following different measurement units:
- Millimetres (symbol: mm) – unit of length
- Metres (symbol: m) – unit of length
- Megawatts (symbol: mW) – unit of power
- Ohms (symbol: the Greek lower case omega) – unit of electrical resistance
- Hertz (symbol: Hz) – unit of frequency
- Kilohertz (symbol: kHz) – unit of frequency
- Decibels (symbol: dB) – unit of sound
- Volts (symbol: V) – unit of electric potential
- Grams (symbol: g) – unit of mass
- Pascals (symbol: Pa) – unit of pressure
- Kilojoules (symbol: kJ) – unit of energy
These are all the different measurement units found in a single multi-national product. This product shows the importance of measurements in our lives and of one common measurement language that everyone can understand and use. It helps us to compare one product with rival products on the market, no matter where they are produced or sold. While there are linguistic differences across the world, the metric system is a common measurement language that unites us all (at least in the context of measurement).