Figuring Out The Peculiar Measuring Systems Used In Kenya

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

23 October 2005

One of the great peculiarities of Kenyans is that our tailors and carpenters buy their materials in metric units (metres), yet they take their measures in imperial units (inches and feet). Converting from one system to the other can be tricky, but by international agreement, one inch has been defined as exactly 2.54 centimetres. Thus sometimes it is referred to as the “metric inch” – an oxymoron of sorts.

With this definition, it is easy to see that one foot (12 inches) is equal to 30.48cm (12in x 2.54cm). On the other hand, one metre (100cm) is 39.37 inches (100cm divided by 2.54cm). The only problem here is that it is difficult to make out the 0.37 fraction from the marking on a ruler.

The imperial side of the ruler shows inches divided into halves (that is 0.5), quarters (0.25), eighths (0.125) and, sometimes sixteenths (0.0625). Thus the fraction 0.37 is slightly less three eighths (3 x 0.125 = 0.375). To make out one metre from a tape measure that only has inches, you would have to first establish whether the smallest division marked is an eighth or a sixteenth.

If it is an eighth, then one metre is 39 inches and three small divisions – actually, just below the third mark. If the smallest division is a sixteenth, then a metre will be 39 inches and six divisions – just below the sixth mark. Complicated in deed. That’s why I can never understand why our fundis like inches so much…

Another Kenyan peculiarity is to be found in toothpaste: some tubes show the quantity in grams and others in millilitres. The question that arises is, how many millilitres make one gram? The answer to that depends on the substance we are talking about. And to complicate matters further, brand X toothpaste is not the same material as brand Y!

If it was water, one gram would be one millilitre, but one gram of toothpaste, is more than one millilitre of the product. What is the difference between the two measurements?

Litres and millilitres measure volume; grams and kilograms measure mass (not weight!). Volume is simply the space occupied by a substance and mass is the quantity of matter in the substance.

In everyday practice, we use volume to measure liquids and mass for solids. Thus cooking oil will be sold in litres and cooking fat in kilograms. But one kilo of fat is NOT the same quantity as one litre of oil.

Toothpaste is a soft solid or a hard liquid depending on the brand you chose. So it may be difficult to judge which system to use. In such a case, it would be fair to go with the mass. It is for this reason that cooking gas is sold in kilograms: when inside the cylinder it is a liquid but when it comes out it is a gas.

What about mass and weight? Are they the same? Well, that’s a story for another day. For now it will be enough to say that mass is what you measure with a SCALE balance and weight is what you get from a SPRING balance. Guess which of the two is more reliable.