People use metric measurements because they are nice and tidy. A metre divides nicely up into 100cm or 1000mm. It’s crisp, clean, easy to work with. In fact the use of “units of 10”, likely evolved from humans using their counting the digits on their hands. Imperial units are messy in comparison. An inch is just something derived originally from what? It was King David I of Scotland who in 1150 defined the ynce, as it was then known as the breadth of a man’s thumb at the base of the nail. In the early 14th century King Edward II redefined it to be “three grains of barley, round and dry, laid end to end”. Lengths of grain? Well, not so surprising considering a barleycorn (or grain of corn, but not maize) was already an Anglo-Saxon unit of length, and likely used well before the 14th century. Ironically, the use of barleycorn as a measure still exists in shoe sizing systems in the UK and North America.
So imperial measures have some grounding in everyday life (of the times anyway). Even today an inch can often be estimated by measuring the width of the thumb. It was the Romans who created the forebears of the foot/pound measurement system. The Roman foot measured 11.68 modern inches, divided into 12 uniciae. Five feet comprised one passus (pace), and the mille passus (mile) was 1000 paces long. Ironically, since the adoption of the international yard in the 1950/60s (1 yard = 0.9144m), inches are now based on the metric system, i.e. 25.4mm.
Metric measurements are now derived using science, which I have to say lends an element of unnaturalness to them. For example 1 metre is defined as “the length of the path travelled by light in a vacuum in 1/299,792,458 of a second”. Yawn. But although we happily use metric, there are instances where we seem to have shunned it. Time for example. Why don’t we have metric time? Why aren’t there 20 hours in a day, or 30? A day is simply the time it takes for the earth to rotate once, which is really kind of arbitrary. Why do hours not have 100 minutes? Based on the current definition of a minute, that day would be 14.4 metric hours long… so to get to 20 we would have to reduce the size of a minute. For time I guess we decided a modified form of the Babylonian sexagesimal system made more sense.
Metrication occurred in Canada in 1971, 50 years ago. But I think you would find many Canadians are quite impetric, using a combination of both systems. I use inches and feet when it comes to building, or woodworking, pounds when it comes to buying fruit and vegetables at the grocery store (even though inventory management uses kg), litres when buying liquids, kilometres when on a road-trip, degrees Celsius when thinking about outdoor temperature, and degrees Fahrenheit when using the oven. What a mixed bag. Bananas are a great example. Go to the store, and they are sold as lbs, with kg in smaller print. Pounds is a small quantity, and is strangely easier to identify with (and it “seems” cheaper than the price in kg). Look at a real estate site, and chances are the land area will be represented as acres – why not hectares? Because 1.2 acres seems like more than 0.5 hectares. Britain is not much different. Officially a metric country, imperial measures are still used for road distances.
But non-metric units are not even standardized. One would think that maybe imperial measures were from the US, but that would be be wrong. The US uses the US Customary System, while the Imperial System is actually British, but both are derived from English units. For the most part they are the same, but some things are slightly different. Ask for a pint in a British pub, and you would receive 568.261ml of beer. A US pint is only 473.176ml. Products in Canada are also an oddity. Something like a carton of oat milk may be 946ml, but why? Why not 1000ml? The reason is that 946ml = 2 US liquid pints. A 796ml can of tomatoes instead of 800ml? 38 fluid oz.
Measuring things is challenging, but in some ways that’s okay because going impetric allows you to choose the best of both worlds. The imperial system has a certain character about it. The colourfulness and descriptiveness of the imperial system is due to the fact that it is rooted in imagery and analogies that make intuitive sense. A foot is more descriptive and likely more human than metric.
working by hand 