A Lukewarm Defense of Imperial Units
In which I defend the use of Fahrenheit over Celsius, sort of defend inches and feet, and make a halfhearted attempt at explaining why I like cups as a unit of volume.
The metric system (kilograms, liters, degrees celsius, etc.), is a better, more standardized, more scientifically relevant set of units. No one remembers the speed of light in miles-per-hour, and no one calculates the radius of the sun in yards. I personally use SI units for literally everything I do in a scientific context.
But, as a proud American who grew up with imperial units, I’m going to offer a lukewarm defense of imperial units, for specific purposes.
No one should use Celsius
This is going to be the most controversial opinion I’ve ever posted: the Celsius temperature scale is actually worse than the Fahrenheit temperature scale. Here’s my argument:
For anything even remotely scientific, using the Kelvin scale is strictly better than Celsius, for one reason only. Absolute Zero, a critically important temperature in physics, is 0° K. In Celsius, it’s -273.15°C, and in Fahrenheit, -459.67°F.
Let’s say you want to calculate the power radiated by a black body at some temperature. You use the Stefan-Boltzmann Law:
Physics is mostly agnostic to units, as in it works equally well in meters or in feet. However, any equation involving temperature requires you to use a temperature scale where 0° is absolute zero. So, I claim that Celsius is no more useful than Fahrenheit for science. Also, room temperature in Kelvin is the easily memorizable 300°K!
So if we’re not going to use Celsius (or Fahrenheit) for science, which is better for everyday life? I actually think Fahrenheit is better.
Temperatures on planet Earth range from about 0°F to about 100°F in human-inhabitable areas. Usually. And since we’re base-ten sorts of creatures, a 0-100 scale is quite natural to use for temperatures! It’s human-referenced, in a sense. In Celsius, I would say that global temperatures range from about -20°C to +40°C. This makes Celsius much less nice, I think, despite the fact that it’s usefully referenced to water. Normally, when I speak about temperature, I’m talking about the weather, not water.
Inches and Feet Are Sort Of Okay
When I’m estimating distances, I very rarely have a ruler handy. Instead, like all of our ancestors, I use my body. And my body is quite a good ruler!
On my index finger, the distance from my fingertip to my first knuckle is pretty close to one inch. The length of my foot is indeed about one foot. The length of my stride is about 1 yard. This is at least somewhat true for most people (though I know it varies quite a bit from person to person). Further, one foot having 12 inches makes it evenly partition-able into halves, thirds, quarters, and sixths.
Now, this isn’t exactly hard in the metric system, either. My knuckle would be 2.5 cm from the tip, and my stride would be a meter. Those are pretty nice units too. But even so, the body-based units of measurement are quite useful for times when I don’t have a ruler, and I claim that absent any nasty unit conversions, inches and feet are about as useful as centimeters and meters. As for miles, well, 5,280 feet in a mile is a truly terrible number.
I Should Find My Wife’s Kitchen Scale
When cooking, I’ve noticed that many European recipes will give quantities of food by mass, instead of by volume. This is great, especially for baking, as the operative quantity in a recipe really is the mass, not the volume.
However, I am very lazy, and wouldn’t use my kitchen scale to measure ingredients even if I could find it. Instead, I use whatever object I have closest to me to measure stuff, which, due to my wife’s love of coffee, is usually a coffee cup. If I fill up a standard coffee cup, I’ve got about one (imperial) cup of stuff in it. This is super useful, because volume can be measured visually in a way that mass cannot. Thus, specifically for cooking, I actually prefer to use the weird imperial volume units over the objectively more accurate metric weights.
Now, I’m not really willing to die on this hill, mainly because the only imperial volume unit I like is the cup. We won’t talk about how many teaspoons are in a tablespoon, or how many tablespoons are in a cup. Frankly, I have no idea, despite googling this at least twice a week. Nor do I know what a fluid ounce is, how it relates to an ounce of weight, or why I should care about either of those units.
My wife would also like to point out that my refusal to use the kitchen scale is one of the reasons I am bad at baking. But I digress.
Conclusion
As a rule, I scrupulously avoid anything controversial on this blog, preferring to stick to controversies a couple millenia old. However, I would really like to know what my readers think, particularly any non-American, Liberian, or Burmese readers who use a sensible system of measurement. Thanks for reading!
I will say that the Fahrenheit argument is still unconvincing. Why should I care about how my temperature scale fits temperatures where other people live? To me, the scale of hot to cold ranges from 0 to 40. Obviously it's suboptimal that it ends at 40, but it sure beats starting at 40.
I would further argue that, even if you live in a place that goes below 0 Celsius, Celsius is still a good scale. Even though we want to talk about the weather and not water, the temperature of the freezing point of water is still pretty important because we have pipes filled with water. Whether the weather is at a point where it will freeze and burst pipes is pretty important, if you ask me.
But I still think kelvins are objectively superior. The issue is that no one else is getting with the program. Which is the only thing that matters in the end.
I don't even remember how long it took me to get used to the Fahrenheit scale when I first came to the US, but I'm sure I kept converting temperatures back in Celsius for a long while... Eventually, the Fahrenheit became comfortable and convenient, and now I find myself converting the other way around... Humans are creatures of comfort, and a small change in temperature makes a big difference, which is why finer gradations are more suitable. A change of ten degrees F (nine, actually) can feel like a big deal, but it's only about five degrees C.