After studying and teaching science for 30 years, I thought I knew everything about Système International (SI) units. Turns out I didn’t. Editing has introduced me to a whole new, unsuspected realm of SI idiosyncrasies and conventions.
Some fundamentals
I edit science articles before they are submitted to a wide array of journals on subjects including geology, biochemistry, genetics and medicine. Most of these articles include SI units in one form or another. If you’re not a science editor, you may recall vaguely from school that there are seven fundamental SI units. These are the second, metre, kilogram, ampère (for current), kelvin (for temperature), mole (for amount of substance) and candela (for light intensity).
In addition, there are many derived SI units, like the newton (N), which measures force. As the name suggests, these are derived in various ways from the seven fundamental units.
Time, temperature and more
So far, so good. Now for a few technical details. Some of these SI units, like the candela, are rarely seen, if ever. Time, in seconds, is very common, but sometimes the time is given in minutes or hours. These have standard units, although they are not SI units. Most journals prefer min for minute and h for hour. These might be seen when the author is telling you how long they centrifuged something (2 min) or kept it in the fridge (4 h). However, the journal guidelines do vary, with some journals preferring hr to h.
Temperature is a curious one. Kelvin (K) is never used; the convention is to use degrees Celsius (°C). The correct way to write a temperature is 25 °C (space between quantity and symbol, but no space between the little circle and the C). The space between the quantity and symbol is standard, so 25 kg is correct. However, there is no space between the quantity and the percentage sign: 56% is the correct format.
Thankfully, there is no problem with Americanisms; Fahrenheit is never seen, nor are miles, pounds or ounces.
Volume is another curiosity. As a teacher, I only ever saw ‘ml’ for millilitres, whether in a textbook or on a measuring cylinder. In the publishing world, mL is the preferred unit, as it avoids confusion with the number 1. At first, I refused to believe this, thinking there must be some mistake. But mL it is. I did find one journal who specifically state in their guidelines that ml must be used. For the rest, mL is the norm.
Dashes and drama
Similarly, the en dash is the norm for ranges (eg 30–40 m), apart from one journal I saw where the hyphen was specified for ranges. Their quite vociferous text implied that it was an assault on the senses to use an en dash for ranges. I suppose there are so many journals that the idiosyncrasies of individual founders or editors are bound to creep in. On a lighter note, the journal guidelines of some smaller journals are written in such excruciating English that one does not know whether to laugh or cry. Apart from the appalling grammar, within the same paragraph one will encounter ml and mL, color and colour, analyse and analyze, all while insisting that authors are consistent in their submissions.
Consistency
I have gradually learnt what to look out for in terms of consistency. Most authors find it difficult to keep abbreviations consistent, switching back and forth between the abbreviation and the full term. I think this is true for all fields, not just science. If there are °C, one or more will always be wrong. Statistical probabilities are seldom presented consistently. I don’t mind if one writes p<0.05 or P < 0.05, but it must be consistent and rarely is. Headings and sub-headings, of course, are all over the place, with sentence case and title case usually mixed up.
Where did you buy it?
A last detail that was new to me as a science editor, was the necessity of indicating the supplier of a piece of equipment. This applies equally to microscopes, statistical packages and computer programs. It is common to see phrases like ‘the VP1 gene was amplified using Prime STAR HS DNA polymerase (Takara Bio Inc., Kusatsu, Japan)’. If the supplier is American, the state has to be given. I have learnt that many things come out of Cary, North Carolina, as in ‘… using SAS software version 9.4 (SAS Institute, Inc., Cary, NC, USA)’. Microscopes tend to be German or Japanese.
Once one gets used to it and knows what to look for, science editing is very interesting and you learn all sorts of unexpected things – the mating behaviour of the Japanese Rockfish was the last article I tackled.
Photo: Freepik
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