The Scientist’s Essay for Grade 3, 3. Investigating Standard Measures
Why are Standard Measures Important?
Not long ago a satellite on its way to Mars was lost because the ground controllers sent instructions to the steering rockets in the wrong units, sending it hopelessly off course.
If you judged the practice of science from the movies, you might imagine that scientists work alone in secret laboratories, entrusting their discoveries, if at all, only to a few trusted coworkers. If that image were accurate, we would have little need for standard measures — if I want to measure lengths in units based on the length of my right pinkie finger, what difference does it make? And if I record my results in a code known only to me, who cares?
But that’s not how science works. The remarkable success of the scientific project is due largely to its collective nature. Results are shared, criticized, reproduced, refuted, refined, debated, sometimes rejected. An experimental result or theoretical insight, no matter how remarkable, does not become part of science until it is effectively communicated to the scientific community.
The central role of communication means that a shared language is essential, and that language extends to the units we use to communicate the results of measurements. If I report that the density of a new material is 1470.3, an experimentalist in Germany or a theorist in Japan who wants to compare her results with mine needs to know whether that value is in kilograms per cubic meter, grams per cubic centimeter, pounds per cubic foot, or something else. And if it is something else, she needs some way to convert it to other units — otherwise the measurement provides no useful information. Not long ago a satellite on its way to Mars was lost because the ground controllers sent instructions to the steering rockets in the wrong units, sending it hopelessly off course.
Even within science, standardization is far from complete. Scientists have formally agreed on the Systeme Internationale (SI) of units, based on meters, kilograms and seconds. But in practice, subfields develop their own units, and I sometimes have trouble reading papers even in my own field that are written by chemists, because they tend to use slightly different standard units from those preferred by physicists. It’s not a big problem, because I can always convert from their units to mine, but it impedes communication like having to look up a word in the dictionary.
—Roger Tobin
