This year is a great year to teach STS because we have a leap year, and students can learn alot about STS by studying time.

As many of you know, “time” is a social construction, and it makes for a great topic to teach students about standards, units of reality, and the basic infrastructure that makes “modern” life possible. What also makes time such a great topic is how seemingly “naturalized” it has become (or been packaged to be). Time corresponds with the predictability of the Earth’s revolutions; times is, ironically, one student said, “in synch with natural rhythms.”

Leap years remind us where all that went wrong. It is important to convey to students one idea above all: the second has changed duration over time.

When early numerized “time” was being developed under the sexigecimal system (system of count according to measures of 60) by Egyptians and Bablyonians, the whole day was being “diced” into smaller and smaller units, down to the second. And this lasted for a long time, although the second was occasionally refined, it was not until 1954 that the International Committee for Weights and Measures redefined the duration of the second, this time in fairly scientific terms. Six years later, in light of the advent of the atomic clock, the second was redefined once again. Suddenly, the accounting for time started with smallest unit and “days” where built from there (rather than the inverse process, where the day was the unit to dice-up into smaller units).

Now, what’s interesting about this, in light of the leap year, is that there is now a rogue second that must be accounted for:

The International Telecommunication Union’s Radiocommunication Assembly, otherwise known as the international authority that keeps close tabs on time, will debate a philosophical question this week: They will decide whether to eliminate the leap second and in doing so break its tie to astronomical time.

“Leap seconds”

are added occasionally to synchronise ultra-accurate atomic clocks with the real length of the day, which varies slightly because of irregularities in Earth’s rotation around its own axis.

What is so nice about this example is that it will be though scientific consensus that we determine whether or not the, and I love the irony here,

The world’s timekeepers will decide … to break the age-old link between their official clocks and astronomical time based on Earth’s rotation.

This is a great lesson for social construction of science, philosophy of science, the role of induction, and a good, basic lesson (if properly fleshed-out) on challenging taken-for-grantedness in our daily lives (a good follow-up too: check out how the weight of the gram has transformed in light of radiation; both are good examples about how the units of measure that “make reality” are themselves far from uniform and stable).