Dalam dua hari terakhir ini saya telah menerima beberapa email berantai dengan subject “1 ONS BUKAN 100 GRAM”, yang isinya kurang lebih menyatakan bahwa selama ini telah terjadi kesalahkaprahan dalam dunia pendidikan Indonesia sehubungan dengan penggunaan satuan pond dan ons.
Sebelum ikut menyebarluaskan email berantai tersebut, ada baiknya anda menyimak beberapa informasi berikut:
The Dutch term ons is a unit of mass that is considerably more, 100 g, a redefinition adopted with the introduction of the metric system together with a redefinition of the Dutch pond as 1 kg. (Though the ons of 100 g remains in informal usage, this pond as a kilogram has fallen by the wayside, replaced by the metric pound of 500 g adopted in other countries.)
In many countries that use the SI or metric system, the pound (or its translation, for example, the German Pfund, the French livre, or the Dutch pond) is used as an informal term for half of a kilogram, therefore for this case the pound is 500 grams. In many cases, this was an official redefinition back in the 19th century, but its use is generally no longer officially sanctioned. These replaced hundreds of older pounds, for example, one of around 459 to 460 grams in Spain, Portugal, and Latin America; 498.1 g in Norway; and several different ones in what is now Germany. In the case of the Dutch pond, this was officially redefined as 1 kg, with an ounce of 100 g; the former has fallen out of use, and if the pound is used today it is likely the 500 g variety, but the 100 g ounce remains in limited use.
ons = a Dutch unit of weight or mass, now used as a metric unit equal to the hectogram (100 grams, or about 3.5274 ounces).
pond  = the Dutch pound, historically about 494 grams (1.089 English pounds). This unit was also used in the former Dutch Indies (now Indonesia) and throughout Southeast Asia. In the Netherlands, the pond has been reinterpreted now as a metric unit equal to exactly 500 grams (1.1023 pounds), like the German pfund.
Jadi kesimpulannya adalah…?