THE ACRE

The acre is an unit to measure the area, used in the agriculture of several countries. Depending on the country and the time, it corresponds to several surfaces, generally between 0,4 and 0,5  hectares.

It is traditionally defined as the area of one chain by one furlong (66 by 660 feet), which is exactly equal to 10 square chains, ​or ¹⁄₆₄₀ of a square mile, and approximately 4.047 m².

The acre was roughly the quantity of land tillable by a yoke of oxen in a day. This explains the acre as the area of a rectangle with sides of length one chain and one furlong. A long, narrow strip of land is more efective to plough than a square plot, since the plough does not have to be turned so often. The word "furlong" itself derives from the fact that it is one furrow long (Acre, s.f.).

The acre is commonly used in a number of current and former Commonwealth countries, like United Kingdom, the United States and Canada. In addition, almost all countries of the former British Empire used it, such as Ghana, India or the Caribean islands where agricultural lands is measured in acres.

I understand that it would difficult to Primary students. Those ones who show problems to manage our system will not like the acre because it is more complex. However, it could implement a little activity (third cycle) in which they could go to the playground and measure it with their feet. They would compose small groups, and while one is measuring a side, another could measure the opposite side, and so on. At the end, they would write down the number of feet and, in the classroom, they could present their results with all their classmates. Thus they operate through estimations, not by means of an accurate system, dealing with other measurement models.

References:

Acre (s.f). En Wikipedia. Recuperado el 17 de marzo de 2019 de https://en.wikipedia.org/wiki/Acre