OFFICIAL27 Why does the professor describe how chinampas were made?

[00:00.00]NARRATOR:Listen to part of a conversation between a student and the professor of his history of technology class.[00:06.49]MALE STUDENT: Would it be OK to focus on something related to agriculture?[00:10.78]FEMALE PROFESSOR: Sure, farming technology is fine, as long as it's premodern. [00:15.71]But this isn't a long paper, so you're gonna need to pick a specific area of premodern agriculture, like, um, irrigation...or food crops of ancient Greece...[00:28.30]MALE STUDENT: I'm actually interested in hydroponics.[00:30.60]FEMALE PROFESSOR: Hydroponics...growing plants in water instead of soil...[00:36.57]MALE STUDENT: Well, not in pure water–in water that has the proper mix of nutrients.[00:40.71]FEMALE PROFESSOR: O-OK, but ...is it a premodern technology? [00:44.70] I mean, hydroponics isn't really my specialty, but from the research I've read, we're talking the nineteenth century...maybe the seventeenth century, if you really stretch it.[00:56.72]MALE STUDENT: Oh? But the Aztec civilization back in the thirteenth century in "basically where Mexico City is today ". An article I read said the Aztecs were using hydroponics in something they called...I've got the word right here...um...Chinampas.
[01:12.84]FEMALE PROFESSOR: Chinampas–the so-called floating gardens...[01:17.63]MALE STUDENT: Exactly! So, yeah, the chinampas.... The article said, very clearly, these floating gardens are proof that the Aztecs invented hydroponic farming.[01:26.89]FEMALE PROFESSOR: Well, chinampas are artificial islands, built up in shallow lakes–[01:32.86]islands made from packed earth and weeds, and, uh, material from the bottom of the lake. [01:38.50]They may have appeared to be floating in the water, but in fact they reach all the way to the bottom of the lake. [01:45.32]So the primary growing medium–that the plants draw nutrients from–is actually soil, not water.[01:53.74]MALE STUDENT: So the article was wrong about that. [01:56.22]Too bad. It seemed like a great topic, but I guess...[01:59.91]FEMALE PROFESSOR: Wait a minute. [02:00.91]Uh, just because chinampas were not technically hydroponic ...doesn't mean this couldn't be an appropriate topic for your paper. [02:10.91]Chinampas were still a great premodern technological achievement. [02:15.45]I mean, they enabled the Aztecs to grow plenty of food ...in an area without much available farmland.
[02:22.28]MALE STUDENT: But I wonder why the author wrote that chinampas were hydroponic?[02:26.17]FEMALE PROFESSOR: Well, it's pretty common for writers to generalize–say, use a term like "hydroponics" to describe other types of agriculture. [02:35.73]Personally, I'd never say "hydroponic" except for plants growing in liquid. [02:40.91]The crops on chinampas definitely benefitted from the water surrounding them, [02:45.73] but [doubt, questioning] hydroponic?
[02:48.22]MALE STUDENT: OK, so I'll go with chinampas, but leave out the "hydroponics" part ...
[02:52.85]FEMALE PROFESSOR: Actually, there's an important lesson here: we should pay attention to what happened in history, but also how historical events are presented. [03:03.90] Why, for example, would writers use a word like "hydroponics" so casually?[03:10.32]MALE STUDENT: I guess 'cuz it's a popular topic people wanna read about?[03:13.65]FEMALE PROFESSOR: Or ...to help modern-day readers understand something historical, maybe these writers think a familiar frame of reference is needed.[03:22.77]MALE STUDENT: Well, that article was in a popular magazine, not a scholarly journal for historians.[03:28.29]FEMALE PROFESSOR: OK, but historians sometimes do the same thing.[03:31.93]MALE STUDENT: So I guess then that all historians might not describe chinampas in quite the same way either.[03:37.01]FEMALE PROFESSOR: Good point. Why not look into that too? ... [03:39.95]and include it along with your description and analysis.