That is an awesome video.  As a kid, I was always confused why Europe and Asia were not one continent and really confused if Russia was in Europe or Asia, since adults seemed to disagree (as a child, no adult I asked could really say why they classified it the way they did).  I hadn't thought about this in a long time, but this sociological explanation makes sense and is really helpful.

It’s a cultural construct, with some geological rationale, but not enough to rationalize the seven that we recognize.

Just who is this "we" that recognize it? ;)

I'm surprised that the video didn't mention the Olympic flag, the interlinking circles meant to represent the five human-inhabited continents with recognized nation-states (i.e., Antarctica isn't included). Of course, it's based on a non-English, European definition of continent: America, Europe, Asia, Africa, and Australia.

I had the "how many continents are there" argument with my girlfriend almost two years ago, and that caused me to look into the question a little bit: http://umlud.blogspot.com/2010/04/just-how-many-continents-are-there.html

Memorizing the names and locations of the "seven" continents is just a schoolhouse exercise.

OH MY GOD, THANKS!!! I'm so tired of explaining to americans that south americans do view America as a single continent and this is why it's a bit annoying hear USA being referred as America.

This is funny, I have gone over this discussion with so many american friends since I moved here! I'm from Perú, and what they teach us is that there are FIVE continents: America (yes, one continent!), Africa, Oceania, Europe and Asia. That's it! ;). If I'm not wrong, this is what you learn in any country in Latin America.

We should all just go back to Pangaea! :D

The continents are OBVIOUSLY America and Afroeurasia. Antarctica is a frozen archipelago and Australia is an island. Two  continents: so much easier. (Again: I joke.)

... remind me again, though, why these arbitrary boundaries are so important? Since we know that they aren't purely physical delineations (at least not any that follow a single rule), then the only justification is for a social construction of them (and reinforcement of that construction through historical use). However, if they had been constructed in a different way, then our perceptions of them would be likewise different (see the video's point as well as Lala's elsewhere in the comments about USA vs. America for Spanish-speakers).

It's clear - at least to me - that we could go with anything from a two continent model (only America and Afroeurasia) to a fifteen continent model (the geologists' tectonic plates definition). As - elsewhere in the comments - LarryW pointed out (in one of the few times that I'm likely to fully agree with his comment), listing them is merely a schoolhouse exercise. I would say that regardless of what framework we use to understand the extent of the physical landmasses of the world, we should not focus so heavily on them, but should, instead, be teaching kids (and learning for ourselves) WHAT is going on in these regions and HOW that is important in regional and supra-regional ways.

In Australia, while we usually call ourselves the "island continent" (BL Tasmania), we also sometimes use terms like "Australiasia" or "Oceania" too. Oceania definitely refers to Aus, NZ and various pacific island nations (often PNG too) while Australiasia, I think, is a shorthand for Australia and NZ.

Being an English speaking country, we usually get taught that there is North and South America, although sometimes it is referred to as the Americas. Russia is a major grey area. India, Sri Lanka, Bangladesh, Pakistan and Nepal (and sometimes Afghanistan and the Maldives too) are referred to as the Sub Continent, although as a part of Asia.

Even the definition varies. I'm pretty sure that I was taught that Arctica (Artctis? Arctic? see, the english langiage doesn't even use its name all that often!) was a continent, and only later on learned that it's a sort of exception since there's no actual land underneath all that ice. I suppose it's for the same reason that maps are centered differently, you just think about something less when it's far away.

Justifying counting the two Americas, and Africa and Eurasia as separate continents is as easy as sticking an "or joined only with a narrow isthmus" into the definition. Separating Eurasia, on the other hand, is pretty much only doable on the social construction level.

Geologists don't equate continents with tectonic plates. Geologists divide the Earth's crust into two *types of material*, continental (lighter and older stuff with lots of granite) and oceanic (thinner and newer stuff with lots of basalt). A given tectonic plate can be made up of one or both of those types of crust.

The video contains a fun bit of exoticism as well with the description of the dangers of the Amazon awaiting the person aiming to walk the length of the Americas. South America can actually be traversed relatively easily by a number of highways, notably the Pan-American Highway that runs down the Andes. The tricky stretch is the Darien Gap in eastern Panama, where a combination of cost and indigenous resistance have prevented road-building.

Also, the Antarctica-as-archipelago thing is slightly tricky -- the weight of the ice has pushed lots of parts of Antarctica below sea level, but if the ice were removed, isostatic rebound would eventually lift them up. On the other hand, the melting of all that ice would re-flood portions of antarctica -- but also of other landmasses!

I remember reading a Wikipedia article on the Continents (as one does) and learning that the issue was not clear cut.

Fun and informative video.

I'm surprised nobody's mentioned Martin Lewis' great book "The Myth of Continents".