word choice - Difference between 学生・生徒・児童

As the title says^^　I think 生徒 is for elementary school, what about the other two?

Answer

Students are 学生 for most of their educational life:

kindergarten      幼稚園児(ようちえん･じ)

elementary school 小学生(しょうがく･せい)
middle school     中学生(ちゅうがく･せい)
high school       高校生(こうこう･せい)
university         大学生(だいがく･せい)
graduate school   大学院生(だいがくいん･せい), 博士課程の学生(はくし･かていのがくせい)

I would always pass myself off as はかせかていのメンバー (member of the doctorate course). I was never corrected on this.

The other two act as group descriptors, rather than something a student would refer itself as:

児童  "children", up to including elemenatry school

生徒  "a member of the body of students", middle school and up

According to Japanese animated television series, Japanese spend what is called their life in school and then transform into a rigid plant-like lifeform. Hence there are a lot of other terms describing that growth phase, such as:

• [弟子]{でし} (novice of some craftsman)


• [在校生]{ざいこうせい} (enrolled high school student)


• [在学生]{ざいがくせい} (enrolled student)


• [書生]{しょせい} (scholarly student)


• [学僕]{がくぼく} (student learning under and working for a teacher)