When I was in teacher-training, the latest, greatest curriculum design was called scope and sequence. The premise is curriculum as a spiral. Let's use American History as an example. In kindergarten, you introduce the concept at the kindergarten level--probably in the context of Pilgrims and Thanksgiving. The unit is short and sweet in accordance with the capabilities of an average five-year-old. This is the tight end of the spiral.
In first grade, you do a unit on American History again, revisiting the Pilgrims and Thanksgiving to catch anyone who didn't get it in kindergarten and expanding the scope of your exploration of the subject to a first grade level--let's say George Washington and Ben Franklin.
In second grade, you do another unit on American History, starting with the Pilgrims and Thanksgiving and providing greater context for George Washington and Ben Franklin by discussing the Declaration of Independence on a second grade level.
In third grade, well, you get the idea...
It's all very logical, isn't it? All the pieces fit together into a whole, there is allowance for children who didn't catch on to the concepts the year before to catch up--perfect!
Now imagine the gifted child in the scope and sequence classroom. The Pilgrims set her brain on fire with curiosity, so she goes to the library and reads everything she can on the Pilgrims and the American colonies. Fabulous, very exciting.
Then she goes to first grade, and they do the Pilgrims again, and she says, "Oh, I remember this." She's already learned about George Washington and Ben Franklin and King George III and the Declaration of Independence, so she tunes the lesson out.
Then she gets to second grade, and she's beginning to forget the details of what she learned in kindergarten but the curriculum still hasn't caught up with what she knows. She tunes out again.
Then she goes to thrid grade, and fourth, and so on. Every year it's the damn colonists--again! And history, which she used to love, now bores her.
I know whereof I speak. I was in my senior year in high school before my social studies/history classes ever got beyond the "powdered wig" stage. I hate 18th Century America with a passion. And since I am a historian by nature, this hatred is a direct result of my school experiences.
When choosing schools for gifted children, beware of scope and sequence.