Caution: somewhat complex science-y things to follow.
Have you read Madeline L'Engle's A Wrinkle in Time? You should. It's downright fantastic. Probably one of my favorite books.
I first read it in 4th grade, as part of an in-class AG assignment. The entire Time quartet is fascinating and very well-done, but this is the best. My favorite part was the explanation of the tesseract.
Of course, in the real world, a tesseract is a four dimensional cube (well, technically five, but four spatial dimensions). The best way to represent it in its true form in 3 dimensions is a cube within a cube, with lines connecting the corners of the inner cube to the corresponding corners of the outer cube.
The only true way to represent it in 3 dimensions is its net. The net of a cube is six squares forming a cross. I'm sure you've seen it before. The net of a tesseract is like that, except made out of cubes.
However, in the book, a "tesseract" is a folding of space-time in order to travel instantaneously from one place in space-time to another.
Ms. Whatsit asks Meg questions. All questions and answers are approximated quotes, as I sort of lost my copy (my cousin has had it for at least a year. I don't expect to get it back.)
What is the first dimension?
What is the second dimension?
Well, you square the line, so you get a square.
What is the third dimension?
You square the square, leaving you with a cube.
Good. And what is the fourth dimension?
Well, you'd square the cube. Um, I think it has something to do with Einstein and time..Time! I guess it would be Time.
And then we have the fifth dimension. (Which is speculated to be the thing that is waving in a light wave.)
I can't possibly explain to you how incredibly cool I found this. And still find it. And I understood it, too. Really understood it. I wrote up sheets and sheets of paper explaining it, just because I was so enamored. I tried to explain it to people in my class. They didn't get it.
**gushes for a while longer on how awesome the book is**
In 7th grade, the book was an option for our reading groups (I didn't choose it, but that's not the point.) When giving short summaries about each book, our teacher said something like "It's kind of confusing to understand, so come ask me if you have any questions."
My mental response was something akin to "WHAT?! NO IT'S NOT!" The funny thing is, I have a friend whose experience with this book is the same as mine, even though we were in totally different classes and didn't meet until a year ago.
So in the past year (mainly as a result of meeting him- he had books on the subject and let me borrow them), I've been reading a lot about current advances in physics (mainly quantum physics) and other related topics. I just started Hyperspace by Michio Kaku today, which is what made me write this post.
Basically, I love the idea of "higher" dimensions, and my love for them came from literature, and you should all go read that book if you haven't already.
Everyone with an interest in the realm of physics has a starting point. For most people, it's science fiction. Asimov, or Herbert, or Bradbury, or any of the other Big Names. For me, it was A Wrinkle in Time, even though I didn't know it was physics back then. To me, physics was gravity.
It's fascinating. Sorry for bothering you with my gushing/positive rant.