I'm a newbie, so I'm open to advice. I'm trying to understand how google works because I'm not sure what is happening with some of my pages.

I made 6 pages and am logging what happens so I can understand things as I learn. I chose very very low search keywords, so I can see how they rank quickly. This was 2 weeks ago.

In the 2 weeks, what happened was all the 6 got into the top 10 of their keywords (again, these are super super low search keywords, I intentionally am trying them so I can see how the rankings work, not anything worthwhile I you want to make any money, just for learning right now).

But right now a strange thing happened, 3 of them are still climbing in the top 10, but the other 3 fell all the way to position 900+ or so.

Can anyone explain what is happening?

The 6 sites are the same, 6 different keywords, but pretty much same layout, though different keyword density, some higher than others. So not sure if that affects it.

I've heard of google dance. Is this google dance or is it telling me that google doesn't like something in the other 3 (which I'll have to figure out and fix)? Also, if it is google dance, how can you tell if the movement is google dance or not, are there any signs, and how long does that usually last?

Hope someone can explain things to a beginner.