search on google . Read this What is Google's Sandbox and this Sandbox effect - Wikipedia, the free encyclopedia or this http://www.google.com/support/forum/...4fd3fa41&hl=en
this should help you

What is google sandbox - Webmaster Central Help

Search on Google and then if you got some problem in understanding then ask the question it is the best way of learning for new in SEO.

Here are some useful articles:
How to Avoid Google Sandbox?
Google's Sandbox Still Exists: Exemplified by Grader.com | SEOmoz

Don't just post. Google it. Google is your best friend.

The Google Sandbox Effect is a theory used to explain why newly-registered domains or domains with frequent ownership changes rank poorly in Google Search Engine Results Pages (SERPS).

I also have heard much about the Google sand box and sites getting their rankings dropped and getting stuck in the Google Sand box.I have never truly understood what it is. Can anyone please explain?

Google does not acknowledge sandbox but I think it exists. Google puts new domains in sandbox so they don't rank high in search results. If after a year, Google finds those sites are good enough to be ranked, then they are taken out of sandbox.

The Google Sandbox is the place where Unicorns and Big Foots go to defecate. As far as seo goes there is no such thing. Sorry to disappoint.

Google sand box defines the active age of domain, if domain changes that it will affect on the Google ranking.