fair or foul ?

Question
we have a 8 and under team and the question is, if the fielder in straddling the foul line when fielding a ground ball that starts in fair and ends up rolling foul when caught, Is this considered a foul ball. when one foot is in and one foot is out. Can you guide me to the rule book a well please, thanks?

Answer
I sounds like you are talking about how to determine whether a ball is fair or foul prior to it passing 1st or 3rd base.

Where the fielder is when the ball is first touched has absolutely no bearing on whether the ball is fair or foul.  If the ball is on or over fair territory when first touched, fair ball.  If the ball is on or over foul territory when first touched, foul ball.

Once it passes the bases at the corners things are a bit different.  The ball is fair or foul based on what territory it is over when it first touches a player if the ball hasn't yet touched the ground.  If the ball hits the ground, pass the corners, before touching a player the ball is fair or foul based on which territory it first touches the ground in.

I don't know which rule book you would like me to site, but it doesn't matter as this would be universal to all rule sets.  Plus, I don't have my books with me at work.  I am only certifed with NFHS.

If somebody starts arguing this with, start betting lunch on it!