Question 39785
Make three groups of three.
Put two of the groups on opposing scales.
IF THE TWO GROUPS BALANCE: the heavy ball is not in those two groups.
So take the remaining group; put one ball on each scale.
If they balance the heavy one is in your hand; if one
side is heavier, it is the heavy ball.
IF THE TWO GROUPS DO NOT BALANCE: the heavier ball is in the heavier
group.  Follow the procedure outlined above for the heavier of the
two groups of three.
Cheers,
Stan H.