Aggregation is the relationship between the whole and a 
part. We can add/subtract some     properties in the part 
(slave) side. It won?t affect the whole part.
Best example is Car, which contains the wheels and some 
extra parts. Even though the parts are not there we can 
call it as car.
But, in the case of containment the whole part is affected 
when the part within that got affected. The human body is 
an apt example for this relationship. When the whole body 
dies the parts (heart etc) are died.