How do I design a database to store changes over time?

table kid
    int pkey(id)
    text name

table weight
    date when
    int kidid fkey(kid.id)
    int weight
    int pkey(id)

Child Table
-----------
ID (Generated) (PK)
Name


WeightTable
-----------
ID (Generated) (PK)
Date
Weight
ChildID (FK)