How can I copy columns from one sheet to another with VBA in Excel?

Question

I\'m trying to write a macro that copies the content of column 1 from sheet 1 to column 2 on sheet 2. This is how the module looks like but, when I run it, I get

Answer 1

Private Sub Worksheet_Change(ByVal Target As Range)
  Dim rng As Range, r As Range
  Set rng = Intersect(Target, Range("a2:a" & Rows.Count))
  If rng Is Nothing Then Exit Sub
    For Each r In rng
      If Not IsEmpty(r.Value) Then
        r.Copy Destination:=Sheets("sheet2").Range("a2")
      End If
    Next
  Set rng = Nothing
End Sub