Always……ALWAYS be sure to have more than one jar of bubbles when photographing more than one child.
#1 Eager and enthusiastic anticipation of getting to play with bubbles.
#2 Happy to be blowing bubbles
#3 Having so much fun with the bubbles that the wand is not needed. Her mouth is making them just fine. 
#4 Hmmmm, not quite ready to give up the bubbles.
#5 Sharing the bubbles isn’t nearly as much fun.
So, ok these are not your typical portraits, but I think they are just priceless. Aren’t they just a moment in time of those ages of 1 and 2?