How Much Shampoo does it take...

to fill a bathtub with bubbles? I went to check on the sloshing I could hear going on in the bathroom. My little one was floating in a foamy sea of bubbles. I was thinking "Where did she get bubble bath?" I was pretty sure we had used all of the bubble bath within a day of my purchasing it. So I asked my dh, who was supposed to be "giving baths" to the kids, where did we get the bubble bath? He smiled and said "shampoo". So that is why I go through a bottle of shampoo a week. I was wondering how four little heads, two with very short hair could use so much shampoo. I guess I'll have to figure out which is cheaper, shampoo or bubble bath. Or I will have to take over the bathing supervisor job.