Observing the sleep patterns of children never ceases to amuse (and confound) me.
From the time Isaac was very small, he virtually refused to fall asleep when he was being held. He had to be laying in his bed away from any commotion in order to doze off. Otherwise, everything going on around him was far too interesting to allow his eyes to close.
We attempted to violate this principle just a couple of times, once when he was about fifteen months old. Out and about touring the city of Chicago, we reasoned that surely he would reach a point of such exhaustion that he would sleep for a while in the stroller.
It was not to be. We strolled at the museum, along the lakefront, through the busy downtown. He wouldn't so much as lay down - all of the sights were so engaging. He didn't nap all day long, and even as we walked back to our car (past his bedtime, in the dark) he would not allow sleep to come.
My daughter is not that way. We took a long but lovely walk after lunch today, Isaac riding his bike and me pushing Abby in her stroller. At 12:30, she was asleep in the stroller (before her normal naptime) regardless of the hot sun and constant chatter between myself and Isaac. At 12:36, I woke her up.
I laid the kids down for naps at 1pm, thinking of course my poor little dear was still so exhausted. But she must not be. It's 1:53pm and she's still babbling away in her crib.
Kids are nothing like a good science experiment: instead of being repeatable, results generally confound me.