Is Was (Deborah Freedman)

 

This is beautiful. I also loved This House, Once. The simplicity of this book would be a great conversation starter in a classroom. 

Goodreads says:

Explore the connections found in nature in this simply stunning picture book that explores the idea of change, both big and small.

This sky is
the same sky that was blue,
and now is
spilling down in drips and drops…
until rainclouds pass…

Over the course of one day, a small child experiences the way the natural world changes from sun to rain and from day to night as things transform from is to was in this breathtaking book.