One of the things I love about the What Do You See/Hear? books by Bill Martin Jr. and Eric Carle (the series includes Brown Bear, Brown Bear, What Do You See?, Polar Bear, Polar Bear, What Do You Hear?, Panda Bear, Panda Bear, What Do You See? and Baby Bear, Baby Bear, What Do You See?) is how easy it is to come up with projects and ideas to extend each book into your every day life or classroom!
After going on a What Do You See/Hear? Walk with your family or classroom, why not come home and write and illustrate your very own What Do You See/Hear? book? It will give your child a chance to use their memory to recall what they saw when they were out on their walk, and they will get to be the authors and illustrators of their very own book, which you can then read as a family (or classroom) over and over again!
After going on your walk (which can be to the park, at the zoo, around the grocery store...anything goes!) come home (or back to your classroom) and sit down to talk about what you remember seeing! Have each child (and the adults too if they'd like) color pictures of the different things they remember seeing (or smelling, hearing, etc.) and then write out your story as a group. "Molly, Molly, what do you see? I see a butterfly smiling at me!" "Mikey, Mikey, what do you hear? I hear and elephant trumpeting in my ear!" The children can write the lines on their own if they are old enough, or you can give them some help if they need it. This is also an opportunity to work on rhyming words with your children. (Though it is not a requirement to rhyme on every page. It can be hard to find a good rhyme for the question "What do you smell?" or "What do you touch?")
Once all the pictures are done you can laminate them if you have access and ability to do so, but if not that's OK! You can bind the pictures together using a binder and hold punch, stapler, yarn, etc. Once done you have a wonderful book that can not only act as a reminder to a special day you had as a family (or class), but is also something that will bring pride to your children, as they have now illustrated and written a book all by themselves!
Have fun and happy reading!