Kid K'nex Education is a great engineering tool to have in your library. The pieces are bigger, so they don't hurt smaller fingers, and the students can create all kinds of fun creatures using this set. I have my second grade graders and even my third graders build with these, and they LOVE them. I think these go well beyond the preschool age group. The set we purchased from Amazon (click on the red link above) comes with 131 pieces, so having 2-3 sets in your classroom or library is ideal.
Where to begin? How do we use these in library? To start with, we read about different animals, insects, and critters. A couple of great books to consider reading aloud are the following ideas and suggestions: (Click on the book title for the read aloud).
Fur, Feather, Fin: All of Us are Kin
Now is a great time to discuss habitats. What sort of animals and bugs live in a desert habitat? Woodland habitat? Rainforest habitat? What types of foods do they eat? What kind of adaptations do they require to survive? What is the food chain? If you have a subscription to PebbleGo, this is a great time for students to access the databases and get some really good background information.