I've done this with the 3rd grade in the past but I feel the 2nd grade is totally ready to handle it, plus it's so much fun. I brought in a piece of a birch tree branch that feel down in my back yard to show and talk about how the Native Americans would use the bark to make their canoes waterproof. The bark is interesting to look at too. Using recycled paper towel tubes the students made their own birch canoes and people to put inside. The whole scene was completed the next week with a 3D pattern teepee. Some of the students got ambitious and made water and campfires.