I recently attended an art course for children - lots of inspiration for observing nature and working with natural materials - it was great. One thing I will definitely use in my role as a teaching assistant is creating collages without glue - yes it's a temporary work of art. Most children like to create pieces of art independently - and supplies are always accessible to them. However, left to their own devices they often choose not to use glue, but yards of sticky tape, hog all the best resources and be quite wasteful unsupervised. So the concept of creating a piece of art that doesn't involve glue may appeal to all.
Although they won't be able to take their artwork home with them - this can be solved by taking a photo of their work and putting it on display. This also works well with children (boys!) who like to use construction toys, such as lego and blocks. Smaller models may be kept on a shelf for a little while to admire - but eventually it has to go back in the box to be reused. A photo stays forever.
Which links to this:
My own little glue less (unsewn) temporary collage for my daughter's birthday. My husband had a trip to Japan, so we paid for her to accompanying him. As a textile/fashion student I hoped the trip would be inspirational to her and sent her this for her birthday.