I like to show examples of real sculptures (it could be anything.) We talk about the differences between a painting and a sculpture. We define a sculpture in Kindergarten as "a piece of art that you can walk around." They never forget this because I literally have them walk around the sculptures. Then we get started on our foam sculptures.
You'll need foam (packaging from boxes works well) (I'm sure marshmallows will work also), white paper, white glue, and toothpicks.
We build the sculptures from the base up (I encourage them to make a wide base for stability) using toothpicks and foam. Not much instruction is needed (or even helpful) because this is a project about experimentation! Try this project and I swear you won't be able to hear a pin drop in your room! Perfect for the end of the year madness.