You will need: Bendable straws, *metal BBs, hot glue, cereal/cracker box, a bottle cap, pencil, and plain paper
What to do: Design your run on a piece of paper. Next, use hot glue to add straws to the cardboard box according to your design, then put the BBs into the straw to go through the run and observe how well they go down. Make any changes needed. Add a bottle cap to the end of your run to collect the BBs as they come down.
*Use BBs that fit in the straw easily and run smoothly through it.