Here is a student sheet to accompany an engaging activity to reinforce the concepts of force and motion.
Students will make a marshmallow shooter from cups and balloons.
Use a plastic cup with the bottom removed. Take a balloon, tie a knot in the end that you would blow up, and snip the other end with scissors. Stretch the open end around the plastic cup. Place items inside the cup, pull back on the balloon knot, and release to shoot the marshmallows.
I'd recommend a Google search on how to make the shooters if you are still not sure. You may also want to make them ahead of time for the littlest learners to cut back on time.
(*Pro tip: recycled applesauce cups are perfect for a sturdy shooter)