I bet you never thought you'd see a pig fly. With this activity, you can (at least a paper one!), all while learning about Newton's Third Law of Motion.
Paper pig cut-out (download and print)
Use two chairs (or similar) as anchor points for the string. Measure the distance between them, and cut the string to fit. Thread the straw onto the string, then tie off the string on both ends to the anchor points.
Cut out the printed cupid-pig, or draw your own.
Blow up the balloon and use a clothespin to keep it secure (or just hold it)
Tape the flying pig to the balloon.
Tape the balloon to the straw.
Hold it at the end of the string, with the balloon opening pointing toward the nearest anchor point. Release the balloon and see what happens!
Newton's Third Law of Motion: for every action, there is an equal and opposite reaction.
Basically, if you kick a ball, your foot is exerting force on the ball. But the ball is also exerting the same amount of force back onto your foot. Or: when air rushes out of a balloon, it pushes against the surrounding air. This is the "action force". The balloon moving forward, as a result, is the "reaction force".