Use a funnel to pour vinegar into a plastic bottle
Place a balloon around the funnel and fill it with 2 teaspoons of baking soda. (This next photo is real life…tears from our toddler because he didn’t want to wait his turn…)
Cover the top of the bottle with your balloon. Lift your balloon up so that the baking soda drops down into the vinegar. Watch as the balloon fills with air!