We used the top part of a bottle as our funnel to pour the vinegar into the bottle. We also used this funnel to fill the balloon with baking soda. Mike slipped the balloon over the neck of the bottle and Carter lifted the balloon to let the baking soda fall into the bottle.
Carter was surprised to see what happened! The balloon started inflating all by itself.
The best part of doing these experiments.....Carter's reaction. Priceless.