You’ll need 1 plastic bottle, 1 measuring cup, 1 funnel, baking soda, ½ cup vinegar, 1 balloon and adult supervision. Start by pouring the vinegar into the bottle. Then, use your funnel to ﬁll the balloon halfway with baking soda. Carefully place the lips of the balloon over the neck of the bottle. Lift the balloon so that the baking soda mixes with the vinegar. Watch it ﬁzz! The baking soda and vinegar mix together to create an acid-base reaction, releasing gas into the balloon!