1.？ Preparation materials: a clean bottle, water, vinegar, baking soda, balloon, funnel, measuring cup, etc.

2.？ Fill the bottle with water, pour it into the measuring cup and record the volume of water.

3.？ Pour a certain amount of vinegar into the bottle, which can be determined according to the size of the bottle, accounting for about one-third of the bottle volume.

4.？ Pour baking soda into the funnel and slowly pour baking soda into the bottle with the funnel. At the same time, we can observe the bubbling of liquid in the bottle, which is the release of carbon dioxide gas.

5.？ Put the balloon on the bottle mouth, gently squeeze the bottle, and observe the expansion of the balloon. It can be found that the balloon will gradually expand.

This experiment can not only understand the influence of gas produced in chemical reaction on pressure, but also experience the fun of scientific experiment.