We did three different experiments with a softdrink bottle.
Here is Sofia, Ella and Victoria. They put a piece of plastic at the top of an empty bottle and put down the bottle in warm water to see what happens. They succeeded! The piece of plastic started to tremble.
Markus and Fredrik put a balloon on an empty bottle and put it in the warm water. It was exciting! The balloon inflated.
Together, we found out what happens when you mix vinegar and baking soda. We poured some vinegar (we used a variant containing 24% acetic acid) in a bottle. Then we put baking soda in a balloon, which came on the bottle. When the baking soda fell into the vinegar, carbon dioxide was formed and the balloon was inflated.