My first science unit was Matter. One of our NGSS standards is conducting an experiment to determine whether the mixing of two or more substances results in a new substances. I filled the balloon and attached to a bottle with vinegar. They made observations on the liquid and the solid in the balloon. They did not know what the substances were. We shook the baking soda into the bottle and instantly the balloons filled with the gas, carbon dioxide. My students could identify that it was a chemical change.
I love to watch the reactions on their faces!!!! This is one of my favorite labs of the year and so easy to set up.
I had them fill out the lab sheet after we completed the experiment.
This is part of my Matter Unit available on TPT