A TORNADO in a JAR
It worked, though not the first time around 🙂
Fill two thirds of a small mason jar with baking soda, a tbsp of dishwashing liquid and a tbsp of vinegar. If you add some food coloring, it will certainly be more impressive.
Close the lid well and start shaking the jar until you make a regular tornado… It didn’t work immediately for us, so don’t despair if you don’t succeed at first… wait a little and shake the jar again…