Resource to Explore the Nature of Science
These baking soda ice cubes look like they would be an awesome experiment I would like to share with the children. As it says in the post, you can freeze the vinegar instead of the baking soda, and also get a cool reaction, I could certainly suggest trying both of these methods to the children.
I would probably show the children what happens to ice cubes first, and we could discuss the reaction between the vinegar and baking soda. We could then go through the process of making the cubes (different shapes wold be cool). Further investigation could involve using water straight out of the tap, or boiled water to see whether they produce different outcomes, or other baking goodies, like baking powder, flour, sugar and salt to see what happens when we add vinegar to them.