A physical reaction is when you change the appearance of a substance and can return it to its original state.
First I placed the rusty metal on the ground and then set up the Mentos to drop into the Diet Coke. Even through my kids have seen the Mentos reaction before, they did not mind doing it again.
Which one is a physical reaction? Which one is the chemical reaction? My main question was, “which one is going to give me a new substance?” (Now I am trying to trick them some by using a physical reaction that looks like a chemical reaction)
Since I cannot make the rust return to being a metal, I have a chemical reaction. If I could catch the CO2, I could return it to the soda, and only a physical reaction has happened.
Now since my chemical reaction is a little boring, watching metal rust, I decided to make smoke bombs. You need stump removal and sugar to make the smoke bomb. Stump removal can be found in the lawn and garden section near the pesticides.
Taking 1 1/2 cups of stump remover to 1 cup of sugar and in a pan over low heat you want to caramelize the sugar. Once you have the dark brown liquid pour it into a blob on aluminum foil to cool. Once it cools, it will harden and then can be removed from the foil.
We placed ours on a stepping-stone and made sure no flammable items (leaves/grass) were near the smoke bomb. We lit it with a lighter and watched the reaction. It was awesome! I got to be the cool mom for the day.