Where's the Evidence?

Guiding Question:  What are some signs that a chemical reaction has taken place? 


Hypothesis: I think every substance will have a other reaction. Some will maybe change the color, other will be cold or hot.


List of the Materials used: 
-Baking soda 
-sugar 
-copper sulfate
-sodium carbonate
-zinc
-calcium chloride
-aluminium foil
-starch and iodine

Analysis of your results: I thought that some of them are going to explode, change color or over float.Some of them were bubbling a time and then it stops. One of them over float and after that nothing happened again. And several changed color but not instantly but after a time.