Chemical changes are changes substances undergo when they become new or different substances. For example, the fireworks we see on the 4th of July are actually metals such as magnesium and copper that change chemically as they light up the night skies with their fantastic colors. To identify a chemical change look for observable signs such as color change, bubbling and fizzing, light production, smoke, and presence of heat.

To experience chemical change you will need a candle and a match. First put on your safety glasses then light your candle. What evidence of chemical change can you observe? Write down 4 observations.
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Side note: What did you observe happened to the wax that dripped down the side of your candle? Do you think this wax changed chemically or physically? Did the wax actually change chemically or did it just physically change form when it melted and resolidified? It actually changed physically. First the candle melted when the wax changed from liquid to solid and then the wax froze when it changed from liquid to solid. (If you do not have access to a candle and match for this activity, drag your mouse over the link to view a quicktime movie of a candle burning - Close the new window it opens in to return to this page.)