Final answer:
Observations that indicate a chemical change include temperature changes, light given off, unexpected color changes, and formation of bubbles. Examples of chemical changes include lab reactions, combustion, and food being cooked or digested.
Step-by-step explanation:
Observations that help to indicate a chemical change include:
Temperature changes (either the temperature increases or decreases).
Light given off.
Unexpected color changes (a substance with a different color is made, rather than just mixing the original colors together).
Bubbles are formed (but the substance is not boiling-you made a substance that is a gas at the temperature of the beginning materials, instead of a liquid).
To identify a chemical reaction, we look for a chemical change. A chemical change always produces one or more types of matter that differ from the matter present before the change. Examples of chemical changes include reactions that are performed in a lab, combustion, and food being cooked, digested, or rotting. The formation of new substances with different properties is a key characteristic of a chemical change.