Color change is an important sign that a chemical reaction is happening. It usually means that new substances are being created. Here are a couple of examples:

• Rust Formation: When iron meets oxygen, it changes to a reddish-brown color. This shows that iron oxide, or rust, has formed.

• pH Indicator: When you add an acid to a base, it can change the color of a pH indicator. This change tells us that a reaction has taken place.

These color changes are helpful because they allow us to see the effects of the chemical reaction. They make it easier to tell if something is happening.