Discovering Physical and Chemical Changes
What do you already know about physical and chemical changes?
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What do you already know about physical and chemical changes?
Discovering Physical and Chemical Changes
Learning Objective
At the end of the lesson you will be able to explain the difference between physical and chemical changes, and give everyday examples of each.
What Is a Physical Change?
A physical change is when matter changes its appearance but not its chemical structure. No new substances form.
What Is a Chemical Change?
A chemical change creates a new substance. Old materials change into something new and often cannot change back easily.
Physical vs Chemical Changes
Chemical Change
Physical Change
Makes one or more new substances. Often irreversible. Example: Burning paper.
Does not make a new substance. Often reversible. Example: Folding paper.
Example: Physical Change
Cutting an apple only changes its shape. It’s still an apple and the change can be reversed by putting pieces together.
Example: Chemical Change
Iron nail rusting forms new substances. The rust cannot easily turn back into the original nail.
Signs of Chemical Change
Look for colour changes, gas or bubbles, a new smell, or heat during a chemical change.
Can You Reverse the Change?
Physical changes can often be reversed, like freezing and melting water. Chemical changes are usually permanent.
Time to Reflect
Think of an example of each type of change from your own life. Which signs helped you decide if it was physical or chemical?
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.
