Explore: What is the Difference between a Physical Change and a Chemical Change?

The rusting of the iron metal on a truck is a chemical change that occurs when the iron is exposed to air and water.

The making of burnt toast from bread is a chemical change to the bread caused by heat and oxygen.

Water undergoes a physical change when snow or ice melts in the spring.

Chopping vegetables for dinner is a physical change to the shape of the vegetables!


Questions you should ask yourself when trying to decide if some change is chemical or physical include the following:

  • Did it change colour?
  • Did it produce gas? (shown by bubbles or fizzing)
  • Did it produce a precipitate (solid from mixing two liquids)?
  • Did it produce heat or light?
  • Is it reversible?
  • Did it make a new substance?

This last question is the key difference between a physical and a chemical change. A chemical change always produces a new substance that is different from what you started with. A physical change changes how your original substance looks; it does not make something new.

You will be asking all these questions as you explore various kinds of physical changes and chemical changes to decide for yourself: Can you tell the difference?

Try This!

Read the following story about Cory Change-Up and His Really Bad Day. Notice all the changes that occur throughout the story. (They are underlined.)

As you read through the story, highlight all physical changes in green and all chemical changes in red.

Ask yourself:

  • Did it change colour?
  • Did it produce gas? (shown by bubbles or fizzing)
  • Did it produce a precipitate?
  • Did it produce heat or light?
  • Is it reversible?
  • Did it make a new substance?

If you answer “Yes” to one or more of these questions, then it is likely a chemical change.



Corey Change-up

To highlight select the colour you would like and then click on the underlined sentence



Cory Change-Up was having a REALLY bad day. The first thing he noticed when he woke up that morning was that all the rain that had fallen the night before had frozen into ice. Dreading the slippery sidewalks, he rushed to get dressed for work and ripped a hole in his favourite shirt. After burning his toast and boiling water for his tea, he sat down to eat breakfast. He added sugar to his tea and when he stirred it so it would dissolve, it spilled all over his shirt that already had a hole! He took some antacid to help his upset stomach from the burnt toast before heading off to work. Cory noticed rust was starting to form on his bike and decided it would be safer to walk today. Hopefully, his day would get better!

  Check Your Answers

Check your answers for the activity below


Cory Change-Up was having a REALLY bad day. The first thing he noticed when he woke up that morning was that all the rain that had fallen the night before had frozen into ice. Dreading the slippery sidewalks, he rushed to get dressed for work and ripped a hole in his favourite shirt. After burning his toast and boiling water for his tea, he sat down to eat breakfast. He added sugar to his tea and when he stirred it so it would dissolve, it spilled all over his shirt that already had a hole! He took some antacid to help his upset stomach from the burnt toast before heading off to work. Cory noticed rust was starting to form on his bike and decided it would be safer to walk today. Hopefully, his day would get better!