Physical Changes vs. Chemical Changes

Contributor: Elephango Editors. Lesson ID: 11032

Discover the exciting world of physical and chemical changes! Learn how matter transforms, test your skills with fun experiments, and spot science in action all around you.

1To2Hour
categories

Physical Science

subject
Science
learning style
Kinesthetic, Visual
personality style
Lion, Beaver
Grade Level
Middle School (6-8)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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The Mystery of Mulch and Ash

Picture this: you're raking up leaves with a family member. Some get chopped into mulch, while others are tossed into a fire pit and turn into ash.

mulch and ash

  • What’s going on here?
  • Why does mulch stay wood-like, but ash becomes something entirely different?

Get ready to dive into the fascinating science of physical and chemical changes to solve this mystery.

What Are Physical and Chemical Changes?

Matter is all around you, and it’s constantly changing.

Sometimes, these changes are subtle, like ice melting. Other times, they’re dramatic, like fireworks exploding.

These changes fall into two main categories: physical changes and chemical changes.

Physical Changes

A physical change happens when matter changes in size, shape, or state, but it stays the same substance. Its chemical structure doesn’t change.

Here are some examples.

Ice melting into water is still water, just in a different form.

Cutting a piece of paper doesn’t turn it into something new—it’s still paper.

Kneading dough into different shapes doesn’t change what it is.

  • Can you think of something in your house that’s gone through a physical change?

Chemical Changes

A chemical change is a bit more dramatic. It creates a completely new substance. This happens when the molecules in matter rearrange during a reaction.

Chemical changes are often irreversible.

Here are some examples.

Burning wood creates ash and smoke, substances different from the original wood.

Rust forming on metal is a slow chemical change.

When you bake a cake, the ingredients mix and heat to become something new.

  • Can you think of a time when you saw something transform into something completely different?

Watch the video below to explore the differences between physical and chemical changes further.

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Now, go back to the mulch and ash mystery.

Mulch is a physical change because the wood was just chopped into smaller pieces—it’s still wood.

Ash is a chemical change because fire transformed the wood into something entirely new.

Head to the Got It? section for more physical and chemical changes!

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