A chemical change occurs when a substance or substances change to make a new substance or substances. Chemical change occurs through chemical reactions. Chemical reactions are normally not easily reversible because the atoms of a substance are rearranged. A physical change occurs when a substance or substances combine, but the result does not change the original substances. Some physical changes are easier to reverse than others, such as dissolving salt in water.
In this activity, students will create a T Chart that illustrates examples of chemical and physical changes. To extend this activity, ask students to describe what happens during the change and why it's an example of a physical or chemical change.
| Examples of Chemical Change | Examples of Physical Change |
|---|---|
| Cooking an Egg | Melting Ice |
| A Rusting Nail | A Bottle of Soda Freezing |
| Burning a Match | Crumpling Paper into a Ball |
| Milk Turning Sour | Butter Melting on Toast |
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Student Instructions
Identify and illustrate different types of chemical and physical changes.
Capture attention by performing a quick, safe demonstration—like mixing vinegar and baking soda—at the start of the lesson. Visuals and excitement help students grasp the concept of chemical changes before diving into the activity.
Ask students what they think will happen before you combine the substances. Encourage predictions to activate prior knowledge and get students thinking critically about chemical and physical changes.
Organize students into small groups to discuss what they observed during the demonstration. Peer discussions help solidify understanding and allow students to share their ideas about why a change is chemical or physical.
Refer back to the demonstration when students complete their T-Charts. Linking hands-on experiences to the assignment makes the learning more meaningful and memorable.
Chemical changes create new substances and are usually hard to reverse, while physical changes alter the form or appearance of a substance but do not create something new and are often reversible.
Common classroom examples include cooking an egg (chemical change), melting ice (physical change), burning a match (chemical change), and crumpling paper (physical change).
Use a T-chart for students to sort and illustrate examples, then discuss the evidence for each type of change, such as new substances formed or reversibility.
Chemical changes involve rearranging atoms to form new substances, making it difficult or impossible to return to the original substances by simple means.
Signs include color change, formation of a gas, temperature change, precipitate formation, or new odor, indicating a chemical reaction has taken place.