SciGen Teacher Dashboard
Unit M3
Concentrating on Pink Lemonade
Categories of Chemicals and Mixtures
Condensation and Evaporation
Describing Physical and Chemical Change
The Three Little Chemists and the Big Bad Wolf
Conversation: Describing Physical and Chemical Change
Duration: Approximately 45 minutes
This activity focuses on how to discern and describe the difference between physical and chemical change. First the students consider the difference between a bending nail and a rusting nail. They go on to look again at phase change. Burning is offered as an example of chemical change, and other common indicators of chemical change are mentioned. Finally, students try their hands at classifying familiar examples of change into physical and chemical.
LEARNING OBJECTIVE
Students will compare physical and chemical change.
Students will consider whether phase change is a physical or chemical change.
Students will classify familiar changes as physical or chemical change.
Teacher Tune-ups
Teaching Notes
ACTIVITY OVERVIEW
Physical and chemical change: notice the difference (15 minutes)
The bending nail is an example of a physical change. Students can see that there is no change in the particles (the smallest parts) of the nail as a result of bending. Their position changes, but not their chemical identity: they are still all iron atoms.
Ask students what they think happens when a nail is exposed to moisture. This is no longer a physical change but a chemical change. The second slide explains a chemical reaction.
Ask students to contrast the types of change.
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Explain to students that there has been what we call a chemical reaction–the iron from the original nail, oxygen in the air, and water are like the “ingredients” of rust. However, instead of ingredients, we use the more scientific vocabulary “reactants.”
Phases changes (5 minutes)
Show the animation of solid, liquid and gas at the particulate level and ask students to identify them and to discuss their properties.
Show second panel by clicking "reveal."
Ask students to consider if there is physical or chemical change when water is heated and cooled in this manner.
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physical
What about burning? (10 minutes)
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What about burning? Do you think that is a physical or chemical change?
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Mention to students that light and heat are often sign of chemical change. Common indicators of chemical change are:
Categorize change (15 minutes)
Do this section as a class discussion, in groups, or as an individual assessment.
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