Physical and Chemical Properties of Matter

Active learning works well for physical and chemical properties because students often confuse the two or assume all changes alter the substance. Hands-on stations let them directly observe and manipulate materials, building clear distinctions between traits that stay the same and those that signal new substances are forming.

• Grade 7
• Science
• 4 activities
• 30 min–50 min

Learning Objectives

1. Classify substances as having distinct physical properties such as density, melting point, or solubility.
2. Compare and contrast physical and chemical properties, providing specific examples for each.
3. Analyze how observing physical properties aids in the identification of unknown substances.
4. Predict potential hazards associated with a substance's chemical properties, such as flammability or reactivity.
5. Explain the difference between a physical change and a chemical change based on property observation.

Stations Rotation

⏱ 50 min·Small Groups

Stations Rotation: Physical Property Stations

Prepare stations for density (layer liquids by pouring carefully), melting point (heat paraffin and chocolate on hot plates), solubility (test salt and oil in water), and magnetism (test everyday objects). Groups rotate every 10 minutes, recording data on charts. Debrief with class sharing of patterns.

Prepare & details

Differentiate between a physical property and a chemical property with examples.

Facilitation Tip: During the Physical Property Stations, circulate with a timer to keep groups focused and ensure they complete each station before moving on.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Stations Rotation

⏱ 30 min·Pairs

Prediction Challenge: Chemical Properties

Show safe demos like steel wool in vinegar (reactivity) or paper near flame (flammability). Students predict outcomes in pairs, observe, then classify as chemical. Discuss why new substances form, linking to property definitions.

Prepare & details

Analyze how observing physical properties can help identify an unknown substance.

Facilitation Tip: For the Prediction Challenge, provide only the substances and ask students to predict what will happen before any reactions occur.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Stations Rotation

⏱ 40 min·Small Groups

Unknown Substance ID: Property Testing

Provide coded samples (e.g., sand, salt, iron filings). Students test physical properties: mass for density, solubility in water, response to magnet. Groups hypothesize identities and present evidence to class.

Prepare & details

Predict how a substance's chemical properties might influence its safe handling.

Facilitation Tip: In the Unknown Substance ID activity, have students record all test results in a table before making their final identification to reinforce methodical observation.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Gallery Walk

⏱ 35 min·Pairs

Gallery Walk: Property Cards

Distribute cards with examples like 'rusting iron' or 'boiling water'. Pairs sort into physical or chemical categories on posters. Whole class gallery walk allows voting and corrections with justifications.

Prepare & details

Differentiate between a physical property and a chemical property with examples.

Facilitation Tip: During the Sorting Gallery Walk, assign each pair a starting point so students move in an orderly fashion and all cards receive equal attention.

Setup: Wall space or tables arranged around room perimeter

Materials: Large paper/poster boards, Markers, Sticky notes for feedback

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

Teaching This Topic

Start with safe, relatable examples so students see how properties explain everyday phenomena. Avoid overemphasizing memorization of terms; instead, ask students to explain why a change is physical or chemical in their own words. Research shows students grasp these concepts better when they manipulate materials and discuss observations in small groups rather than listening to lectures.

What to Expect

Students will confidently label properties as physical or chemical and justify their choices using evidence from their observations. Their discussions and written work will show they recognize that chemical changes produce new substances while physical changes do not.

Watch Out for These Misconceptions

Common Misconception

During the Physical Property Stations, watch for students who assume melting or dissolving means a chemical change happened.

What to Teach Instead

Remind students to look for evidence that the original substance can be recovered, such as evaporating water to get back the salt they dissolved. Ask them to point out where the salt is still present in its original form.

Common Misconception

During the Prediction Challenge, watch for students who describe chemical properties using only appearance words like colour or texture.

What to Teach Instead

Have students revisit their predictions after the reactions occur and note that colour change alone isn’t enough; the fizzing or new substance formation signals a chemical property.

Common Misconception

During the Sorting Gallery Walk, watch for students who claim certain common items lack chemical properties.

What to Teach Instead

Direct them to test items like steel wool or baking soda with vinegar, then ask why these everyday materials behave differently when reacted.

Assessment Ideas

Quick Check

After the Physical Property Stations, present students with a list of properties and ask them to label each as physical or chemical and justify two examples using observations from the stations.

Exit Ticket

During the Unknown Substance ID activity, collect students’ data tables and final identifications to check if they correctly identified the primary property tested and labeled it as physical or chemical.

Discussion Prompt

After the Sorting Gallery Walk, pose a scenario about an unlabelled solid and ask students to share which physical properties they would test first and why, and which chemical test they would avoid due to safety concerns.

Extensions & Scaffolding

• Challenge students to design a new station that tests both physical and chemical properties of a common household item, then have peers rotate to it.
• For students who struggle, provide a partially completed data table for the Unknown Substance ID activity with some tests already recorded.
• Deeper exploration: Ask students to research how forensic scientists use physical and chemical properties to identify unknown substances at crime scenes.

Key Vocabulary

Physical Property	A characteristic of a substance that can be observed or measured without changing the substance's chemical identity. Examples include color, density, and melting point.
Chemical Property	A characteristic of a substance that describes its potential to undergo a chemical change or reaction by virtue of its composition. Examples include flammability and reactivity.
Density	The mass of a substance per unit volume, often expressed in grams per cubic centimeter (g/cm³). It helps determine if a substance will float or sink in another substance.
Flammability	A chemical property that describes a substance's ability to burn or ignite easily. It indicates how readily a material will combust in the presence of an oxidant, usually oxygen.
Reactivity	A chemical property that describes how readily a substance combines or reacts with other substances. High reactivity means a substance easily undergoes chemical changes.