Science · Grade 5

Active learning ideas

Measuring Matter: Mass and Volume

Active learning helps students grasp the abstract concepts of mass and volume by connecting them to tangible observations. When students manipulate materials directly, they build a concrete understanding of conservation laws and changes in matter. This hands-on approach also builds observation skills, which are essential for identifying chemical changes versus physical ones.

• Ontario Curriculum Expectations
• 5-PS1-2

• 25–40 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Gallery Walk
• 30 min · Small Groups

Gallery Walk: Change Detectives

Place photos or real-life examples of changes (rusty nail, sliced apple, melted chocolate, baked bread) around the room. Students move in groups to identify each as physical or chemical, noting the specific evidence they see. They leave sticky notes with their reasoning for other groups to review.

Explain why mass remains constant even when a substance changes state.

Facilitation Tip

During the Gallery Walk, position yourself near stations where students struggle to classify changes as physical or chemical, and ask guiding questions like, 'What evidence supports your classification?'

What to look for

Provide students with a small rock and a graduated cylinder with water. Ask them to record the initial water level, submerge the rock, and record the final water level. Then, have them calculate the rock's volume using the water displacement method.

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

Activity 02

• Inquiry Circle
• 40 min · Small Groups

Inquiry Circle: The Disappearing Mass

Students mix vinegar and baking soda in an open cup on a scale, then repeat the experiment inside a sealed bag. They compare the mass readings and discuss in groups why the mass seemed to disappear in the first trial but stayed the same in the second, discovering the role of gas.

Compare methods for measuring the volume of regular and irregular objects.

Facilitation Tip

For The Disappearing Mass, remind students to zero the balance scale before measuring and to record all data in a table to track changes in mass.

What to look for

On a small slip of paper, ask students to write down the formula for calculating the volume of a rectangular prism (length x width x height) and explain in one sentence why mass does not change when ice melts into water.

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Activity 03

• Formal Debate
• 25 min · Pairs

Formal Debate: Reversible vs. Irreversible

Assign students different scenarios, such as dissolving salt in water or frying an egg. Students must argue whether the change can be undone and what evidence supports their claim. This encourages the use of scientific vocabulary like 'solubility' and 'chemical reaction.'

Predict how the density of an object affects its buoyancy in water.

Facilitation Tip

In the Structured Debate, assign roles such as 'scientist,' 'environmentalist,' and 'industrialist' to ensure all perspectives are represented and debated respectfully.

What to look for

Pose the question: 'Imagine you have a block of wood and a block of metal that are the same size. Which do you think has more mass? Why?' Facilitate a discussion about how different materials have different densities.

• Analyze
• Evaluate
• Create
• Self-Management
• Decision-Making

A few notes on teaching this unit

Teachers should emphasize observation first, classification second. Start with simple physical changes that students can easily reverse, like melting ice or dissolving salt, before introducing chemical changes like burning paper. Use real-world examples, such as rusting or baking, to connect classroom learning to everyday experiences. Avoid rushing to definitions; instead, let students develop criteria for change through guided exploration.

By the end of these activities, students will confidently measure mass and volume, classify changes in matter, and explain why the total mass remains constant in a closed system. They will use evidence such as gas production, color change, or heat release to justify their classifications of physical and chemical changes.

---

Watch Out for These Misconceptions

• During the Gallery Walk, watch for students who classify dissolving sugar in water as a chemical change because the sugar 'disappears.'

  Use the 'evaporation test' at this station by allowing students to observe the sugar recrystallizing after the water evaporates. Ask them to revisit their classification and discuss whether the process can be reversed.

• During Collaborative Investigation: The Disappearing Mass, watch for students who assume the mass is lost when a substance burns or evaporates.

  Provide sealed containers or use a balance scale to show that the total mass remains the same before and after the reaction. Have students discuss why the mass appears to change when substances escape into the air.

---

Methods used in this brief

• Gallery Walk
• Inquiry Circle
• Formal Debate