Science · Grade 5 · The Particle Nature of Matter · Term 1

Measuring Matter: Mass and Volume

Students will learn to measure the mass and volume of different objects and substances using appropriate tools.

• Ontario Curriculum Expectations
• 5-PS1-2

About This Topic

In this topic, Ontario students explore the transformative nature of matter. They learn to distinguish between physical changes, where the substance remains the same but changes form (like ice melting), and chemical changes, where new substances with different properties are created (like wood burning into ash). This distinction is vital for understanding the world's cycles, from the water cycle to industrial manufacturing. Students look for evidence of chemical change, such as the production of gas, changes in color, or the release of heat and light.

This unit also introduces the law of conservation of mass in a simplified way, helping students realize that matter is never truly lost, even when it seems to disappear. This connects to environmental stewardship by showing that waste doesn't just 'go away.' The curriculum encourages students to consider the social and environmental impacts of chemical processes used in everyday life, such as the creation of plastics or the processing of food.

Students grasp this concept faster through structured discussion and peer explanation of their observations during experiments.

Key Questions

1. Explain why mass remains constant even when a substance changes state.
2. Compare methods for measuring the volume of regular and irregular objects.
3. Predict how the density of an object affects its buoyancy in water.

Learning Objectives

• Measure the mass of regular and irregular objects using a balance scale.
• Calculate the volume of regularly shaped objects using mathematical formulas.
• Determine the volume of irregularly shaped objects using the water displacement method.
• Compare the mass and volume of different substances to infer density.
• Explain how mass is conserved during a change of state.

Before You Start

Introduction to Measurement

Why: Students need basic familiarity with units of measurement like grams and centimeters before learning to measure mass and volume.

Properties of Objects

Why: Understanding that objects have different characteristics, such as size and weight, is foundational for measuring their mass and volume.

Key Vocabulary

Mass	The amount of matter in an object, measured in grams (g) or kilograms (kg).
Volume	The amount of space an object occupies, measured in cubic centimeters (cm³) or milliliters (mL).
Balance Scale	A tool used to compare the mass of an object to known masses.
Graduated Cylinder	A tall, cylindrical container with markings used to measure the volume of liquids or the volume of irregular solids through water displacement.
Water Displacement	A method to find the volume of an irregular object by measuring the change in water level when the object is submerged.

Watch Out for These Misconceptions

Common Misconception

Dissolving sugar in water is a chemical change because the sugar 'disappears.'

What to Teach Instead

Students often think a new substance is formed. Teachers can use the 'evaporation test' to show that the sugar is still there, just broken into tiny particles. Peer discussion about whether the process can be reversed helps students classify dissolving as a physical change.

Common Misconception

Matter is destroyed when something burns or evaporates.

What to Teach Instead

Because smoke and steam drift away, students assume the mass is gone. Using sealed containers for reactions helps students see that the total mass remains constant. Hands-on modeling of the 'closed system' is essential for correcting this view.

Active Learning Ideas

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.

30 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.

40 min·Small Groups

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.'

25 min·Pairs

Real-World Connections

• Bakers use scales to measure ingredients like flour and sugar precisely, ensuring consistent results in recipes. They also measure the volume of liquids like milk or oil.
• Shipbuilders and naval architects calculate the volume and mass of ship components to ensure stability and buoyancy in water, preventing vessels from sinking.
• Geologists use mass and volume measurements to determine the density of rocks and minerals, which helps in identifying different types of geological formations and potential resource deposits.

Assessment Ideas

Quick Check

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.

Exit Ticket

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.

Discussion Prompt

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.

Frequently Asked Questions

What are the five signs of a chemical change for Grade 5 students?

The five common signs are: a change in color, the production of an odor, a change in temperature (heat released or absorbed), the formation of bubbles (gas), and the formation of a solid (precipitate). Students should look for at least two of these to be confident a chemical change has occurred.

How can I safely demonstrate chemical changes in a classroom?

Safe demonstrations include mixing baking soda and vinegar, observing a rusted piece of steel wool, or using iodine to test for starch in food. Always emphasize safety gear like goggles and discuss how Indigenous technologies, such as tanning hides or preserving food, also rely on these chemical principles.

What is the best way to use active learning for teaching physical and chemical changes?

Predict-Observe-Explain (POE) cycles are highly effective. Before a demonstration, students predict the outcome and whether it is physical or chemical. After observing, they must explain their reasoning to a peer. This active engagement forces them to apply criteria rather than just memorizing definitions, leading to deeper retention.

How does this topic connect to the Grade 5 focus on environmental impact?

Students examine how chemical changes in industry, like burning fossil fuels or manufacturing plastics, affect the environment. They learn that because matter is conserved, the byproducts of these reactions (like CO2 or plastic waste) stay in our ecosystem, highlighting the need for sustainable practices and stewardship.