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

Evidence of Physical Changes

Students will observe and describe physical changes, such as changes in state, shape, or size, without forming new substances.

• Ontario Curriculum Expectations
• 5-PS1-3

About This Topic

Physical changes alter the state, shape, or size of matter without creating new substances. In Grade 5, students observe evidence like ice melting into water, sugar dissolving in tea, or clay molded into shapes. These examples build on the particle model of matter, where particles rearrange but retain their identity. Key investigations include differentiating physical changes from chemical ones through observable properties, such as reversibility and lack of new substances formed.

This topic aligns with Ontario's matter and energy strand, fostering skills in evidence-based reasoning and prediction. Students analyze dissolving as a physical process by recovering solute through evaporation, countering the idea of disappearance. They predict freezing outcomes, noting water's expansion, which connects to density and particle spacing. These activities reinforce scientific practices like questioning and data recording.

Active learning shines here because students directly manipulate materials to gather evidence. Experiments with everyday items make particle theory observable, while group predictions and discussions clarify distinctions between change types, boosting retention and confidence.

Key Questions

1. Differentiate between a physical change and a chemical change using observable evidence.
2. Analyze how dissolving sugar in water is a physical change, not a disappearance.
3. Predict the outcome of freezing water based on its physical properties.

Learning Objectives

• Classify observed changes as physical or chemical based on whether a new substance is formed.
• Analyze the process of dissolving a solid in a liquid as a physical change by describing particle behavior.
• Compare and contrast the properties of water in its solid, liquid, and gaseous states.
• Predict the effect of temperature changes on the state of common substances like water and butter.

Before You Start

Introduction to Matter

Why: Students need a basic understanding of what matter is and that it has properties before they can observe changes to it.

States of Matter

Why: Understanding the characteristics of solids, liquids, and gases is fundamental to observing and describing changes in state.

Key Vocabulary

Physical Change	A change in the form or appearance of a substance, such as its size, shape, or state, but not its chemical composition. No new substance is created.
Chemical Change	A change where a new substance with different properties is formed. Evidence often includes color change, gas production, or heat release.
State of Matter	The distinct forms that matter can take, such as solid, liquid, or gas, determined by the arrangement and movement of its particles.
Dissolving	The process where a solute (like sugar) spreads evenly throughout a solvent (like water) to form a solution. The solute particles are still present.

Watch Out for These Misconceptions

Common Misconception

Dissolving sugar makes it disappear forever.

What to Teach Instead

Evaporation recovers the sugar crystals, proving particles spread out but remain unchanged. Hands-on evaporation demos let students see recovery, shifting their view through direct evidence and peer sharing.

Common Misconception

Any visible change is chemical.

What to Teach Instead

Physical changes lack new properties like gas production or colour shifts. Station activities expose multiple examples, helping students categorize via checklists and group debates.

Common Misconception

Freezing water creates a new substance.

What to Teach Instead

Ice melts back to water, showing same particles in new arrangement. Prediction charts before freezing, followed by melting tests, build accurate mental models.

Active Learning Ideas

Stations Rotation: Change Stations

Prepare stations for melting (ice cubes), dissolving (salt in water), shaping (playdough), and tearing (paper). Students rotate in groups, record before-and-after observations, and note if the substance changes identity. Debrief as a class to classify changes.

45 min·Small Groups

Dissolving Challenge: Pairs

Pairs test sugar, salt, and sand in equal water volumes, stirring at same rate. They measure time to dissolve and evaporate samples to recover solids. Discuss why some dissolve and others do not.

30 min·Pairs

Freezing Predictions: Whole Class

Fill trays with water, coloured water, and objects like clay balls. Students predict size and state changes after freezing overnight. Observe and measure next day, comparing to predictions.

50 min·Whole Class

Reversibility Hunt: Individual

Students list 5 physical changes from home, predict reversal methods, and test one like bending wire. Share findings in pairs.

20 min·Individual

Real-World Connections

• Bakers observe physical changes constantly when they mix ingredients, knead dough, or shape cookies. Understanding that these are physical changes allows them to predict how the dough will behave when heated, without creating entirely new compounds during the mixing phase.
• Ice cream makers use their knowledge of physical changes to freeze liquid cream and sugar mixtures into a solid state. They control temperature to achieve the desired texture, understanding that the water and fat molecules are rearranging, not chemically transforming.

Assessment Ideas

Quick Check

Present students with a list of scenarios (e.g., tearing paper, burning wood, freezing water, rusting iron). Ask them to circle the physical changes and put a star next to the chemical changes, justifying their choices with one sentence for each.

Exit Ticket

Provide students with a small cup of water and a spoonful of salt. Ask them to observe the dissolving process. On their exit ticket, they should write two sentences describing what they observed and explain why this is a physical change, not a chemical one.

Discussion Prompt

Ask students: 'Imagine you are a sculptor working with clay. How is your work similar to and different from a chef freezing water to make ice cubes?' Guide the discussion to focus on changes in shape and state versus changes in substance.

Frequently Asked Questions

How to differentiate physical and chemical changes in Grade 5?

Focus on evidence: physical changes are often reversible with same substance properties, like melting or dissolving. Use simple tests, such as evaporation for solutions or reforming shapes. Class charts comparing examples, like torn paper versus burned paper, solidify distinctions through visual and discussion-based sorting.

What activities demonstrate dissolving as physical change?

Sugar cube dissolving races or saltwater evaporation jars work well. Students time dissolution, then boil off water to retrieve crystals, observing no new substance forms. This sequence, paired with particle diagrams, clarifies solution formation and builds evidence skills over 2-3 lessons.

How can active learning help teach physical changes?

Hands-on stations with melting ice, dissolving salts, and molding clay give direct sensory evidence of particle rearrangement. Group rotations encourage observation sharing, while prediction-melting cycles reinforce reversibility. These methods make abstract ideas concrete, improve engagement, and reduce misconceptions through trial and peer correction.

Why predict freezing outcomes for physical properties?

Predictions reveal misconceptions about contraction; water expands due to particle spacing. Tray experiments with measurements before and after freezing provide data for claims. Follow-up melting confirms sameness, linking to curriculum expectations on states of matter and scientific inquiry.

From the Blog

25+ SEL Classroom Activities: A K-12 Guide to Inclusive Social and Emotional Learning

Explore 25+ research-backed SEL classroom activities for K-12, covering all 5 CASEL competencies, inclusive strategies, and cross-subject integration.