Science · Grade 3

Active learning ideas

Properties of Gases

Active learning lets students directly observe gases, which are invisible and hard to conceptualize. Hands-on experiments make abstract properties concrete and memorable, helping students connect evidence to ideas about matter.

• Ontario Curriculum Expectations
• 2-PS1-1

• 20–35 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Hundred Languages
• 20 min · Whole Class

Whole Class Demo: Balloon Squeeze

Inflate a balloon inside a clear plastic bottle by attaching it to the mouth, then squeeze the bottle to observe air compression and expansion. Have students predict and record changes in balloon size. Discuss how gas fills the space and pushes back.

Explain how we know that air is matter, even though we cannot see it.

Facilitation Tip

During Balloon Squeeze, have students feel the resistance before and after inflation to emphasize air's force.

What to look for

Present students with a sealed plastic bag and an unsealed one. Ask: 'Which bag contains more matter? How do you know?' Then, ask: 'How could you prove that the air inside the sealed bag takes up space?'

• Understand
• Apply
• Create
• Self-Awareness
• Self-Management
• Social Awareness

Activity 02

• Hundred Languages
• 30 min · Small Groups

Small Groups: Bubble Jar Test

Fill jars halfway with water, cover with plastic wrap, and push down to trap air, then release to see bubbles rise. Groups measure bubble height and compare to empty jars. Record observations on charts to show gas volume.

Compare the behavior of gas particles to those of liquids and solids.

Facilitation Tip

For Bubble Jar Test, ask groups to predict how many breaths will fill the jar, then compare predictions to results.

What to look for

On a sticky note, have students draw a picture showing one property of a gas. Below the drawing, they should write one sentence explaining the property shown, using at least one vocabulary word from the lesson.

• Understand
• Apply
• Create
• Self-Awareness
• Self-Management
• Social Awareness

Activity 03

• Hundred Languages
• 25 min · Pairs

Pairs: Straw Displacement

Partners blow through a straw into a glass of water to create bubbles, then measure water level change before and after. Predict if gas adds volume, observe displacement. Share findings in a class gallery walk.

Design an experiment to demonstrate that gas takes up space.

Facilitation Tip

In Straw Displacement, circulate to check that students seal the straw opening correctly to trap air.

What to look for

Pose the question: 'Imagine you have a solid block, a bottle of water, and an empty balloon. How would you show that the empty balloon is not truly empty, but filled with gas?' Facilitate a class discussion comparing student ideas.

• Understand
• Apply
• Create
• Self-Awareness
• Self-Management
• Social Awareness

Activity 04

• Hundred Languages
• 35 min · Individual

Individual: Design Challenge

Students design and test a way to prove air takes space, using household items like cups and paper. Draw plans, test, and present evidence. Teacher circulates to guide safe trials.

Explain how we know that air is matter, even though we cannot see it.

Facilitation Tip

For Design Challenge, provide a rubric with clear criteria for testing gas expansion and volume.

What to look for

Present students with a sealed plastic bag and an unsealed one. Ask: 'Which bag contains more matter? How do you know?' Then, ask: 'How could you prove that the air inside the sealed bag takes up space?'

• Understand
• Apply
• Create
• Self-Awareness
• Self-Management
• Social Awareness

A few notes on teaching this unit

Start with simple, visible gas demonstrations to anchor abstract ideas. Focus on one property at a time so students build understanding step-by-step. Avoid overloading with vocabulary early; let concepts emerge from observations before naming them.

Students will explain that gases expand to fill containers, have mass and volume, and move differently than solids or liquids. They will use observations from activities to support these claims with evidence.

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Watch Out for These Misconceptions

• During Balloon Squeeze, watch for students who say the inflated balloon feels lighter because it contains 'nothing'.

  Have students weigh a deflated balloon and then an inflated one on a balance scale to observe the mass increase.

• During Bubble Jar Test, watch for students who think the air leaves the jar when bubbles pop.

  Ask groups to trace the path of air from their lungs to the bubbles and back, using the jar as a visual reference.

• During Straw Displacement, watch for students who confuse air bubbles in water with the water itself taking up space.

  Have pairs measure the water level before and after blowing bubbles to show the water level rises, proving air adds volume.

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Methods used in this brief

• Hundred Languages