Exploring Our World: Scientific Inquiry and Discovery · 3rd Year

Active learning ideas

Mixing Solids and Liquids

Active learning works for this topic because mixing solids and liquids requires students to observe changes firsthand, which builds concrete understanding of dissolving and suspensions. When students test predictions with real materials, they confront misconceptions through tangible evidence rather than abstract explanations.

• NCCA Curriculum Specifications
• NCCA: Primary - Materials
• NCCA: Primary - Materials and Change

• 25–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Stations Rotation
• 45 min · Small Groups

Stations Rotation: Dissolving or Suspending?

Prepare stations with salt, sugar, sand, and chalk powder in water cups. Students predict solubility, stir for one minute, observe settling or clarity over five minutes, and sketch changes. Rotate groups every 10 minutes to test all solids.

Explain why some solids dissolve in water while others do not.

Facilitation Tip

During Station Rotation: Dissolving or Suspending?, place clear containers of water and solids at each station so students can see changes from multiple angles.

What to look for

Provide students with three small containers, each with water and a different solid (salt, sugar, sand). Ask them to observe, record predictions about dissolving, and then mix. For each, ask: 'Did the solid dissolve? How do you know?'

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

Activity 02

• Inquiry Circle
• 30 min · Pairs

Pairs: Prediction Testing

Pairs list five household solids and predict if they dissolve in water. Test two each, stir uniformly, time dissolution, and discuss why some work and others do not. Record in a shared class chart.

Compare the properties of a mixture to the properties of its original components.

Facilitation Tip

During Prediction Testing, ask pairs to write their predictions before testing to make their reasoning visible.

What to look for

On an index card, ask students to draw a simple diagram of sand mixed with water. Then, ask them to write two sentences explaining what will happen if left undisturbed and one way they could separate the sand from the water.

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

Activity 03

• Inquiry Circle
• 50 min · Small Groups

Small Groups: Separation Challenge

Mix sand and salt in water; groups design filters using coffee filters, sieves, or cloth. Test methods, evaporate remaining water to recover salt, and evaluate which separation worked best based on recovery amount.

Design a method to separate sand from water.

Facilitation Tip

During Separation Challenge, provide filter paper, magnets, and evaporation dishes so students can explore multiple separation methods.

What to look for

Pose the question: 'Imagine you are making lemonade. You add sugar, but it doesn't seem to dissolve. What are two things you could try to help the sugar dissolve?' Listen for student ideas related to stirring, temperature, or amount of water.

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

Activity 04

• Inquiry Circle
• 25 min · Whole Class

Whole Class: Property Demo

Demonstrate mixing flour and water versus sugar and water. Class observes and votes on property changes, then brainstorms real-life examples like cake batter or syrup. Chart comparisons on board.

Explain why some solids dissolve in water while others do not.

Facilitation Tip

During Property Demo, use a spoon to stir mixtures slowly so students can time how long dissolving takes for different solids.

What to look for

Provide students with three small containers, each with water and a different solid (salt, sugar, sand). Ask them to observe, record predictions about dissolving, and then mix. For each, ask: 'Did the solid dissolve? How do you know?'

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

A few notes on teaching this unit

Teach this topic by letting students work with real materials first, then introducing vocabulary and concepts to explain what they observed. Avoid rushing to definitions; instead, let students describe their observations in their own words before formalizing terms like 'solution' or 'suspension.' Research suggests hands-on mixing helps students distinguish dissolving from suspending, which is foundational for later chemistry topics.

Successful learning looks like students accurately predicting whether a solid will dissolve, explaining observations with evidence from their tests, and using vocabulary such as 'solution' or 'suspension' correctly. They should connect their observations to the idea that mixtures retain the properties of their original components.

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Watch Out for These Misconceptions

• During Station Rotation: Dissolving or Suspending?, watch for students who assume all solids will dissolve if stirred long enough. Redirect by asking them to observe the sand station closely and describe what happens to the particles over time.

  During Station Rotation: Dissolving or Suspending?, have students stir each mixture for the same amount of time, then compare clarity and particle visibility. Ask them to explain why sand particles remain visible while salt disappears.

• During Separation Challenge, watch for students who think mixtures create new substances. Redirect by asking them to separate the mixture back into its original parts using tools like filters or evaporation.

  During Separation Challenge, remind students to test if the separated solids match the original, such as tasting recovered salt to confirm it tastes the same as before mixing.

• During Property Demo, watch for students who believe dissolved solids are gone forever. Redirect by asking them to predict what will happen to the water as it evaporates.

  During Property Demo, set a small dish of saltwater aside and observe it daily, asking students to record changes and taste the recovered salt when the water is gone.

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Methods used in this brief

• Stations Rotation
• Inquiry Circle