Understanding Matter Deeply

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Curriculum Links

NSW Science Stage 4 – Year 7 (Aligned with the NESA Syllabus)
Content Strand: Physical World
Sub-Strand: PW1 – Physical properties of materials
Outcomes:

• SC4-16PW: Describes the action of unbalanced forces in everyday situations
• SC4-7PW: Describes factors that influence the transfer of energy in systems
• SC4-13MW: Identifies the physical and chemical properties of substances and how these determine their use

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Lesson Title:

Mass, Volume, Density & Buoyancy: The Science Behind Floating

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Duration: 60 Minutes

Class Size: 25 Year 7 Students
Lesson Type: Theory and Demonstration with Hands-On Element

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WALT (We Are Learning To):

• Understand how mass and volume relate to the concept of density
• Use the displacement method to measure volume
• Explain the relationship between density and buoyancy
• Predict whether an object will float or sink based on its density

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Success Criteria:

By the end of the lesson, students will be able to: ✔ Define mass, volume, density, displacement and buoyancy
✔ Accurately calculate the density of an object using the formula
✔ Describe, in their own words, why some objects float while others sink
✔ Link real-life examples to scientific theory (e.g. ships floating, icebergs)
✔ Participate in a class investigation using displacement and density formulas

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Materials Required:

• Digital slides (with clear, dyslexia-friendly fonts – e.g., OpenDyslexic or Arial 14pt+)
• Whiteboard and markers
• Science journals or worksheets
• Water container (large, clear measuring jug or a displacement can)
• Measuring scales (digital kitchen scales are ideal)
• Solid objects of different materials (e.g., rubber ball, metal bolt, wooden block, plastic cube, candle)
• Graduated cylinders
• Stopwatches
• Paper towels

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Lesson Breakdown:

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⏱️ 0 – 10 mins: Warm-Up & Review

Teacher Script:
“Good morning everyone! Today, we’re going to explore something you experience every time you toss something in water. This lesson is all about why some things float, others sink, and how we can calculate the science behind it. Let’s explore the secrets of mass, volume, density and something very cool called buoyancy.”

Activity:
Quick “Guess the Outcome” game:

• Show students five objects. Ask: “Will this object sink or float?”
• Do not reveal the answer yet – this will be the hypothesis they'll test later.

Differentiation Tip: Use visual objects and physical handling for EAL/D students and students with learning difficulties.

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⏱️ 10 – 20 mins: Explicit Teaching with Real-Life Examples

Key Concepts to Cover:

Term	Definition	Everyday Example
Mass	How much matter is in an object (measured in grams or kilograms)	A watermelon vs. an apple
Volume	The amount of space an object takes up (measured in cm³ or mL)	A balloon inflated vs. deflated
Density	How tightly matter is packed (Density = Mass ÷ Volume)	Honey vs. oil
Displacement	The volume of water pushed out when an object is submerged	Water rising in a bath
Buoyancy	The upward force that water exerts on an object	A life jacket keeping someone afloat

Teacher Script:
"Let's think about a bath. When you step in, the water rises. That's displacement in action. Now, imagine two blocks the same size: one made of wood and another of metal. They have the same volume, but very different masses – which means different densities! This determines whether they sink or float."

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⏱️ 20 – 35 mins: Interactive Experiment: Displacement & Density

Group Work (Groups of 4–5):
Each group gets:

• One object
• Measuring jug or displacement can
• Digital scale
• Calculator

Step-by-step Instructions:

1. Measure the mass of the object (in grams) using the scale
2. Fill the jug with water and record the initial volume
3. Submerge the object, measure the change in water level = volume (in mL)
4. Use the formula:
   Density = Mass ÷ Volume
5. Record if the object floated or sank
6. Discuss results: Did the calculated density predict what happened?

Teacher Support:

• Float between groups asking critical questions: “What does a bigger volume but lighter mass tell us?”
  “Why does something with lower density than water always float?”

Targeted Support for Struggling Students:

• Visual aids of formulas
• QR code to digital calculator tool
• Sentence starters for explanations

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⏱️ 35 – 45 mins: Class Discussion: Apply & Reflect

Key Questions:

• “Why do massive ships made of steel float, while tiny metal nuts sink?”
• “What role does shape play in flotation?”
• “What does a submarine do to its density to sink or rise?”

Teacher Script:
“The Titanic was an enormous ship made of metal. But it floated because of its shape and the air inside. When it filled with water, its density increased – and it began to sink.”

Use images of ships/submarines/icebergs to tie concepts together visually.

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⏱️ 45 – 55 mins: Quick Quiz & Extension Discussion

Quick Quiz (5 mins): (Display questions on the board)

1. What is the formula for density?
2. If an object has a mass of 60g and a volume of 30cm³, what is its density?
3. Will an object with a density of 1.2 g/cm³ float in water?

Extension Task (Advanced Learners):

• Research and share one material that is heavier than water but floats. Why?
• Design a boat using only aluminium foil and tape – which design holds the most marbles before sinking?

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⏱️ 55 – 60 mins: Wrap-up & Exit Ticket

Exit Ticket Prompt:
“Write one sentence explaining why some things float and others sink, using the word density."

Collect the tickets as they leave.

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Differentiation Strategies

Learner Type	Strategy
Dyslexic Students	Use dyslexia-friendly fonts on handouts/slides. Include visuals. Provide oral instructions and sentence scaffolding.
EAL/D Students	Pair with peer buddy. Use gesture, visuals, and simplified vocabulary. Include bilingual translations if available.
Advanced Learners	Encourage boat design challenge, introduce variable density concepts, or link to advanced fluids like mercury.
Visual Learners	Emphasise diagrams, animated video clips, and live demonstrations.
Kinesthetic Learners	Engage fully in hands-on activity and predictions. Provide movement-based tasks.

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Assessment Opportunities

• Observation during group activity and experiment
• Quick quiz for formative assessment
• Exit ticket for comprehension review
• Ongoing questioning and class discussion participation

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Optional Homework Task

Design a poster or short digital presentation about "How Density Affects Life Around Us" – include examples like icebergs, oil spills, or floating animals.

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Reflection (Post-Lesson for Teacher):

• Were students able to make the link between density and buoyancy?
• Were group roles effective?
• Did students show engagement through prediction and curiosity?

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Wow Factor Tips:

• Use a floating candle experiment to show density changing as wax melts
• Make it a narrative: "You are scientists trying to save a sunken treasure – understand displacement and buoyancy to retrieve it!"

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Next Lesson Preview:
Explore how gases can displace liquids and how density affects the environment – balloon science!

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Prepared by: [Your Name or School]
Date Prepared: [Insert Date]
Stage 4, Year 7 – NSW Science

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