Floating and Sinking

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Overview

This is a two-day practical Science investigation centred around the concept of buoyancy and linked to the "World Around Us" topic of the Titanic. Pupils will collaboratively design, build, and test recyclable-material boats to understand what makes objects float or sink. Throughout both lessons, pupils will develop their scientific enquiry skills, strengthen teamwork, and broaden their understanding of materials and forces, in alignment with the Northern Ireland Primary Curriculum.

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Curriculum Links

Northern Ireland Curriculum Area:
The World Around Us – Interdependence, Place, Change Over Time, Movement and Energy

KS2 Attainment Targets (Year 5):

• Develop an understanding of the properties of materials and forces.
• Use practical and scientific methods, processes and skills.
• Ask relevant questions and use different types of scientific enquiries.
• Make predictions, carry out fair tests and record results.

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Learning Objectives

By the end of the two lessons, pupils will be able to:

• Investigate and understand the concept of buoyancy.
• Link historical events (Titanic) to scientific principles.
• Collaboratively design and construct a model boat using recyclable materials.
• Conduct a fair test and record results accurately.
• Reflect on how materials and shapes affect buoyancy.

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📘 Lesson One: Build a Boat

Duration: 60 mins
Theme Focus: Designing Boats from Recyclable Materials

Resources Needed

• Clean recyclable materials (e.g. plastic bottles, juice cartons, tin foil, cling film, bottle caps)
• Scissors, masking tape, glue guns (supervised), hole punchers
• Design Worksheets (to sketch plan and list materials)
• World map, print of Titanic ship blueprints
• Images of Titanic and various boats
• Whiteboard, markers, and safety scissors
• Timer for each task (visible to class)

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Lesson Breakdown

1. Starter Activity – Titanic Link (10 mins)

• Begin with a questioning circle:
  “Why did the Titanic sink?”
  Pupils discuss in pairs, then share ideas.
• Show images of the Titanic and explain its historical sinking with a focus on buoyancy and compartment flooding.
• Briefly introduce the concept of buoyancy – the ability of an object to float in water based on its shape and the materials used.

2. Group Work & Design (15 mins)

• Organise pupils into mixed-ability groups of 2–3.
• Each group gets a Design Sheet, where they sketch an idea and list materials they plan to use.
• Encourage consideration of:
  • How to balance the boat
  • What materials float
  • How to make sides high enough to keep water out

3. Build the Boat (30 mins)

• Children construct their boats using selected materials.
• Adults circulate to question and challenge thinking:
  • “How will you stop it from tipping over?”
  • “Why did you choose that material?”
• Ensure safe use of scissors and glue guns.
• Each group names their boat and writes a hypothesis:
  “We think our boat will hold ___ coins before sinking.”

4. Clean Up & Reflection (5 mins)

• Tidy workspace.
• Groups share a 30-second explanation of their boat's features.

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Assessment for Learning

• Teacher observation during discussions and group work
• Quality of group design sheets
• Appropriate use of materials
• Evidence of prediction and reasoning

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Differentiation

• Provide scaffolded design sheets for pupils with SEND or lower literacy levels.
• Extension challenge for early finishers:
  Design a second boat using only one type of material.

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🌊 Lesson Two: Buoyancy Challenge

Duration: 60 mins
Theme Focus: Scientific Testing of Boat Designs

Resources Needed

• Water trays (set up outside)
• Group boats from previous lesson
• 1p coins (pre-counted in tubs)
• Clipboards and Record Tables
• Stopwatch/timers
• Towels and spare clothes (for spillages)
• Revisit Titanic diagrams

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Lesson Breakdown

1. Recap & Prediction (10 mins)

• Review boats as a class; remind pupils of the Titanic and its compartments.
• Discuss what buoyancy means – key vocabulary on the board: float, density, water resistance, gravity.
• Each group writes their prediction again:
  “We think our boat will hold ___ 1p coins before it sinks.”

2. Testing Time! (30 mins)

• Move outdoors to the water testing station.
• In rotation, each group tests their boat:
  • Teacher/TA and one student add 1p coins until the boat sinks or stops.
  • Other group members record the results.
• Encourage fairness:
  • Coins dropped in gently
  • Placed evenly to prevent tipping

3. Results Table & Discussion (10 mins)

• Back inside, pupils complete the results table:

  Boat Name	Did it Sink?	Max No. of 1p Coins	Comments

• What worked well? What didn’t? Consider boat shapes and materials.

4. Class Discussion & Titanic Link (10 mins)

• Class discussion:
  “Which boat performed best? Why?”
  “What would have happened if the Titanic had used different material or design?”
• Tie back to science: different materials have different densities, and some designs displace water better.

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Assessment for Learning

• Ability to explain test results
• Group cooperation during the test
• Accuracy in recording results
• Vocabulary use during reflection

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Differentiation

• Visual support cards explaining the word buoyancy.
• Adult support for groups needing help with counting or recording coins.

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Extension Opportunities

• Create a mini science fair: pupils present their boat and findings to another class.
• Write a diary entry from the perspective of a boat designer in 1912, exploring what they would change post-Titanic.

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Cross-Curricular Links

• History: Exploration of Titanic timeline and significant events.
• Art and Design: Creative boat construction using household materials.
• Mathematics: Counting, estimating and recording data.
• Literacy: Hypotheses, explanations, and reflections.

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Teacher Reflection Notes

Encourage discussion around trial and error, linked to inventors who learn from failures. Remind children that even the Titanic was once believed unsinkable, reinforcing the value of critical thinking and resilience in Science.

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Wow Factor: Pupils are applying real-world scientific principles in a historical context that ties directly into their topic work, while actively engaging in hands-on experimentation. This promotes deep understanding through creativity, collaboration, and practical problem-solving.