Floating and Sinking

Curriculum Area and Level

Curriculum: Scottish Curriculum for Excellence
Level: First Level
Experience and Outcome:

"Through exploring properties and sources of materials, I can choose appropriate materials to solve practical challenges." SCN 1-15a

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Learning Intentions

By the end of the lesson, pupils will:

• Understand that some materials float while others sink.
• Explore the properties of materials to predict their buoyancy.
• Develop observation and reasoning skills through hands-on experimentation.

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Success Criteria

Pupils will:

• Make predictions about whether objects will float or sink.
• Conduct a practical experiment to test their predictions.
• Record and discuss their findings using simple scientific language.

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Lesson Structure (75 minutes)

1. Introduction (15 minutes) – The Magic Story of the Floating Boat

• Gather students on the carpet and tell a short, engaging story about a tiny mouse who wants to build a boat to cross a river.
• Ask the pupils: Do you think all objects float? Why do some sink?
• Show an empty plastic bottle and a stone. Ask: What do you think will happen if I drop these in water?
• Take quick verbal predictions from the class, encouraging reasoning (e.g. “I think the bottle floats because it’s light”).

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2. Hands-on Experiment (35 minutes) – The Floating Test

Materials (per group of 4-5 pupils)

• Large clear containers filled with water
• A selection of objects:
  • Wooden block
  • Spoon (plastic & metal)
  • Small rubber ball
  • Lego brick
  • Coin
  • Sponge
  • Foil ball
  • Cork

Experiment Steps

1. Pupils work in small groups with a set of materials.
2. Each group makes predictions by sorting objects into a "Float" or "Sink" tray before testing.
3. One at a time, pupils gently place an object into the water, observing carefully.
4. They update their predictions based on actual outcomes.
5. Discussion within the group: Were there any surprises? Why do we think some objects float while others sink?

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3. Extension Challenge (15 minutes) – Build a Floating Raft

• Give each group a piece of foil, some straws, and tape.
• Their challenge: Build a small raft that can hold a small toy without sinking!
• Pupils test their rafts in water and make adjustments if necessary.
• Ask: What materials worked best? Why?

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4. Plenary (10 minutes) – Reflection and Science Talk

• Gather pupils and review key findings together.
• Ask: Did objects float or sink the way you expected? What materials were the best for floating?
• Highlight that shape, weight, and material all affect floating.
• End with the question: If you had to design a boat for the tiny mouse from the story, what would you build it from?

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Assessment Opportunities

• Observation: Are pupils making reasonable predictions? Are they communicating their ideas clearly?
• Participation: Engagement in group discussions and hands-on activities.
• Verbal Reflections: Can pupils explain their reasoning for why they think objects float or sink?

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Resources and Preparation

• Large water containers (at least 5 for group work)
• Variety of small objects with different materials
• Aluminium foil, drinking straws, and tape for raft-building
• Sorting trays or simple template worksheets for predictions

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Teacher’s WOW Challenge 🌟

Surprise pupils by making something unexpected float! Before the lesson, coat an orange in its peel and drop it into the water. Then peel it and place it back in – it sinks! Ask pupils why they think the skin helps it to float!

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Differentiation

• Support: Work in mixed-ability groups; use visuals and physical prompts to reinforce understanding.
• Challenge: Encourage higher-order thinking by asking pupils to sort floating items by size vs. shape to see if patterns develop.

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Cross-Curricular Links

• Literacy: Retelling the story of the mouse and the boat using key scientific words.
• Numeracy: Counting and recording how many objects sank vs. floated.
• Technology: Designing rafts and boats using materials creatively.

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This hands-on, explorative lesson will spark curiosity in young learners while building foundational science skills. Teachers will love the tangible engagement, and pupils will walk away excited about floating and sinking! 🚢✨