Week Two
Subject: Basic Science
Class: Primary Three
Week of the Third Term: 2nd Week
Topic: Floatation on Water
Subtopic: Objects that float on water vs. those that sink, Importance of floatation on water in technology
Objectives
At the end of the lesson, pupils should be able to:
- Differentiate between objects that float on water and those that sink.
- Identify three objects that float on water.
- Explain the importance of floatation on water in transportation and technology.
Entry Behaviour
Pupils should already know that certain materials, such as balloons and paper, can float in air. They should also be familiar with the concept of water as a liquid.
Instructional Materials
- Plastic spoon, iron spoon, and other small objects (e.g., cork, stone) for demonstrations
- Visual aids showing boats, ships, and other floating objects
- Chart with examples of floating and non-floating objects
Reference Materials
- Ijiyemi, C. (2016). Foundations of Sci. & Tech for Primary School Book 3. Lagos: Metropolitan Publishers.
- Oyinlola, M., Rahaman, B., & Ezeume, I. (2015). Basic Science and Technology for Primary School Book 3 (BEC Edition). Lagos: Spectrum Book Limited.
Content
Objects That Float on Water vs. Those That Sink
Some objects float on water, while others sink. Whether an object floats or sinks depends on its weight and shape compared to the weight of the water it displaces.
- Objects That Float: These objects are usually lighter than the amount of water they push aside. Common examples include:
- Wood
- Plastic bottles
- Ships
- Some fruits (like coconuts)
These objects float because their overall density (how compact the material is) is less than that of water.
- Objects That Sink: These objects are heavier or denser than water, which means they don’t displace enough water to float. Common examples include:
- Stones
- Metal objects (like coins)
- Some fruits (like apples when they are fully submerged)
These objects sink because they are heavier for their size or they don’t displace enough water to stay afloat.
2. Importance of Floatation on Water in Technology
Floatation on water is very important in many areas of technology, especially for transportation and safety. Here are some examples:
- Boats and Ships: Boats and ships use floatation to stay on the surface of the water. Their large size and shape help displace enough water to keep them from sinking. This is how large ships can carry goods and people across the oceans.
- Life Jackets: Life jackets are designed to help people float in water. They are made of materials that are less dense than water, so they keep people safe by keeping them afloat if they fall into the water.
- Oil Platforms: These are large structures used in the ocean to collect oil. They float on water because of their shape and the materials used to build them. Without floatation, they wouldn’t be able to stay on the surface.
- Floating Docks and Platforms: These are used in places like harbors to allow boats to park safely. They float because they displace enough water to stay above the surface
Lesson Presentation (Step-by-Step Procedure)
Step 1: Introduction
Start by asking: “What happens when you place a stone and a plastic cup in water? Do they behave the same way?” Encourage pupils to share their experiences with floating and sinking objects.
Step 2: Explanation
Explain floatation in water, emphasizing that it depends on the material and shape of the object. Mention that light objects or objects with a lot of air inside (like a plastic bottle) are more likely to float.
Step 3: Demonstration
Using a plastic spoon, iron spoon, and cork, show pupils what happens when each object is placed in water. Discuss why the plastic spoon and cork float, while the iron spoon sinks.
Step 4: Guided Practice
Allow pupils to experiment with various objects (e.g., bottle caps, small stones, paper) in a water container to see which float and which sink. Guide them in making observations.
Step 5: Independent Practice
Encourage pupils to draw or list objects from home that float or sink and explain why they think each object behaves that way.
Step 6: Feedback
Discuss their findings and correct any misconceptions. Reinforce the idea that floating and sinking depend on object materials and their interaction with water.
Evaluation
- Formative Assessment: During the activities, ask questions to check pupils’ understanding of why some objects float and others sink.
- Summative Assessment: At the end of the lesson, have pupils list two objects that float on water and two that sink. Ask them to explain the importance of floatation for boats and other technology.
Summary/Conclusion
Summarize by highlighting the difference between floating and sinking objects. Reinforce the importance of floatation in water transportation, as it allows boats, ships, and life-saving equipment to stay afloat.
Assignment
Ask pupils to find three objects at home that can float on water and three that sink. Have them write a sentence explaining why they think each object floats or sinks.