Innovative Activity-Based Teaching – Archimedes’ Principle
Date: August 25, 2025
Essence:
- Discover how objects seem lighter in water.
- Understand buoyant force and its connection to displaced fluid.
- Grasp the core idea of Archimedes’ principle intuitively.
Explore:
- Materials: beaker or tub of water, small objects (metal spoon, pebble, plastic toy), spring scale (if available).
- First, weigh each object in air, here on a measuring scale or by feel.
- Then, submerge them one by one in water—observe how they feel lighter or float.
- Note differences and encourage predictions (Does a heavy rock still sink? Does a hollow shell float?).
Explain:
The apparent loss in weight when submerged is called the buoyant force. According to Archimedes’ Principle: “An object immersed in a fluid experiences an upward force equal to the weight of the fluid displaced by it.”
Elaborate:
- Use clay to make a sphere—observe it sinks. Then reshape it into a boat shape—the same clay may float. Discuss why!
- Compare sinking behavior between solid metal piece vs. thin-walled metal boat (same weight but different volume displaced).
Evaluate:
Use the rainbow mind map below to reinforce what you've learned:
- Archimedes’ Principle: Buoyant force equals weight of displaced liquid.
- An object feels lighter when submerged.
- Buoyant force acts upward, opposite to gravity.
- Objects float if buoyant force ≥ weight.
- Sinking if object is denser than fluid.
- Shape changes (boat vs sphere) affect float/sink.
- Helps in designing ships, submarines, etc.
