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๐ฌ Think about it
Drop a coin and it sinks; drop a wooden spoon and it floats. While washing rice, the light husk floats and the rice sinks. What decides this? A property called density. Let's begin to understand it.
Why do some objects float while others sink?
- Generally, objects lighter than the liquid float.
- Objects heavier than the liquid sink.
- Iron feels heavier than wood of the same size.
- This heaviness is a property called density.
Example:
While washing rice, the light husk floats while the heavier rice sinks.
๐ก Note
- Density is not the only factor for floating or sinking.
- Other factors also affect whether an object floats in a liquid.
Important Points
- Lighter-than-liquid objects float; heavier ones sink.
- Density describes the heaviness of an object.
- Density alone does not fully decide floating or sinking.
Important Definitions
- Density (idea) — a property that describes the heaviness of an object of a given size.
โ Test Yourself
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Why does husk float while rice sinks?
View Answer
Husk is lighter than water for its size, so it floats; rice is heavier than water, so it sinks. -
What property describes the heaviness of an object?
View Answer
Density — it compares how heavy an object is for its size. -
Does oil float or sink on water?
View Answer
Oil floats, because it is less dense than water. -
Is density the only factor for floating or sinking?
View Answer
No. Density is important, but it is not the only factor that decides floating or sinking in a liquid. -
Between same-size wood and iron, which is denser?
View Answer
Iron, because it feels much heavier than wood of the same size.
๐ NCERT Question 3 — You pour oil into
Oil floats on water in a glass. What does this tell you about their densities?
View Answer →
