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๐ฌ Think about it
The word "pure" is on packs of milk, ghee, and spices. But "pure" means one thing to your mother and another thing to a scientist. Let's see why a scientist might call "pure milk" impure.
What does "pure" mean in common usage?
- In daily life, "pure" means unadulterated.
- Adulteration is adding cheaper or poor-quality substances illegally.
- It is done to increase quantity or cut cost.
- It lowers quality and can make a product unsafe.
Example:
Mixing cheap starch into "pure" turmeric powder is adulteration.
What does "pure" mean in science?
- A pure substance has no other substance in it.
- It is made of the same type of particles.
- It cannot be separated into other kinds of matter by physical means.
- So "pure" milk is impure to a scientist — it has many substances.
"Pure" in common usage
"Pure" in science
Means unadulterated.
Means only one type of particle.
Milk and ghee can be "pure".
Milk is impure — it has many substances.
Focus is on quality and safety.
Focus is on a single substance.
๐ก A step further
- According to science, classify these as mixtures or pure substances.
- Milk, packed fruit juice, and soil are mixtures.
- Baking soda and sugar are pure substances (compounds).
Important Points
- "Pure" in daily life means unadulterated; in science it means one substance.
- A pure substance has only one type of particle.
- It cannot be separated by any physical process.
Important Definitions
- Pure substance — matter made of the same type of particles that cannot be separated by physical means.
- Adulteration — the illegal adding of cheaper or poor-quality substances to a product.
๐ NCERT Question 4 — In which of the
In which option are all examples correctly matched as elements, mixtures, or pure substances?
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