Churning and Magnetic Separation

Class 6 Science · Chapter 9: Methods of Separation in Everyday Life · NCERT Curiosity section Ch 9

Learn

In many Indian homes, curd is churned with a wooden mathani (churner) to make butter. Churning makes the tiny bits of butter come together and float on top, leaving buttermilk (chhaachh) below.

What if iron pins fall into a box of sand or flour? Move a magnet through it: the iron pins stick to the magnet and the rest stays behind. Scrap yards use giant magnets to pick out iron from other waste.

Often we need more than one method: to clean a mixture of sand, iron filings and salt, first use a magnet (iron), then dissolve and filter (sand), then evaporate (salt). Choosing methods depends on the properties of each part: size, weight, magnetism, and whether it dissolves.

Explore: choose a method for each mixture.

1. Sort each mixture to its best method.

Remember

• Churning separates butter from curd; a magnet separates iron from a mixture.
• Choose methods by the properties of the parts; often more than one is needed.

Quick check

How would you separate iron filings from sawdust?

1. With a magnet
2. By winnowing
3. By evaporation
4. By churning

Think about it

Gandhiji led the Salt March to Dandi in 1930 and made salt from seawater. Which separation method did people use to make that salt?

Practice

Practise with fresh questions at three levels (easy, medium, hard), some answered hands-on, with hints and worked answers. Get 4 of your last 5 right to finish the topic.