Evaporation and Condensation

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

Learn

How do we get salt from seawater? Along the coasts of Gujarat and Tamil Nadu, seawater is let into shallow beds. The sun and wind evaporate the water, and salt is left behind as crystals.

You can try it: dissolve a spoon of salt in water, pour it into a plate and keep it in the sun for a few days. The water disappears and salt crystals remain. Evaporation separates a dissolved solid from a liquid.

And to get the water back too? Boil salty water in a covered pan. Vapour rises, condenses on the cool lid, and pure water drips off it into a cup, leaving the salt in the pan: evaporation followed by condensation.

Explore: pick the right method.

1. Sort each one.

Remember

• Evaporation separates a dissolved solid (like salt) from a liquid.
• Evaporation followed by condensation gives back pure water.

Quick check

Which method gets salt from salt water?

1. Evaporation
2. Filtration
3. Sieving
4. Winnowing

Think about it

Plan how to get both sand and salt back from a mixture of sand, salt and water.

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.