Table of Contents
Introduction.
Hello students! I hope you’re all excited and ready for another interesting chapter in Science. Today, we’re going to explore something we all do at home, in the kitchen, at school, and even when we play. Yes – we’re talking about separating things. You might not realise it, but separation of substances is a part of our daily life.
Let’s join Arjun and Arya, who are going on a fun holiday across India. As they travel, they discover many amazing methods of separating mixtures – and we’ll learn with them!
Handpicking.
Now, let’s begin with something simple. Have you seen someone removing small stones from rice or wheat? That’s called handpicking.
Handpicking is useful when:
- The unwanted particles are large enough to pick out.
- The quantities are small.
- The difference in size or color is noticeable.
Just like Arjun removed black pepper from his pulao – that too was handpicking!
Threshing.
Now, Arjun and Arya go to the fields. Farmers are beating dry stalks of wheat. Why? To remove the grains!
This method is called threshing – separating grains from stalks. It’s mostly used in farming after harvesting. Nowadays, machines called threshers help do this faster.
Winnowing.
Next, Arjun and Arya see a farmer standing on a platform with a bamboo tray, tossing the grains into the air. The wind carries the husk away, while heavier grains fall straight down.
This is winnowing – used to separate lighter and heavier substances with the help of air or wind.
You’ll see how simple this is!
Sieving.
When Arya helps her Mami make meethi puri, she sees flour being sieved to remove bran and small stones.
Sieving is used when:
- You have a solid-solid mixture.
- The substances are of different sizes.
It’s just like how sand is sieved at construction sites to remove pebbles.
Evaporation.
In Ahmedabad, Arjun and Arya learn how salt is made from seawater. When the water is left out in the sun, it evaporates, leaving the salt behind.
Evaporation is the process where water turns into vapor, and the solid (like salt) is left behind.
Let’s try to understand this step by step:
- Mix salt and water.
- Leave it in sunlight or heat it gently.
- Water evaporates. Salt remains.
Think about this in your everyday life – have you seen white patches on dark clothes in summer? That’s salt from sweat!
Sedimentation and Decantation.
At Dadi’s house, Dada makes tea. But how does he separate tea leaves?
He lets the leaves settle down – that’s sedimentation.
Then, he pours the tea carefully into cups, leaving the leaves behind – that’s decantation.
This is useful when:
- One substance is insoluble and heavier.
- It settles at the bottom of the container.
This is also used when washing rice or pulses at home.
Filtration.
But sometimes decantation doesn’t remove everything. So, Dada uses a strainer. That’s filtration.
Filtration uses a barrier (like cloth or filter paper) to separate solids from liquids.
- Muddy water through cloth.
- Tea leaves through strainer.
- Filter paper for fine particles.
Arya even designs her own water filter using low-cost materials. You can try that too!
Churning.
Now, the family reaches Madhya Pradesh. At a dhaba, Arjun sees a painting of a woman using a mathni (churner) to make butter from curd.
This is churning – a method to separate butter (which is lighter) from buttermilk.
So next time you eat butter, remember – it’s the result of churning!
Magnetic Separation.
Finally, in Shillong, a carpenter drops iron nails in sawdust. Arjun uses a magnet and attracts all the nails out.
That’s magnetic separation – using magnets to pull out magnetic materials like iron from a mixture.
This is also used in recycling industries to remove scrap iron.
Summary.
Let’s quickly recall what we’ve learned:
- Handpicking – picking out unwanted substances by hand.
- Threshing – separating grains from stalks.
- Winnowing – separating heavier and lighter components using air.
- Sieving – separating particles of different sizes.
- Evaporation – removing water by heating.
- Sedimentation – letting heavy particles settle.
- Decantation – pouring off the clear liquid.
- Filtration – removing solids from liquids using a filter.
- Churning – separating butter from curd.
- Magnetic separation – using a magnet to remove magnetic materials.
Quick Review Questions.
- Which method would you use to remove pebbles from rice?
- What do you call the method used to separate tea leaves from tea?
Think about these and try to answer in your own words.
That’s all for today. Great job learning with Arjun and Arya! Keep observing your surroundings – science is everywhere. See you in the next chapter!
