Std 6 General Science · Chapter 3

3. Let’s Separate the Components

Complete solutions to the Exercises, including the word search solved. Maharashtra State Board (Balbharati), Grade Six General Science.

About the chapter

Many things around us are mixtures. This chapter tells us how to separate the components of a mixture. The method depends on the properties of the components. We learn simple methods used at home, on farms and in industries.

Key points

Handpicking, winnowing and sieving are used to clean grains.
Filtration separates undissolved solids from a liquid.
Sedimentation and decantation separate heavy insoluble particles from a liquid.
Evaporation separates a dissolved solid, like salt, from water.
Churning separates butter from curd.
Magnetic separation removes iron objects with the help of a magnet.

Words to remember

mixture – two or more substances mixed together
component – each substance present in a mixture
sediment – heavy particles that settle at the bottom
decantation – pouring out the clear liquid without disturbing the sediment
evaporation – changing of a liquid into vapour by heating

Exercises

1Choose the correct option.

(1) In magnetic separation, …… is used.

(a) difference in density
(b) difference in size
(c) magnetic property — correct
(d) solubility property

(2) To separate small stones from wheat, the …… method is useful.

(a) threshing
(b) handpicking
(c) winnowing
(d) sieving — correct

(3) Alum dissolved in water can be separated using the …… method.

(a) evaporation — correct
(b) sedimentation
(c) filtration
(d) decantation

(4) There is a doubt that water is mixed with milk. Separating the milk and water will be possible through …… method.

(a) filtration
(b) evaporation
(c) sedimentation and decantation
(d) not possible by any of these methods — correct

2State whether true or false. If false, state why.

(1) The filtration method is used to separate substances that are not dissolved in a liquid.

True.

(2) Using magnetic properties, all metals can be separated from garbage.

False. Only iron, cobalt and nickel are attracted by a magnet.

(3) The sedimentation method is used to separate salt from seawater.

False. Salt is dissolved in seawater. So it is separated by evaporation.

(4) The winnowing method is used to separate lightweight debris from grains.

True.

(5) The decantation method can be used to separate two liquids, one heavy and one light.

True.

3For which type of mixture is the filtration method useful and how?

Filtration is useful for a mixture of a liquid and an undissolved solid, e.g. muddy water, tea with tea leaves.

Pour the mixture through a filter paper or cloth.
The liquid passes through the tiny holes.
The solid particles stay on the filter.

4How will you separate sawdust mixed in a container of water?

Sawdust does not dissolve in water. It floats.
Pour the mixture through a cloth or filter paper.
Water passes through. Sawdust stays on the cloth.
This method is called filtration.

5While working, a carpenter finds that iron nails have mixed with sawdust. Which different methods can the carpenter use to separate them? Which of those methods is the easiest?

Magnetic separation – a magnet picks up the iron nails.
Sieving – fine sawdust falls through the sieve. The nails stay on it.
Winnowing – light sawdust is blown away by air.
Handpicking – nails are picked out by hand.

The easiest method is magnetic separation. It is quick. It picks up all the nails at once.

6In the word search below, some words related to separation are given. One example has been circled for you. Find all such words in the word search and write them down.

All eight words found. Row 8 reads backwards, from right to left.

The words are:

Sedimentation
Winnowing
Decantation
Sieving
Magnetic separation
Evaporation
Filtration
Churning

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