Chapter 6 Solutions — Materials Around Us

Let Us Enhance Our Learning

1. 1.
   Visit your kitchen and observe how your parents have organised various edibles. Can you suggest a better sorting method? Write it in your notebook.
2. 2.
   Unscramble the letters (Column I) and match with their properties (Column II). Column I:

   • (i) T R E M A T,
   • (ii) U L S B E L O,
   • (iii) T N E R P A S N A R T,
   • (iv) E R U S T L Column II:
   • (a) Objects can be seen clearly through it,
   • (b) Occupies space and has mass,
   • (c) Shiny surface,
   • (d) Mixes completely in water
3. 3.
   The containers which are used to store materials in shops and at home are usually transparent. Give your reasons for this.
4. 4.
   State whether the statements given below are True [T] or False [F]. Correct the False statement(s).

   • (i) Wood is translucent while glass is opaque.
   • (ii) Aluminium foil has lustre while an eraser does not.
   • (iii) Sugar dissolves in water whereas sawdust does not.
   • (iv) An apple is a matter because it occupies no space and has mass.
5. 5.
   We see chairs made up of various materials, such as wood, iron, plastic, bamboo, cement and stones. Following are some desirable properties of materials which can be used to make chairs. Which materials used to make chairs fulfil these properties the most?

   • (i) Hardness (does not bend or shake on sitting even after long use).
   • (ii) Lightweight (easy to lift or to take from one place to another)…
6. 6.
   You need to have containers for collection of:

   • (i) food waste,
   • (ii) broken glass and
   • (iii) wastepaper. Which materials will you choose for containers of these types of waste? What properties of materials do you need to think of?
7. 7.
   Air is all around us but does not hinder us from seeing each other. Whereas, if a wooden door comes in between, we cannot see each other. It is because air is ___ and the wooden door is ___. Choose the most appropriate option:

   • (i) transparent, opaque
   • (ii) translucent, transparent
   • (iii) opaque, translucent
   • (iv) transparent, translucent
8. 8.
   Imagine you have two mysterious materials, X and Y. When you try to press material X, it feels rigid and does not change its shape easily. On the other hand, material Y easily changes its shape when you press it. Now, when you mix both materials in water, only material X dissolves completely, while material Y remains unchanged. What can materials X and Y be? Can you identify whether material X…
9. 9.
   Who am I? Identify me on the basis of the given properties.

   • (a) I have lustre.
   • (b) I can be easily compressed.
   • (c) I am hard and soluble in water.
   • (d) You cannot see clearly through me.
   • (e) I have mass and volume but you cannot see me.
   • (ii) Make your own 'Who am I?'
10. 10.
    You are provided with the following materials — vinegar, honey, mustard oil, water, glucose and wheat flour. Make any two pairs of materials where one material is soluble in the other. Now, make two pairs of materials where one material remains insoluble in the other material.