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Chapter Review:

• All objects around us are made of one or more materials.
• These materials may be glass, metal, plastics, wood, cotton, paper, mud or soil.
• Materials that have lustre are usually metals.
• Salt and sugar are soluble materials.
• Iron fills and stones are insoluble materials.
• Different types of materials have different properties.

Exercise (NCERT Text Book)

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Q1:  Name five objects which can be made from wood.

Ans : chair, window, table, bed and doors

Q2:  Select those objects from the following which shine:

       Glass bowl, plastic toy, steel spoon, cotton shirt

Ans :  Glass bowl, steel spoon.

Q3:  Match the objects given below with the materials from which they could be made. Remember, an object could be made from more than one material and a given material could be used for making many objects.

Objects                               Materials

Book                     Glass

Tumbler                Wood

Chair                     Paper

Toy                        Leather

Shoes                    Plastics

Ans :

Objects                               Materials

Book                     Paper

Tumbler                Glass

Chair                     Wood

Toy                        Plastics

Shoes                    Leather

 

Q4:   State whether the statements given below are True or False.

1. Stone is transparent, while glass is opaque.
2. A notebook has lustre while eraser does not.
3. Chalk dissolves in water.
4. A piece of wood floats on water.
5. Sugar does not dissolve in water.
6. Oil mixes with water.
7. Sand settles down in water.
8. Vinegar dissolves in water.

Ans :

1. False
2. False
3. True
4. True
5. False
6. False
7. True
8. True

Q5:  Given below are the names of some objects and materials: Water, basket ball, orange, sugar, globe, apple and earthen pitcher Group them as:

(a) Round shaped and other shapes

(b) Eatables and non eatables

Ans :

(a) Rounded shaped : basket ball, Orange, globe, apple. 

      other shapes : Water, sugar, earthen pitcher.

(b) Eatables: Water, orange, apple, sugar.

     Non eatables: Basket ball, globe and earthen pitcher.

Q6:   List all items known to you that float on water. Check and see if they will float on an oil or kerosene.

Ans: The items which float on water are as Balloons, football, dry leaf, boats, steal glass, a piece of dry wood, oils.

          These all also float on an oil or kerosene.  

Q7:   Find the odd one out from the following:

1. Chair, Bed, Table, Baby, Cupboard
2. Rose, Jasmine, Boat, Marigold, Lotus
3. Aluminium, Iron, Copper, Silver, Sand
4. Sugar, Salt, Sand, Copper sulphate

Ans :

1. Baby
2. Boat
3. Sand
4. Sand

Important Questions with solution

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Q1: On what basis all materials are grouped?

Ans : Materials are grouped together on the basis of similarities and differences in their properties.

Q2: Why are all materials grouped together?

Ans : Things are grouped together for convenience and to study their properties.

Q3: Give three examples of metals.

Ans : Iron, aluminium and copper.

Q4: What are soft materials?

Ans : Materials which can be compressed or scratched easily are called soft materials. Like cotton and sponge.

Q5:  What are hard materials?

Ans : some other materials which are difficult to compress are called hard. Like iron and copper.

Q6: What are soluble materials?

Ans : some substances have completely disappeared or dissolved in water. These substances are called soluble materials. Example – salt and sugar.

Q7: What are insoluble substances?

Ans : Some substances do not mix with water and do not disappear even after we stir for a long time. These substances are called insoluble materials. Examples – iron fills, stone, rubbers etc.

Q8: Name five objects which float in water.

Ans : balloon, dry leaf, ball, dry wood, oils etc.

Q9: Name five objects which sink in water.

Ans:  key, stone, rod, brick and glass.

Q10: What are transparent objects?

Ans : Some materials through which things can be seen. These are called transparent materials. Glass, water, air and some plastics are examples of transparent materials.

Q11: What are opaque objects?

Ans :  some materials through which you are not able to see. These materials are called opaque. Wood, cardboard and paper are examples of opaque objects.

Q12: What are translucent objects?

Ans : The materials through which objects can be seen, but not clearly, are known as translucent. Like oily paper, polythene, oil and fiber sheet.  

Important Question with solution:

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Que1: what do you mean by classification?

Ans: Classification is the grouping or sorting together of thing possesing similar or dissimilar characteristics or properties.

Que2: what is the need for classification?

Ans: Classification is essential for:

• identification of objects.
• sorting of objects.
• locating things.
• understanding similarties and dissimailarities among objects.
• making the object easy and more meaningful.

Que3: why is mercury used in making thermometers?

Ans: 

• Mercury is liqid at room temperature.
• it is a good conductor of heat.
• Mercury has lustre so, it is easy to read the temperature shown by the level of mercury.

Que4: Why do we need the grouping of object?

Ans: Group the object helps us to arrange them in a systematic manner. The object when ground are easy to hanble. When grouded, it is easy to know the properties of an object clearly. Grouping also makes easy to compare two objects.

Que5: Why is what important for our body?

Ans: Water can dissolve a large number of substances, so it is needed by the body. it is also major part os our bosy cells.

Que6: List five eacgh opaque and transparent materials?

Ans: Opaque materials:

• Wood 
• Iron
• Cardboard
• Brick
• Gold

Transparent materials:

• Water
• Glass
• Air
• Cellophine plastic and
• fibre glass.

Que7: Why is water called unversal solvent?

Ans: The property of water to dissolve large number of materials makes it a universal solvent.

Que8: State conditions when pure water can lose transparency?

Ans: water on cooling, freezes to from ice which is not transparent.

Que9: Why is a tumbler not made with a piece of cloth?

Ans: The is beacuse we generally use a tumbler to keep a liquid. A tumbler made of a piece of cloth cannot be keep water. So, a tumbler is made with a material which has a property to hold the liquid.

Que10: Name two gases each which are soluble and insoluble in water. 

Ans: Gases soloble in water are Oxyen and carbon dioxide. Gases insoluble in water are hydrogen and nitrogen.