Important Questions with solution
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.