Sorting Materials Into Group

Q41. Why do we need to classify things around us?

Ans. We need to classify things around us for the following reasons:

      i.     Organize them better help us to locate them easily.

      ii.    To study their properties.

      iii.  To decide which material to choose for a specific purpose.

Q42. Differentiate between transparent, translucent and opaque.

Ans.

Q43. Write properties of materials.

Ans. Properties of materials are:

a. Appearance

b. Hardness

c. Solubility

d. Density

e. Transparency

Q44. Why don’t we use paper or cloth for making tumbler?

Ans. We cannot use paper or cloth for making tumbler because

                          i.        Paper or cloth is not hard enough to hold water.

                        ii.        Cloth has tiny pores through which liquid will oozes out.

Q45. Write the similarities between gold, silver and copper.

Ans. Similarities between gold, silver and copper are:

                         i.        They all are metals.

                       ii.        They all have lustre.

                      iii.        They are hard.

Q46. Name some materials made up of paper.

Ans. books, notebooks, newspapers, calendars etc.

Q47. Write the materials the following objects made of.

Ans.    

Q48. Write the things made of following materials.

Ans.

Q49. How grouping of items help the shopkeeper?

Ans. Proper grouping of items helps the shopkeeper in the following ways:

                         i.        He can locate the items easily and in lesser time.

                        ii.        He can easily find out which item is about to finish and he can order them on time for his customers.

Q50. With help of an experiment prove that water is transparent.

Ans. Take a glass tumbler half filled with water. Drop a coin in the glass. Place the glass undisturbed for some time in a place where there is enough light. Now see the coin from the top of the glass. You can see the coin immersed in water clearly. This shows that water is a transparent liquid.

Q51. Write an experiment to show that sugar and salt is soluble in water whereas solid like sand and chalk are insoluble in water.

Ans. Take 4 beakers half filled with water. Add 1 teaspoonful of sugar to the first beaker, salt to second, sand to the third beaker and chalk powder to the fourth beaker. Stir content of each beaker. We will see that sugar and salt dissolve completely whereas sand and chalk powder do not dissolve.