Differentiate among opaque, translucent and transparent materials, by giving one example of each.

Chalk, iron nail, wood, aluminium, candle, cotton usually look different from each other. Give some properties by which we can prove that these materials are different.

(a) What do you understand by the term 'classification'?
(b) Differentiate between transparent and opaque materials. Give two examples for each.
(c) How can we make a normal paper translucent?

During summer holidays, a group of children collected a lump of salt, green grass, broken glass piece, a small thermocol box, pen, iron nail, glass. marbles, hair, naphthalene ball, a piece of sugar candy (mishri) and tried to group them on the basis of properties given in table. Help them in filling the table.

Rohan and his friends planned to play cricket match on sunday morning. But, by chance on saturday, Rohan got high fever. Due to high fever, his parents did not allow him to play cricket. So, Rohan was very upset. But his father suggested to him that he can see the cricket match that his friends were playing in the park through a glass window, although the window will be closed
Read the above passage and answer the following questions.
(a) How Rohan was abie to see the cricket match, although the window was closed?
(b) Write different types of materials based on their transparency.
(c) What values are shown by Rohan's father?.

Chalk, iron nail, wood, aluminium, candle, cotton usually look different from each other. Give some properties. by which we can prove that these materials are different.

Why do you think oxygen dissolved in water is important for the survival of aquatic animals and plants.

Kavita bought new silver anklets. After a month, she found that the anklets had lost their lustre and turned black. She had doubts that they were not made of pure silver. But her mother told her that they were of pure silver. She washed her silver anklets with lemon juice and found that the silver anklets had get the lustre back.
Read the above passage and answer the following questions.
(a) Do you think that the anklets are not of pure silver?
(b) Why silver anklets lost their lustre after some time?
(c) What values were shown by Kavita's mother?

Sugar, salt, mustard oil, sand, sawdust, honey, chalk powder, petals of flower, soil, copper sulphate crystals, glucose, wheat flour are some substances given to Paheli. She wants to know whether these substances are soluble in water or not. Help her in identifying soluble and insoluble substances in water.