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An iron ring is heated. Which of the following statement about it is incorrect? (a) The ring expands. (b) The ring almost comes to the same size on cooling. (c) The change, in this case, is reversed. (d) The ring changes its shape and the change cannot be reversed.

Answer: (d) The ring changes its shape and the change cannot be reversed. The change is reversible in case of an iron ring. Since the ring... View Article

Which of the following change cannot be reversed? (a) Hardening of cement (b) Freezing of ice cream (c) Opening a door (d) Melting of chocolate

Answer: (a) Hardening of cement Hardening of cement is cannot be reversed because once hardened it cannot come back to its original shape. Change... View Article

Pick the change that can be reversed from the following. (a) Cutting of trees (b) Melting of ghee (c) Burning of candle (d) Blooming of flower

Answer: (b) Melting of ghee The melted ghee can be frozen again hence this change can be reversed. Change in chemistry can be explained on the... View Article

Sugar, salt, mustard oil, sand, sawdust, honey, chalk powder, petals of a 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.

Answer: The solubility is the maximum amount of solute that can dissolve in a known quantity of solvent at a certain temperature. The... View Article

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

Answer: Opaque materials Translucent materials Transparent materials Those substances through which objects cannot be seen are termed... View Article

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

Answer: Materials that can be compressed are known as soft materials. Materials that cannot be compressed are known as hard materials. Lustrous... View Article

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.

Answer: Few properties by which we can prove that these materials are different: Chalk – Hard, rough, non-lustrous Iron nail –... View Article

Arrange the jumbled words to arrive at the appropriate names of materials and also write two uses of each. (a) milaunuim (b) tcaslpi (c) soekrnee (d) gavnier

Answer: The arranged word are: (a) Aluminium – It can be used to wrap food in the foil, in making aircraft, etc. (b) Plastic – It... View Article

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 below. Help them in filling the table.

Answer: Transparent substances are those substances or materials that allow things to be seen through them. Almost all light beams are able to... View Article

You are provided with the following materials – turmeric, honey, mustard oil, water, glucose, rice flour, groundnut oil. Make any three pairs of substances where one substance is soluble in the other and any three pairs of substances where one substance remains insoluble in the other substances.

Answer: In our daily lives, we come into contact with a variety of substances. We experiment with them and come to a few conclusions before... View Article

Which among the following materials would you identify as soft materials and why? Ice, rubber band, leaf, eraser, pencil, pearl, a piece of a wooden board, cooked rice, pulses and fresh chapati.

Answer: Leaf, rubber band, cooked rice, eraser and fresh chapati are soft materials because they can be scratched or compressed easily.... View Article

Take a small cotton ball and place it in a tumbler/ bowl filled with water. Observe it for at least 10 minutes. Will it float or sink in water and why?

Answer: When a cotton ball is placed in water, it floats at first, but as the water is absorbed by the cotton by capillary action and the air... View Article

On a bright sunny day, Shikha was playing hide and seek with her brother. She hid herself behind a glass door. Do you think her brother will be able to locate her? If yes, why? If no, why not?

Answer: Yes, Shikha's brother will be able to track her down because glass is a transparent material. Transparent substances are those... View Article

Mixtures of red chilli powder in water, butter in water, petrol in water, and honey in water were given to Radha, Sudha, Sofia and Raveena, respectively. Whose mixture is in solution form?

Answer: Raveena will get the mixture in solution form. Since honey and water are soluble with each other hence a solution will be formed when... View Article

lt was Paheli’s birthday. Her grandmother gave her two gifts made of metals, one old dull silver spoon and a pair of lustrous gold earrings. She was surprised to see the difference in the appearance of the two metals. Can you explain the reason for this difference?

Answer: Because it was old and had been exposed to air for a long time, the silver spoon appeared dull. When silver is exposed to air, it reacts... View Article

Which type of the following materials is used for making the front glass (windscreen) of a car? (a) Transparent (b) Translucent (c) Opaque (d) All the above

Answer: (a) Transparent Transparent glass is used for making the front glass of a car so that everything can be seen clearly. Transparent... View Article

Find the odd one out from the following. (a) Tawa (b) Spade (c) Pressure cooker (d) Eraser

Answer: (d) Eraser Eraser is made up of rubber while Tawa, Pressure cooker and spade are made up of metal. Metals are minerals or substances... View Article

Which of the following statements is not true? (a) Materials are grouped for convenience. (b) Materials are grouped to study their properties. (c) Materials are grouped for fun. (d) Materials are grouped according to their uses.

Answer: (c) Materials are grouped for fun. Materials aren't grouped for the sake of fun. There's a reason they're grouped together. Materials are... View Article

Which of the following materials is not lustrous?(a) Gold (b) Silver (c) Wood (d) Diamond

Answer: (c) Wood Lustrous is defined as metals that have a shiny appearance. The shiny appearance of the metals is called metallic lustre. Wood... View Article

Which among the following are commonly used for making a safety pin? (a) Wood and glass (b) Plastic and glass (c) Leather and plastic (d) Steel and plastic

Answer: (d) Steel and plastic Steel can be moulded to get sharp points and plastic is used to seal the edges. Hence steel and plastic are used... View Article

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