Changes around us

Which of the following changes cannot be reversed?

• Milk to paneer

• Cold milk to hot milk

• Yam to knitted sweater

• Wet clothes to dry clothes

Which one of the steps while burning a candle is not reversible?

• Melting of solid wax

• liquid wax changes into vapours

• Wax vapour bums into flame

• All of these

Which is a way to make a change happen?

• Heating a substance

• Cooling a substance

• Mixing a substance with another substance

• All of these

Rusting of iron is an example of

• Slow change

• Fast change

• Reversible change

• Physical change

Conversion of a solid to liquid by heating is called

• Evaporation

• Melting

• Condensation

• Freezing

Which of the following is not a man-made change?

• Change of day and night

• Burning of fuels

• Drying of clothes

• Tearing of paper

Which of the following is a chemical change?(a) Evaporation of water(b) Burning of fuels(c) Moving of a wheel(d) Breaking of a brick

• Evaporation of water

• Burning of fuels

• Moving of a wheel

• Breaking of a brick.

What are the changes that can be reversed called?

• Reversible changes

• Irreversible changes

• Contraction

• Evaporation

The effects of the changes are

• Change in size

• Change in shape

• Change in colour or taste

• All of these

Which of the following is a periodic change?

• Earthquake

• Flood

• Pendulum ringing after an hour

• volcano