Changes Around Us

True

No

This is a change which cannot be reversed

No

The shape and size of balloon can be changed by blowing it.

No

False

Reversible

Yes

This is a change which cannot be reversed

True

Irreversible change

Reversible change

Yes

Irreversible

Yes

They can again get wet if we put them in water.

Yes

False

No

True

Contracts.

Liquid water

Expands

Water vapour

Yes.

No

Reversible

Not be reversed

This is a reversible change.

It turns into ash. It is not a reversible change.

Yes.

True

No

False

True

We can defrost the mango pulp.

Everyone desires and appreciates baby growth.

It is a reversible change. It increases or decreases with Engine temperature

Reversible process is a process that, after it has taken place, can be reversed and, when reversed, causes no change in either the system or its surroundings.

Ice melts when it is heated and converts to water. Water again changes into ice on freezing.

A chemical change is a process where one or more substances are altered into one or more new and different substances.

On folding paper in ball shapes its physical appearances changes.

Electric wire goes through irreversible changes and breaks.

The change due to shortening of the candle after burning cannot be reverse. So, it irreversible change.

Freezing is reversible. For example ice melt n turns into water on heating. Again water freezes and forms ice.

Ans: a.

Thermal expansion is tendency of matter to change in shape, area, and volume in response to a change in temperature.

Ans: b.

Reversible process is a process that, after it has taken place, can be reversed and, when reversed, causes no change in either the system or its surroundings.

Reversible process is a process that, after it has taken place, can be reversed and, when reversed, causes no change in either the system or its surroundings.

It changes size of nail.

Metals expands on heating and contracts on cooling.

Since all reversible changes after being in different form temporarily retakes its original firm. So it is also called temporary change.

The pendulum of a clock made of ordinary metal expands and contracts due to variations in the temperature. In summer, the length of the pendulum increases, and in winter, it decreases. As a result of it, an error creeps into the time shown by the clock. To show the correct time, the pendulum is made of invar-steel, which has negligible expansion and contraction due to variations in temperature.

Non-Periodic changes are changes which do not repeat itself after fixed interval of time.

Periodic changes are changes which repeat itself after fixed interval of time.

For example in a burning candle, there are both physical and chemical changes. The burning of the wax vapour is a chemical change. The wax vapour reacts with oxygen in the air to form new substances including carbon dioxide and ash.

Falling of leaves is permanent. Once leaves falls, it cannot be put again on tree.

Once cement gets wet, it gets fix at its place. It can't be changed.

Germination is the process of seeds developing into new plants. It took seeds time to get germinated. It's a slow process.

Telephonic cables contracts in winter. These are left little loose to avoid breaking.

Non-Periodic changes are changes which do not repeat itself after fixed interval of time.

Mercury works by having a constriction in the neck close to the bulb. As the temperature rises, the mercury is pushed up through the constriction by the force of expansion.

Gaps are provided to allow room for the rails to expand the rise in temperature due to the atmospheric temperature as well as the friction caused by running of train. All materials expand when heated and contract when cooled.

When a match stick is lighted it immediately burns, its length decreases changing its composition.