Slow and Fast Changes

Q. The changes that take place in a short duration of time are called ___ .

Q.

8. Bursting of crackers is reversible change.

1. True
2. False

Q.

What is riveting? Explain.

Q.

Question 17

Conversion of ice into water and water into ice is an example of change which can be reversed. Give four more examples where you can say that the changes can be reversed.

Q. Increase in height of humans is an example of a ______ change.

1. reversible
2. slow
3. fast
4. chemical

Q. The appearance of the full moon is an example of a periodic change.

1. False
2. True

Q. Which of the following change is classified based on the speed?

1. Slow
2. Natural
3. Temporary
4. Man-made

Q.

10. Write the changes that can be notice in our body easily.

Q. Which of the following are examples of reversible change?

1. Moulding clay to form a toy
2. Ripening of fruits
3. Cutting a piece of paper
4. Putting pencil mark on a paper

Q.

“How is the principle of regelation applicable for welding?” Explain.

Q. Which of the following processes is to be followed to bend an iron rod into a circular loop?​

1. Heating the rod
2. Cooling the rod
3. Dropping the rod
4. Stretching the rod

Q. Bursting of fire crackers is a_______ change whereas germination of seeds is a_______ change.

Q.

Question 15

Give one example in each case.
Change which occurs on heating but can be reversed.
Change which occurs on heating but cannot be reversed.
Change which occurs on cooling but can be reversed.
Change which occurs on mixing two substances but can be reversed.
Change which occurs on mixing two substances but cannot be reversed.

Q. In the process of ______, a solid substance absorbs heat from the surroundings.

1. condensation
2. evaporation
3. melting
4. freezing

Q.

Which of the following is a fast change?

1. Rusting of iron

2. Germination of seed

3. Weathering of rock

4. Glowing of an electric bulb

Q. Which of the following is a reversible change?

1. Burning wood
2. Cutting paper
3. Cooking chapatis
4. Folding paper

Q. What is a reversible change? Can all the changes be reversed?

Q. What is common among the following changes:
1. Blinking of traffic lights
2. Rotation of fan blades

1. Irreversible
2. Undesirable
3. Periodic
4. Natural

Q.

1. Few children were inflating balloons.
2. Farmers were harvesting crops in their fields.

Among the above-mentioned observations, which are the examples of reversible change?

1. Both observation 1 & observation 2 are irreversible changes.

2. Only observation 1 is a reversible change.

3. Only observation 2 is a reversible change.

4. Both observation 1 & observation 2 are reversible changes.

Q. 1. Few children were inflating balloons.
2. Farmers were harvesting crops in their fields.

Among the aforementioned observations, which one is the example of reversible change?

1. Only observation 1 is a reversible change.
2. Only observation 2 is a reversible change.
3. Both observation 1 & observation 2 are reversible changes.
4. Both observation 1 & observation 2 are not reversible changes.

Q. The given figure shows the rotation and revolution of the earth on its axis and around the sun respectively.

What kind of change does the earth undergo?

1. Undesirable change
2. Physical change
3. Chemical change
4. Periodic change

Q. Which of the following is not a reversible change?

1. Crumpling paper
2. Melting ice-cream
3. Cooking noodles
4. Boiling water