Common examples are (2)___________ and (3)_________.

Fire will continue its flame provided that there is continuous supply of

(4)_______, (5)_______, and (6)________.

In the absence of oxygen, there will be no (7)______ that will occur.

An example of change in the material when oxygen is present is ________.

______ is formed when iron and oxygen react with water or air moisture.

1.What change will happen to the slices of potato if they will be exposed to oxygen in the air?

2. What causes the rusting of iron nails or iron made materials in a wet cloth?

3. When the candle was lighted, it melted into liquid and became solid again after few seconds or in a minute. What causes these changes?

I. presence of heat II. presence of oxygen

III. absence of heat IV. absence of oxygen

4.Why a slice of an apple acquires a brown colour if it is not consumed immediately?

5. Which situation shows the presence of oxygen in a material?

I. Lighting of a candle III. Combustion of engines

II. burning of fuels IV. putting off a lighted candle

6. Water is the primary cause of rust because water contains _____?

7. What process is being shown in the picture?

8. Joram noticed that when he mopped the floor using wet rugs, the moist in the floor disappeared after few minutes. What is the reason why the floor became dry?

9. When physical change in materials happened, there is__________.

I. formation of new product or material

II. no formation of new product or material

III. formation of new shape

IV. formation of new color

10. Hannah observed that the left over foods on the table became watery, spoiled and had foul odor after 48 hours. What caused this change in the material?

I. presence of heat III. presence of oxygen

II. absence of heat IV. absence of oxygen