Air and water
Answer the following questions: 1. What is the percentage of oxygen in the atmosphere? Ans: The percentage of oxygen in the atmosphere is 21% . 2. Name the instrument which is used to measure atmosphere pressure. Ans: The instrument which is used to measure atmosphere pressure is Barometer . 3. Name two methods of purify water. Ans : Boiling and filtration are two methods of purify water . 4. What is loading Ans: Loading is process in which heavy particles settle down at the bottom . 5. Write an activity to show that air occupies space. Ans: • Take an empty glass and a bucket half filled with water. • Put the inverted glass into the bucket of water. This must be done very quickly and forcefully. The glass must be kept straight and put inside in an inverted position. • The water does not enter the inverted glass. Why? The air present in the empty glass prevents the water from entering it. • When we tilt the glass held in water, we find that of air present in the glass goes out in t