Match Column I with Column II. There can be more than one match.

Describe an activity to demonstrate that warm air is lighter than cool air.

Paheli kept an empty bottle made of plastic inside a refrigerator. After a few hours, when she opened the refrigerator she found the bottle had collapsed. Explain the possible reason.

Match Column I with Column II. There can be more than one match.

To expel hot air out of the kitchen, ‘A’ has an exhaust fan fitted on the window of her kitchen and ‘B’ has a similar exhaust fan fitted on the wall near the ceiling of her kitchen. Which of the exhaust fan will expel the hot air more effectively? Explain why?

State whether the following statements are True or False:

(i) If wind flows from land to the ocean, then it is daytime.

(ii) A very high-pressure system, with very high-speed wind surrounding it, forms a cyclone.

(iii) The coast line of India is not vulnerable to cyclones.

(iv) Warm air is lighter than cool air.

Four schematic diagrams are shown in Figure 8.1 to depict the direction of sea breeze. Which of them gives the correct direction?

A fire alarm usually detects smoke in case of fire. Where should such an alarm be placed in a room?

Fill the missing word in the blank spaces in the following statements:

(a) Wind is _______ air.

(b) Winds are generated due to ________ heating on the earth.

(c) Near the earth's surface ________ air rises up whereas _________ air comes down.

(d) Air moves from the region of __________ pressure to a region of __________ pressure.

You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answers.