Question

Q-1 : Why are ventilators situated high up near the ceiling of a room ?

Q-2 : Why does smoke rise ?

Q-3 : What happens when we touch a cold metal spoon ? Why does it feel cold ? Explain

Answer 1

1)In the room when air is hot its decrease and rise up.So ventilators help to remove out air from the room and make temperature same.So ventilators are made close to celling

2) A fire makes things hot. Above a fire, you get quite a lot of hot air. Hot air is less dense than cool air, so it rises. Because there is quite a lot of hot air, it makes quite a big wind current as it rises, and that drags the smoke particles upward with the air, in much the same way as wind can raise dust. Some of the smoke particles are very small indeed, so they can be held up in the air for quite a long time, and they do not settle out from the air until a long time after they leave the fire, and usually some distance away from the fire
3)When we touch an object that is lower temperature than your fingers,the object feels cold because heat goes through your fingers into the object,not because coldness enter your body.The flow of energy always from hotter to colder one.