Air pressure Concepts - Flashcards
Air pressure concepts-
As the pressure of an area reduces, wind speed
increases and vice versa. Higher the pressure
difference, higher the speed of wind.
Thus, the two major concepts are:
High speed winds are accompanied by reduced
air pressure.
Air travels from high pressure areas to low
pressure areas.
Example-
Blowing air between two balloons tied to a rod. DOUBT IN THIS WILL ASK SIR
1 more example -
Since the pressure inside the bottle becomes higher than that outside the bottle when air is blown, the paper ball doesn’t go inside. In fact, ball comes out of the bottle (from higher pressure to lower pressure area)
2nd example
Birthday poppers paper strip
Air expands on heating-
Air molecules expand on heating and contract on
cooling.
Hot air molecules take more space than cold air
molecules.
Warm or Hot air is lighter than cool air.
Warm air, like smoke, rises up and cool air
settles down.
When warm air rises up, it creates low pressure
in the area, so surrounding cooler air, from
relatively higher pressure, then comes to take up
its place.
Examples -
When a test tube is immersed in hot water, the
air inside it expands and tries to take more
space. On the other hand, when immersed in
cold water, the air inside the tube contracts a
little and tries to take up lesser space than
normal.
Practical example -
A balloon gets a little blown up when attached to a tube under hot water.
A balloon gets sucked inside when attached to a tube under cold water.
Practical example -
Hot air from candle goes inside in one of the paper bag. The other bag has normal air.
Hot air, being lighter from normal air, moves up and takes the paper bag up with it. the other bag has cooler air, hence it goes down.
IMPORTANT
In the afternoon, the wind blows from sea to land.
As pressure on the land is less than the pressure
above sea,
Q. Rohan was very happy that there was his birthday.
He was decorating the room by blowing balloons. He
was wondered that most of his balloons bursted. He
rushed to his father and asked the reason. His father
smiled and explained.
(a) Can you explain the reason that why his balloons
get burst?
(b) What can be conclude from the condition
mentioned?
A. (a) When Rohan blows air into the balloon, the
balloon gets inflated due to the pressure exerted
by air. But, Rohan observed that most of his
balloons bursted. The reason behind it was, he
overfilled the air into the balloon. The warm air
gets expanded inside the balloon and exerted
more and due to the more pressure on the walls
of the balloon, balloons bursted.
(b) From the condition mentioned above, it can be
concluded that air expands on heating.
