Air Pressure explained - Winds, Storms & Cyclones Video Lecture - Class 7 | Best Video for Class 7

it's like this air pressure is always
pushing on us from all sides about 15
pounds of pressure for every square inch
but at the same time our bodies push
back against the air pressure with equal
force so it balances out and we don't
get crushed I wish I could see all this
well think of it this way picture air
molecules near the ground is being
packed tightly together by the weight of
the air above this is why air is much
denser at sea level but higher up in the
atmosphere there's a lot less air
pushing down from above so the air
molecules are not packed together so
tightly normally we don't feel any of
this unless the pressure changes sudden
you mean like when your ears pop in an
airplane exactly
at much greater heights there is less
air weight pressing on you your body is
reacting to the pressure change
scientists used barometers and other
tools to study the air pressure to
predict the weather and to study
climates you can measure changes in air
pressure too first we can do an easy
experiment to see how air expands as it
gets warmer take a balloon blow it up
slightly and attach to the top of an
empty soda or water bottle the larger
the better put the bottle in a freezer
meanwhile get a sink or tub a very warm
water ready after 10 minutes take the
bottle out of the freezer observe the
size of the balloon quickly submerse
most of the bottle under the very warm
water holds it in the water for at least
30 seconds observe the size of the
balloon now this is because the air
inside the balloon is warming up and
expanding just as warm air in the
atmosphere expands gets lighter Rises
and creates a low-pressure area now
let's make a real working barometer
which can measure the same effect in the
atmosphere to build a homemade barometer
you'll need a very large balloon
scissors a large jar with a wide mouth
packing tape a drinking straw
blew some paper a pen a ruler and a
small posterboard triangle cut off the
balloons neck and stretch it over the
mouth of the jar filled the balloon -
the jar was taped and make sure there
are no leaks insert the small triangle
into one end of the strong glue or tape
the other end of the straw to the center
of the balloon lid this will be your
homemade barometer put a piece of paper
on the wall next to your barometers
pointer make a note of where the pointer
falls this is how you can measure the
changes in air pressure check the
position of the pointer every few hours
each time riding down the measurement if
the pointer moves down it's because
there is less atmospheric pressure
pushing down on your balloon barometer
and if the pointer moves up it's because
there is now more atmospheric pressure
pushing down on the balloon
knowing how to accurately measure the
atmospheric pressure is critical to
weather forecasters when the air
pressure is low it generally means bad
weather with storms and precipitation
when the pressure is high it usually
means good weather with clear skies
you know Malcolm if our earth was the
size of an egg then our atmosphere would
only be about as thick as an eggshell
don't start with food analogies I'm
getting hungry again my point is that
our atmosphere as thin as it is can
still be broken down into four main
layers examples