|How does tempature affect air pressure.
|Question Date: 2005-03-30|
In a very simple way. As the temperature
increases, the pressure increases as well. For a
given volume of air (say the air in a car tire)
doubling the temperature doubles the pressure.
Halving the temperature halves the air
pressure.For this simple relation to work, it is
important that you measure the temperature using
special units called Kelvin. Water freezes ar 273
Kelvin, and boils at 373 Kelvin.
You asked a really good question.First, let's
pretend we have a box and in that box we have some
air. Now let's heat up the box. When we heat the
air in the box, the air expands. A bigger volume
of gas inside the box means that the pressure
inside is greater. Conversely, if the temperature
of the gas decreases, its volume will shrink and
the pressure inside the box will go down.
Temperature and pressure are directly related. If
the temperature is high then the pressure is also
high and vice versa. Increasing temperature is a
way of adding heat energy. So if you have a bunch
of particles and you increase the temperature (or
add energy) these particles start moving. When
the particles are moving they will bounce into one
another. This is what increases the pressure.
For example, think of a teapot of water that you
are boiling. You are adding heat to the pot which
will heat up the water. The water molecules
start moving around and smacking into each other
building up their pressure until a point where
they start to evaporate (water vapor or steam)
--the increased pressure and the escaping
molecules are what causes the teapot to
whistle.Another example for the opposite scenario
(decreasing pressure leads to decreasing
temperature) that I can think of: If you were to
take a bottle of soda that was at room
temperature, shake it, and open it..the soda would
be cooler than room temperature. This is because
when opening the bottle the soda (which was under
pressure) there is a decrease in pressure and the
gas that escapes will take the heat with it.
***This would work in a 'perfect'
scenario. In everyday life there are too many
other factors that may come into play which might
prove this to be wrong.
Air pressure is the force exerted on you by the
weight of tiny air particles (air molecules).
Although air molecules are invisible, they still
have weight and take up space. The molecules
expand and contract as temperature increases and
decreases. As the temperature increases, so does
the air pressure. As the temperature decreases, so
does the air pressure.There are mathematical
relationships that establish the behavior of
temperature, pressure, and volume. You will learn
them in High School.
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