Transcript Fluids and Pressure Note Site

Chapter 3 Section 1
Notes
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Pressure
Pressure is the amount of
force exerted on a given
area
Equation for Pressure
Pressure = Force/ area
•Remember: area is the
number of square units
needed to cover an object
Units for pressure are in Pascals
or N/m²
Solve the following problem:
• Find the pressure exerted by a
3,000 N crate that has an area of
2m2.
Pressure= p
Area= 2m2
Force= 3,000N
• Def: A substance that can easily
change its shape, such as liquids and
gases.
•Def 2: A non-solid state of matter in which
the atoms or molecules are free to move past
each other
1st Imp. Fact: They take the shape of their
container.
•Air and water are
fluids
•All fluids exert
pressure
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Quick Reminder:
The atmosphere is
the layer of
nitrogen, oxygen,
and other gases that
surrounds Earth.
Def: The pressure
Imp. Fact:
caused by the
Atmospheric
weight of the
pressure
is
atmosphere
exerted on
everything on
Earth.
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Atmospheric
Pressure
decreases as
elevation
increases.
Look at pg. 68 in your
text. What does Figure
3 and the paragraphs
beside it tell you about
Atmospheric
Pressure?
Answer question on
blank right side of
booklet.
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Very Low
pressure
Higher Pressure
The whole weather
system is a low
pressure, but it
dramatically
decreases towards
the eye of the
hurricane.
Pressure always
flows from high to
low, which creates
the high velocity
winds.
Barometric Pressure
A barometer
uses pressure
forecast
to operate.
• The barometer is used to
weather.
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• Decreasing barometer means
stormy weather and an
increasing barometer means
warmer weather.
Yes, water pressure increases with depth.
The water that is higher up in the container
does not have as much water above it, so
it does not have as much pressure. This
causes the water to come out of the hole
with less force on the top and more force
on the bottom.
•Water pressure
increases with
depth.
Does the amount of water
determine the amount of
pressure?
• Demonstration….
• No, the depth of the water determines the
pressure, not the amount of water.
How are water and atmospheric
pressure similar?
• Water exerts pressure the same
way the atmosphere does
because they both are fluids.
• Both pressures increase with
depth.
Density- the
amount of matter
in a given volume
How are water and atmospheric
pressure different?
• Water is 1,000 times more dense
than air
• The amount of water does not
determine pressure, the depth
does!
Density- the
amount of matter
in a given volume
C
B
A
Step A: When you exhale, a muscle in your chest
moves upward and decreases the space in your chest.
Step B: The decrease in space causes the pressure in
your lungs to increase. The air in your lungs flows
from a region of high pressure (your chest) to a
region of low pressure (outside your body).
Step C: Exhaled air carries carbon dioxide out of
the lungs.
Where do we have high and low pressure in our
balloon rocket? Label your balloon rocket with high
and low pressure and action and reaction forces.
STOP