Secondary III – Science & Technology
Chapter – 3: Fluids & Pressure
Name: _________________________
Date: __________________
Chapter 3 – Review
1. Fluids
a. Fluids are substances that have the _Capacity to flow_____________ and
____Take the shape of their container___.
b. All ____Liquids_ and _______Gases______ are fluids.
c. Are saltwater and smoke considered fluids? ____Yes___ Why?
____________Because though Saltwater contains solids, it still has the capacity
to flow and takes the shape of its container.
__________________________________________________________________
d. Why are fluids able to flow? ________The particles in liquids and gases are not
held together by the strong forces of attraction that bind solid particles together.
For this reason the particles are able to move around one another and the
substance can flow__________________________________
_
e. Circle all of the substances below that are fluids:
i. Air
iv. Smoke
vii. Saltwater
ii. Water
v. Hair Gel
viii. Salt
iii. Sand
vi. Tooth Paste
ix. Play-Doh
2. Compressible and Incompressible Fluids
a. What is the difference between compressible and incompressible fluids? ______
______Compressible fluids (gases) are able to change their Volume,
Incompressible Fluids (Liquids) cannot ____________
3. What is different about the particles of compressible or incompressible fluids that allow
them to be compressed or not. (you can use a drawing to support your statement) _ The
space between the particles of a compressible fluid (gas) allow them to be compressed
or expand. Incompressible fluids (Liquids) have no space in between the particles and
thus cannot change their volume.
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Secondary III – Science & Technology
Chapter – 3: Fluids & Pressure
Pressure
a. Pressure depends on what two factors?
i. ______Force__ and ________Surface Area_____________________
b. List the true statements: _______i, iv______________
i. Pressure increases as the force applied increases
ii. Pressure decreases as the surface area the force is applied to decreases
iii. Pressure decreases as the force applied increases
iv. Pressure increases as the surface area the force is applied to decreases
c. The formula for finding pressure is: P = F/A
i. Where P = _____Pressure_______,measured in : __Pa___
ii. Where N = ______Force______, measured in: ___N__
iii. Where A = ________Surface Area______, measured in: __m2___
d. Mr. Woody is designing a Hydraulic lift that will need to exert 1000 Newtons of
force. If the piston on the hydraulic lift has a surface area of 0.5 m2 what
pressure will be required on the Hydraulic fluid?
P = ?, F = 1000N, A = 0.5 m2
P = F/A, P = 1000N / 0.5 m2 = 2000 Pa
e. A stool is placed upside down on a table at the end of class. If the seat has a
surface area of 0.15 m2 and is applying 100 Pa of pressure on the table how
much force is being applied?
A = 0.15 m2 , P = 100 Pa, F = ?
F = P x A, F = 100 Pa x 0.15 m2 = 15 N
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Secondary III – Science & Technology
Chapter – 3: Fluids & Pressure
4. Pressure Exerted by Fluids (words: particles, equally, motion, all)
a. Fluids exert pressure ____equally_________ in ___all___ directions because
their _________particles_______ are in constant ______motion________.
5. Pressure exerted by Incompressible Fluids
a. The pressure exerted by incompressible fluids depends what two factors?
i. _______________The mass of the fluid situated above an object
immersed in the fluid (Depth). __________________________
ii. _____The density of the fluid. ___________________________________
____________________________________________________________
b. What are three different instruments used to measure pressure in
incompressible fluids? (See page 75 in textbook)
i. ___________Depth Gauge____________________
ii. ______________U-Shaped Manometer_________________
iii. _____________Tonometer__________________
6. Pressure exerted by Compressible Fluids
a. Pressure exerted by a compressible fluid is determined by the
________Number________ of ______Collisions_____ involving fluid particles.
b. The factor above is determined by 3 other factors, what are they?
i. _________Number of Particles in the fluid______________________
ii. ___________Temperature of the fluid____________________
iii. ______________Volume of the fluid._________________
c. What are three different instruments used to measure pressure in compressible
fluids? (See page 76 in Textbook)
i. ________U – Shaped Manometer_______________________
ii. _________Pressure Gauge______________________
iii. ____________Dial-faced Gauge___________________
7. Volume and Pressure in Compressible Fluids
a. As the volume of a compressible fluid_____Increases___ the pressure decreases.
b. As the volume of a compressible fluid____Decreases____ the pressure increases.
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Secondary III – Science & Technology
Chapter – 3: Fluids & Pressure
c. Describe why a weather balloon bursts after is reaches a certain altitude. (See
page 78 in textbook for help) :__As the balloon rises the atmospheric pressure
around it decreases. This causes the balloon to expand because the air pressure
outside the balloon is no longer pushing back on the air inside it. Eventually the
balloon bursts because it expands too much.
8. Atmospheric Pressure
a. On average atmospheric pressure is measured at ____101.3___ kPa at sea level.
b. Why does atmospheric pressure ______Decrease______ as altitude increases?
___There are fewer particles the higher you go, so there are fewer collisions
between particles, and ultimately a lower pressure. _________________
c. The units used by barometers to measure pressure are: _mm of Mercury__
9. General Principals of Pressure in Fluids
a. 1st Principal: A fluid natural flows from a zone of ___High_____ pressure toward
a zone of ___Low____ pressure.
i. Give two real life examples of this principal being observed/used:
1. ____Inhaling and Exhaling, Pumping of a tire.
2. ________Aerosol cans, fire extinguishers. __________________
b. 2nd Principal: Pressure applied to the surface of a fluid inside a closed container
gets uniformly distributed to every part of the fluid.
i. Where and how is this principal observed in cars? __The brake pedal
compresses a piston which creates pressure in the brake fluid. This
pressure is transferred by the second principal through the brake lines to
the actual brakes. Here the pressure is used to compress the brake pads
and slow the car. ___________________________________________
c. 3rd Principal: A transfer of ____Pressure_ in a fluid can increase the
_______Force__ involved.
i. Hydraulic lifts take advantage of this principal by exerting a weaker force
on a piston with a ____smaller____ (smaller/larger) surface area to
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Secondary III – Science & Technology
Chapter – 3: Fluids & Pressure
create a ______larger________ (smaller/larger) force on a piston with a
larger surface area.
10. Natural Mechanisms
a. When the heart contracts its volume ___decreases______(increases/decreases)
which causes blood pressure to _______increase_______ (increase/decrease).
The blood then flows out of the heart into the arteries, observing the __1st__
principal.
b. When the _____diaphragm___________ contracts the volume of the lungs
______increases_________ (increases/decreases) which creates a zone of
___low____ (high/low) pressure within them. The pressure difference generated
draws air into the lungs, observing the _1st_ principal.
c. Indicate in the boxes the direction of air flow and whether the pressure is high or
low inside the lungs in the diagram below:
d. Wind is generated by ____Atmospheric_______ pressure differences in air
masses. Masses of air travel from areas of ___high____ pressure to areas
____low___ pressure creating wind.
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