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Foldable Activity Using the instructions on page 267 in your textbook on
how to make foldables, write a key term on each front tab, and the definition on the inside (see example that I made up). You will use these throughout the unit to help you answer questions and study, so make sure that they are neat and that you keep them in good shape. Use the back of your textbook and chapter 7 to find the definitions.
Key Terms – Chapter 7 boiling
boiling point
change of state
concentration
condensation
deposition
evaporation
flow rate
fluid
freezing point
gas
kinetic energy
liquid
melting
melting point
particle theory of matter
solid
solidification
sublimation
viscosity
The Particle Theory of Matter (PTM)
PTM... A REVIEWPG. 270
All matter is made up of very tiny particles.
All particles in a pure substance are the same but different from another substance.
PTM… There is space between the
particles.
The particles are always moving. They move faster if they gain energy.
There are attractive forces between the particles. Some strong; some weak.
CAN YOU IDENTIFY THE 3 STATES OF MATTER?
3 STATES OF MATTER... A REVIEW
WRITE THIS DOWN
FLUIDS
Any form of matter that flows.
Since liquids and gases do NOT have a definite shape they are able to flow making them fluids.
WE USE FLUIDS EVERYDAY… Food fluids (water, oil, maple syrup,
honey, etc)
Cleaning fluids and creams
Bodily fluids
Industrial fluids (compressed air in tires, lubricants, etc)
VISCOSITY A measure of a fluid’s resistance to
flow.
The thickness or thinness of a fluid.
A fluid that is viscous is the one that is NOT “runny” (flows slowly).
VISCOSITY& FRICTION?
Friction resists movement.
The greater the friction, the greater the viscosity.
The particles are holding on tightly to each other.
VISCOSITY IS IMPORTANT IN OUR EVERYDAY LIFE.
Questions
P. 272 1-5
P. 285 1-7
FLOW RATE The speed at which a fluid flows from one
point to another.
Slow Medium Fast
Corn syrup Dishwashing liquid Water
FACTORS THAT AFFECT VISCOSITY
Temperature:
As you increase temperature, you decrease a liquid’s viscosity. As you decrease temperature, you increase a liquid’s viscosity.
The opposite is true of gases.
FACTORS THAT AFFECT VISCOSITY
Concentration: The amount of a substance dissolved in a specific volume. Increasing the concentration, increases the viscosity.
Factors that affect viscosity Attractive Forces:
If the attractive forces are strong, it is difficult for the particles to pull away thereby the fluid flows slowly and is more viscous.
Factors that affect viscosity
Particle size:
The smaller the particle size, the faster the fluid flows and is less viscous.
P. 298-299
Questions 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16
DENSITY
Remember from Unit 1…
A measure of the mass contained in a given volume.
A substance with a lower density will float on substances with higher densities.
DENSITY AND THE PTM The PTM states that different substances
have different sized particles.
The PTM also states that there are spaces between the particles.
The greater the spaces between the particles, the less particles therefore the lower the density.
Ex. Water vapour has a lower density than liquid water.
Density and the PTM… In general, gases are less dense than liquids
and liquids are less dense than solids.
Calculating Density You must know the mass and volume
of a substance first.
Mass: the amount of matter in a substance.
Volume: the amount of space occupied by the substance.
To measure the volume of an irregular shape, you will need to determine the amount of water it displaces.
Formula:
Density (D) = Mass (m) ÷ Volume (V)
= Mass (m)
Volume (V)
Volume (V) = Mass (m)
Density (D)
Mass = Density (D) x Volume (V)
SAMPLE PROBLEMS 1. Find the density of a 10g mass of a substance that has
a volume of 2.0 cm³.
D= m D=10g
V 2.0cm³
D=5.0g/cm³
ANSWER: The density is 5.0g/cm3
2. You want to put 10g of salt into a container. What is the volume of the container if the salt completely fills it?
V= m V= 10g
D 2.16g/cm³
V= 4.63cm³
ANSWER: The volume is 4.63cm³.
3. What is the mass of 1500mL of helium?
m= D x V
m= 0.0002g/mL x 1500mL
m= 0.3g
Assignment: Complete the practice problems on p. 312-314
Core Lab 8-2B: Determining Density (p. 316-319)
TEMPERATURE & DENSITY
Increasing temperature will cause the particles in a substance to gain energy, spread out and take up more space.
Results in decreased density.
EXAMPLES/ APPLICATIONS...
Hot air balloons
Warm vs. cool tire pressure
Water in each of its three states (water as a solid is less dense as the particles move apart as they freeze)
Drying wood
Salt water is more dense
Swim bladder (fish)
Submarines
Sample Problems – Use these to CHECK your answers. Remember: the answer is only worth 1 out of 5 marks per
question – you need to show ALL WORKINGS!
p. 312-313:
1. The density of the metal is 2.7 g/cm3. It is aluminum.
2. The density is 1.26 g/mL. It is not water because the density of water is 1.0 g/mL.
3. The density of the gas is 0.002 g/mL, and the gas is probably carbon dioxide.
1. Its volume is 0.50 cm3.
2. The helium would occupy 75 L (75 000mL).
3. The sea water would occupy 243 mL.
p. 314
1. Its mass is 28 g.
2. The copper has a mass of 58 g.
3. The machine oil has a mass of 6.3 g.
p. 323 3.
1. 1.59 g/cm3
2. Lead has the
greater density.
Sample Problems – Use these to CHECK your answers.
Key Terms hydraulic systems
incompressible
mass
neutral buoyancy
pascal
pneumatic systems
pressure
static pressure
unbalanced forces
weight
Archimedes’ principle
average density
balanced forces
buoyancy
buoyant force
compressibility
controlled variable
force
hydraulics
hydraulic multiplication
FORCE
Anything that causes a change in the motion of an object.
A push or pull.
BALANCED FORCES ARE...
1-Equal in strength
2-Opposite in direction
3-No movement
UNBALANCED FORCES ARE...
Unequal in strength
Cause a change in speed or direction
MASS VS. WEIGHT
Mass
Stays the same
anywhere in the universe Measured in
kilograms (kg)
Weight A measure of the push
or pull acting on an object. The larger the force of
gravity, the greater the weight. Measured in Newtons
(N)
BUOYANCY
The upward force on an object submerged in or floating on fluids.
An object that floats has neutral buoyancy.
The amount of buoyant force that would push up against the object immersed in the fluid equals the force of gravity or the weight of the fluid that the object displaces.
Balanced
Unbalanced
DENSITY & BUOYANCY If the density of the
immersed object is greater than the density of the fluid, it will SINK.
If an object weighs the same or less than the water it is displacing, it will float.
WHICH WILL FLOAT? WHY?
1.Wooden boat vs. water logged stick
2.Metal block vs. metal boat
3.A sealed empty water bottle vs. full water bottle
AVERAGE DENSITY The total mass of all substances that make up an object divided by the total volume. If the volume of an object is increased, the average density will decrease
TECHNOLOGIES DEVELOPED Personal floatation devices
Submarines
Hot air balloons
Questions page 347
Answers questions 1 to 7 & question 9.
PRESSURE The force acting on a certain area of
surface.
The larger the force, the greater the pressure.
The smaller the area, the greater the pressure.
CALCULATING PRESSURE
The unit for pressure is the Pascal (Pa)
You can determine pressure if you know the force and the area.
Formula: Pressure (P) = Force (F)
Area (A)
SAMPLE PROBLEMS 1. An aquarium is filled with water that
weighs 10 000N. If the base of the aquarium has an area of 1.6 m², what pressure does the water exert on its base?
2. If the atmospheric pressure is 101 200 Pa and you are holding your hand, the atmosphere is exerting a force on your hand. If the area of your palm is 0.006m², calculate the force on your hand.
3. The weight of water in a glass is 4.9 N. If the water is exerting a pressure of 1700 Pa on the bottom of the glass, what is the area of the bottom of the glass?
DETERMINE WHY... 1. A person wearing
snowshoes can walk across a section of deep, soft snow without sinking
2. The nozzle on a garden hose can be used to create a faster or slower flow of water.
ATMOSPHERIC PRESSURE
The pressure exerted by the layers of air surrounding the Earth that are held by the Earth’s gravity. (~ 160 km above the Earth)
PASCAL’S LAW Pressure applied to a enclosed fluid
is transmitted with equal force throughout the entire container
Basis for hydraulic and pneumatic devices.
HYDRAULICS
The study of pressure in liquids.
Hydraulic systems: devices that transmit applied force through a liquid to move something else.
•Hydraulic systems use
liquids because they are
incompressible(they cannot
be squeezed into a smaller
volume).
•The liquid must be enclosed
in a tube or pipe.
•The pressure produced
will exert in all directions
equally.
•This pressure will
cause motion at the
other end of the
hydraulic system.
PNEUMATIC SYSTEMS A gas is used to
exert a force on the gas in an enclosed space.
Pneumatic systems need compressors because gases can be compressed. This builds up air pressure.
PRESSURE & VOLUME Increasing pressure of a fluid will decrease volume by
the same amount.
**known as Boyle’s Law
TEMPERATURE & VOLUME
Increasing
temperature
will increase
the volume
of a fluid.
TEMPERATURE & PRESSURE
Increasing temperature of a fluid will increase the pressure.
In other words… If the temperature of a fluid is constant (not changing)…
If the pressure of a fluid is constant…
T = V
T = P
P = V
If the volume of a fluid is constant…
Why does this symbol appear on aerosol cans?
Questions in Textbook pages 380-383
Answer all questions
Except for: 16, 38, 39, 40, & 41
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