Transcript Physical Sci MCAS Review

Mrs. McCarthy’s
MCAS Review
Physical Sciences
• 8th Grade Curriculum
–Properties of Matter
–The Atom
–Elements, Compounds, and Mixtures
–Motion
–Forms of Energy & Heat
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Particle Motion & Phase Changes (15)
Mass vs. Weight (1)
Volume vs. Mass; Density (2)
Measuring Tools (3)
Conservation of Mass (4)
Melting Point & Boiling Point (9)
Physical & Chemical Changes (10)
Solid
• Has a definite shape and a definite volume
• Particles are held tightly in place and
vibrate in place
Looks Like
Liquid
• Have a definite volume and no definite
shape
• Take the shape of a container
• Can Pour
• Particles slide past one another
Looks Like
Gas
• Have NO Definite Shape or Volume
• Fill their containers
• Particles spread out and move
independently
Looks Like
Plasma
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Very high in energy
Plasma has no definite shape or volume
Particles are broken
Plasma is the most common phase of
matter in the universe
• Examples: Auroras, lightning, fire, neon
lights
Charles’ Law
• The volume of a gas increases as its
temperature increases
• For Example:
– A balloon expands and pops when it is
heated.
– A balloon contracts and gets smaller when it
is cooled.
Boyle’s Law
• The volume of gas increases as the
pressure decreases
• Example: Piston
– Lifting the Plunger Decreases the Pressure
– Pushing the Plunger Increases the Pressure
States of Matter
Matter changes
phases due to a
change in the
heat energy of an
object’s particles.
Solid
Phases
Changes
Add Energy/Heat 
Liquid
Gas
Lose Energy/Heat ←
Measurement
• Mass
• Weight
• Volume
• Temperature
Mass
• The amount of matter in an object
• Doesn’t change with gravity
• Measured with a triple-beam balance
• SI unit of grams
Inertia
• A resistance to a change in motion
• The more mass an object has, the more
inertia it has
• Example: Grocery Carts & Cars
Weight
• The amount of gravitational pull on an
object
• Changes with gravity
• Measured in Newtons
Volume
• The amount of space an object takes-up
• Can be measured with a ruler using the formula:
Volume = length * width * height
OR
• Volume can be measured with water and a
graduated cylinder using displacement
• Solid SI Unit of cm³
• Liquid SI Unit of mL
Density
• The amount of mass in a given volume
• Measured with the Formula:
Density = Mass / Volume
Mass
______________
Density * Volume
* Labeled
in g/cm³
Density Stackers
• Many liquid mixtures will stack up into
layers by their densities
– More dense materials will be below less
dense materials
– Example:
Salad Dressing
Characteristic Properties
• Describe substances based upon their
characteristics
• Example:
Physical Properties
Chemical Properties
Physical Properties
• Physically describe an object based upon
observable and measurable observations
Examples:
COLOR
Mass
Volume
Weight
Boiling
Density
Malleability
Temperature
Ductility
Solubility
Texture
State
Melting
Melting Point &
Boiling Point
• Each Substance has its own Melting &
Boiling Points that are always the same
temperature regardless of the size
Particle Motion &
Temperature Increases
• Melting- the change from a
solid to a liquid
• Adding energy
• Boiling- the change from a
liquid to a gas
• Adding Energy
Melting & Boiling Points
• Melting Point:
All Water Melts
at 0˚C
• Boiling Point:
All water boils
at 100˚C
Physical Changes
• A change in a substance that affects one
or more physical properties of a substance
• The substance does not change
• Examples:
Cutting Hair
Crushing a Can
Sanding Wood
Broken Glass
Melting Butter
Freezing Water
Dissolving Salt
Bending Metal
Chemical Properties
• Describe substances based upon their
ability to change into a new substance with
different properties
• Chemical properties are not easily observed
with your senses and often need to be tested
• Examples:
Reactivity: Tarnishing, Rusting,
Flammability
Chemical Changes
• When substances change into new
substances with different properties
• Examples:
Reactivity
Gas Formation
& Bubbles
Burning
Cooking
Conservation of Mass
• Mass cannot be created or destroyed
• Even during a chemical reaction, the
mass will remain the same.
• Example- Lab with: Vinegar, Baking
Soda, Baggies, Film Canister, & T.B.B.
Before
After
• There are more than 100 elements on the
periodic table that make up ALL things (5)
• Atoms of Elements vs. Molecules of
Compound (6)
• Examples of Elements and Compounds
(7)
• Mixtures vs. Pure Substances (8)
Atomic Theory
• Democritus- Proposes the Atom 440 B.C.
• Dalton- Atoms are the Smallest Particle
• Thomson- “Plum Pudding” with Electrons
• Rutherford- Gold Foil → Atom’s Nucleus
• Bohr- Electrons Travel in Energy Paths
• Schrödinger & Heisenberg- Electron Clouds
Atom
• The Smallest Unit of an Element
• Everything is made of Atoms
Energy
Levels
Nucleus
with
Protons
and
Neutrons
Electrons
Protons
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Charge: Positive
Mass:1 amu
Location: Nucleus
Proton count determines the element
Protons = atomic number
Neutrons
Charge: none
Mass: 1 amu
Location: Nucleus
*To find the neutrons: atomic mass – atomic
number
Electrons
• Charge: Negative
• Mass: Almost Zero
• Location: Electron Clouds
• Balanced Atoms: Protons = Electrons
Periodic Table
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Organized Data of Elements
Organized by Atomic Number
Over 100 Elements
Contains Many Patterns
Element Cube:
2
Atomic Number
He
Chemical Symbol
Helium
Element Name
4.0
Atomic Mass
Pure Substances
• A substance with only one type of particle
• Examples: Elements & Compounds
• Pure Substances Cannot be Broken
Down and Retain their Properties
Elements
Elements
Metals
Shiny, Strong
Conductors,
Malleable, Ductile
Left of zigzag line
Nonmetals
Dull, Poor
Conductors, Brittle
Metalloids
Semiconductors,
Have Properties of
Metals & Nonmetals
Right of zigzag line Border the zigzag line
Mixtures
• A combination of two or more substances
that are not chemically combined.
• A mixture is easily separated by physical
means
• A mixture is NOT a pure substance.
Separating Mixtures
Techniques:
- Magnet: uses a magnet
- Filter: uses a sifter
- Centrifuge: uses spinning (densities)
- Solutions: uses dissolving
- Distillation: uses boiling point
Chemical Reactions
• The process where one or more
substances changes to become one or
more different substances.
• LAW OF CONSERVATION OF MASS
– Mass is never gained or lost in a chemical
reaction
Clues to Chemical Reactions
• Gas Formation
• Solid Formation
• Color Change
• Energy Change
Chemical Formulas & Equations
• A chemical formula uses symbols and
numbers to represent a compound
• Chemical Equations uses formulas and
symbols to show a chemical reaction
– Chemical Equations MUST be Balanced and
follow the Law of Conservation of Mass
Example:
C + O2  CO2
• Motion is described by
Position, Direction, & Speed
• Graphs of Distance vs. Time
(S= D/T)
Motion
A change in an object’s position
relative to reference point(s)
during a specific length of time
Distance
Speed * Time
Velocity
Speed an object travels in a given direction
The unit label is ALWAYS a: Distance/Time &
Direction Word
Example: 60 miles/hour West
Example Direction
Words: North, South,
East, West, Left, Right,
Up, Down
Force
•A push or a pull
•Exerted on one object
by another object
•Can affect an object’s
speed or direction
Unbalanced forces
If the net force on an object is
NOT ZERO.
The resulting effect is the
object changes its motion.
Balanced forces
If the net force on an object
is ZERO
the resulting effect is the
object has
NO change in its motion.
Friction
•Resists Motion Between 2
Objects
•Dependent on Texture of
Surfaces
•4 major types: Rolling, Sliding,
Static, Fluid
GRAVITY
Gravity is a force of attraction
• Exists between any two objects
•The force is
dependent upon
The size of the
objects and the
distance they
are from one
another
Law of Universal Gravitation
•The force of Gravity is
dependent upon the size of the
object and the distance they
are from one another.
Gravitation force increases
• as masses increase
• as the distance decreases
•Bigger & Closer
Gravitation force decreases
• as masses decrease
• as the distance increases
•Smaller & Farther
•Weight is a measurement of
a planet’s gravitational pull
on the mass of an object.
•Therefore, weight is
different on different
planets and
other
celestial
Mass vs. Weight
• Measured
with a triple
beam
balance.
• Measured
with a
Newton
spring
scale.
• Acceleration is the rate at which
velocity changes.
• Gravity causes all objects, regardless
of size, to fall at the same
acceleration
• On Earth, all objects fall at a rate of
9.8 m/s/s
Projectile Motion
Occurs when an object has
two forces acting on it:
gravity &
a push-horizontal- force.
The result is a curved path
• Potential Energy vs. Kinetic Energy and
Energy Changes (13)
• Heat is Energy that causes temperature
changes (14)
• Heat causes Phase Changes (15)
• Heat moves from warmer objects to
cooler objects (16)
Different forms of
Energy
Heat/Thermal
Nuclear
Light
Chemical
Elastic
Sound
Electromagnetic
•Energy
•the ability to do work
•Work occurs when an
object moves in the
direction of the applied
force
Energy, like work, is measured in
joules (J).
Energy exists in many different forms
and can change between them:
Energy conversion
Energy transformation
Types of Energy
• Potential
Energy:
–Stored Energy
• Kinetic
Energy:
–Energy of
Motion
Energy Changes
• Energy can be Transferred
between Potential Energy and
Kinetic Energy
Law of Conservation of
Energy
Energy can not be
created or destroyed.
It can change forms.
Heat
Heat is a form of thermal energy.
Heat is Energy that causes temperature
changes.
Each Substance has unique Melting and
Boiling points.
Heat Changes Particle Motion and Causes
Phase Changes.
Heat Moves from Warm Objects to Cooler
Objects.
Temperature
• Temperature is a Measurement of Heat
• Temperature is Measured with a Thermometer
• Temperature Scales:
– Celsius (˚C)
– Fahrenheit (˚F)
– Kelvin (k)
Melting Point &
Boiling Point
• Each Substance has its own Melting &
Boiling Points that are always the same
temperature regardless of the size
Particle Motion &
Temperature Increases
• Melting- the change from a
solid to a liquid
• Adding energy
• Boiling- the change from a
liquid to a gas
• Adding Energy
Melting & Boiling Points
• Melting Point:
All Water Melts
at 0˚C
• Boiling Point:
All water boils
at 100˚C
States of Matter
Matter changes
phases due to a
change in the
heat energy of an
object’s particles.
Solid
Phases
Changes
Add Energy/Heat 
Liquid
Gas
Lose Energy/Heat ←
Heat Transfer
• Heat moves in predictable
ways from warm objects to
cooler objects
Heat energy moves in three ways:
Conduction
Convection
Radiation
Conduction :occurs
when energy is
passed directly from
one item to another
Convection
Convection : movement of
gases or liquids from a
cooler spot to a warmer
spot.
Examples- Air Masses,
Earth’s Mantle; Ocean
Convection : movement of FLUIDS
(GAS OR LIQUID)
from a cooler spot to a
warmer spot.
WIND
EARTH
BOILING
Radiation :The sun's rays
travel in straight lines called heat
rays. When sunlight hits the
earth, its radiation is absorbed or
reflected.
Darker surfaces absorb more of the
radiation and lighter surfaces reflect the
radiation.