NAME ______DATE______PER.______

CRCT STUDY GUIDE

Science

Grade: 8

Domain: Structure of Matter

Domain Description

Structure of Matter refers to distinguishing between atoms and molecules, pure substances and mixtures,physical and chemical properties, and physical and chemical changes in matter. This domain also refers tounderstanding the organization of the Periodic Table of Elements and explaining the Law of Conservationof Matter.

• Compare and contrast atoms and molecules

What are pure substances? Substances thatcannot be separated into any other kinds of matter by any physical or chemical process. It is also made up of the same particles.

Describe elements, compounds, and mixtures.(Be sure to draw a picture of each):

Explain the difference between pure substances and mixtures.(Include an example and definition in boxes).

• Describe and draw the movement of particles in different states of matter, such as:

Describe: / Draw:
solid /
  • Definite Shape; Definite Volume
  • Particles are tightly packed
  • Vibrate back and forth

liquid /
  • Definite Volume; No Definite Shape(Takes the shape of container)
  • Particles move freely; stay close to each other

gas /
  • No definite shape or volume
  • Loosely packed;
  • Particles move at high speeds

plasma / Atoms are stripped of the electrons; occurs at extremely high temps. And extremely fast particle movement

What are Physical and Chemical Properties?

• What are the following physical properties of matter? (Define)

Density / Mass per unit volume( I LOVE density) D =
Melting Point / The temperature at which a solid changes to a liquid
Boiling Point / When a liquid is heated, it eventually reaches a temperature at which the vapor pressure is large enough that bubbles form inside the body of the liquid.

•What are the following chemical properties of matter?(Define)

Reactivity / the ease and speed with which an element combines,or reacts, with other elements and compounds
Combustibility / how readily a substance is able to react with oxygen within the air.

• What are someother physical properties and chemical properties of matter not listed above?

Physical Properties / Chemical Properties
Color
Solubility
Freezing point
Hardness / Flammability
Reacts with an acid to form hydrogen
Reacts with water to form a gas

• What are physical changes and chemical changes in matter?

Examples of Physical Changes / Examples of Chemical Changes
Ice melts
Grinding Baking soda into powder
Bending an iron nail / Souring milk
Burning paper
Mixing vinegar and baking soda

• How is the periodic table organized?

Periods: (Rows) Arranged by increasing atomic number ( # of protons, which equals electrons)

Groups:( or FAMILIES) columns; families have similar chemical and/or physical characteristics; same number of valence electrons

What elements are categorized as metals, nonmetals and metalloids? Color and labelthe periodic Table to show each (Include: Noble Gases)

• What is the Law of Conservation of Matter? Give examples.

Law of Conservation of Matter(Define) / Examples
Matter can neither be created nor destroyed in a chemical reaction / During a chemical reaction, the reactants must equal the products;
Take the example of burning a piece of paper. It seems that the mass shrinks as the paper burns. However, what is really happening is that the paper is changing form to ash, carbon dioxide, and water vapor.
If you could capture all of those bits during the burning, they would have the same mass as the paper itself.
  • Label the Products and Reactants in the following chemical equation

C + 2C +

____Reactants______Products______

How many atoms of each element are on each side of the chemical equation?

C = ____1______

H = _____4_____

O = ____2______

C = ___2______

H = __2______

O = ___5______

Is the equation balanced? ____NO; # of atoms on each side of the equation for each element is different______

Science

Grade: 8

Domain: Force and Motion

Domain Description

Force and Motion refers to describing the relationship between force, mass, and the motion of objectsincluding the effects of simple machines. This domain also refers to explaining the relationship betweenmass and gravity, comparing and contrasting series and parallel circuits, and recognizing that electriccurrents and magnets can exert force on each other.

What is the relationship between velocity and acceleration?

  • Acceleration is the rate at which velocity changes.
  • Velocity is speed of an object in a particular direction
  • Velocity changes if:
  1. Speed changes
  2. Direction changes
  3. Both speed and direction changes
  • So an object accelerates if its speed, direction or both change.

What is the formula for the following terms?

Formulas / Write out the variables involved.
Speed / V = / d = distance (meters); t = time( second)
Velocity / V =
Acceleration / A = vf – vi
Δt / vf = final velocity vi = initial (starting)velocity
Δt = change in time Unit = m/s2 or m/s/s

Distance-Time Graph / Velocity-Time Graph
Measures:Speed/Displacement / Measures:Acceleration
Leg 1: Moving away from starting point / Leg 1: Positive Acceleration
Leg 2: Not moving ; Stationary / Leg 2: Constant Velocity
Leg 3: Moving toward starting point / Leg 3: Negative Acceleration (Deceleration)
Leg 4: Moving away from starting point / Leg 4: Positive Acceleration
  • Give 2 examples of balanced and unbalanced forces:

Balanced Examples
A clock on a wall / Unbalanced Examples
A moving car
A person sitting in a chair / A see saw

What are Newton’s three laws:

1st: Law of Inertia-An object in motion will stay in motion and an object at rest will stay at rest unless acted on by an unbalanced force

2nd: F = ma; The difference in forces would be caused by the different masses of objects; Greater the mass, the greater the force needed to accelerate

3rd:Action/Reaction: For every action there is an equal and opposite reaction.

Give an example of each law:

1st:Inertia: If you were not wearing your seatbelt and you were traveling very fast, your body could continue to move forward through the windshield.

2nd:F = ma; More force would be needed to throw or stop a bowling ball than a ping pong ball.

3rd:Action/Reaction: The force of gases pushing against the surface of the earth is equal and opposite to the force with which the rocket moves upward

• Explain the effect of forces (gravity and friction) on the motion of an object:

Gravity – The force of attraction between any 2 masses

  • Law of Universal Gravitation – Gravity is affected by Mass and Distance
  • Gravitational Acceleration – All objects fall to the Earth at the same rate (9.8 m/s2)

Friction- A force that opposes motion between 2 surfaces that are in contact

  • The texture of the surface affects the amount of friction
  • Smoother surfaces reduce friction; rough surfaces slow objects down due to friction

• Give examples and draw the following simple machines:

Lever / 1st Class / Fulcrum is in the middle
Ex: see saw
REMEMBER:
F
L
E / 2nd Class / Load is in the middle
EX: Wheelbarrow
3rd Class / Effort is in the middle
EX: broom

• How and why does every object exert gravitational force on every other object:

All objects have a force of attraction that attracts objects to other objects

• What are the factors that determine the gravitational force exerted on objects:

Mass and distance

• Describe the advantages and disadvantages of series and parallel circuits:

How do series and parallel circuits transfer energy differently?

* see Venn Diagram

Draw a picture of a series and parallel circuit:

SERIESPARALLEL

How do electric currents and magnets exert force on each other? Put the correct phrases in the appropriate boxes. Two opposite charges attract, N attracts S, + attracts -, like poles repel, like charges repel, two opposite poles attract, can be used to make electricity, can be used to make magnetism

Science

Grade: 8

Domain: Energy and its Transformation

Domain Description

Energy and its Transformation refers to understanding the Law of Conservation of Energy, the

relationship between potential and kinetic energy, comparing and contrasting forms of energy, anddescribing how heat is transferred. This domain also refers to investigating light, sound, electromagnetic,and mechanical waves.

What is the Law of Conservation of Energy?

Energy cannot be created or destroyed, but changes from one form to another.

Describe the relationship between potential and kinetic energy:

Determine if the following examples are KE (Kinetic Energy) or PE (Potential Energy)

__KE______A car is traveling 45 mph.

__PE______A rock is on a ledge 5 meters high.

___PE_____ A car is resting at the top of a hill.

__KE______A ball is thrown into the air and is still moving.

__KE______A ball rolling on the ground.

Give 5 real world examples of each type of energy:

○ heat: Heat flows from High temperature to low temperature (melting ice)

○ light: Any object in which the electrons are bombarded (lamp)

○ electricity: An object that has an electric charge (refrigerator, heater)

○ mechanical motion: Combination of potential and kinetic energy (kicking a ball, roller coaster)

○ sound: Vibration of molecules through a medium (I-pod, radio, musical instrument)

Describe the transfer of heat by different processes, such as:

What are the characteristics of electromagnetic and mechanical (sound) waves

What is another name for light and sound waves?

Light: Electromagnetic Wave

Sound: Mechanical (Longitudinal Wave)

Label the different types of electromagnetic waves in the boxes below.

•

Describe how the behavior of light waves is manipulated in different processes:

reflection / Bounces off the surface at the same angle it hit with
refraction / Travels through material, but at an altered bent angle
diffraction / Travels through the material until it encounters an obstacle or hole, which it bends around or goes through
absorption / Cannot travel all the way through the material

Explain how the human eye sees objects and colors in terms of wavelengths:

Colors /
  • The color appearance of any object is due to the wavelengths of light that are reflected from the object and picked up by our eyes.
  • Black objects absorb all the colors of the visible spectrum.
  • White objects reflects all the colors of the visible spectrum.

Wavelengths / Light waves in the visible spectrum are arranged from longest (red) wavelength to shortest wavelength (violet).

• Describe how the behavior of waves is affected by medium:

air / The particles of a gas a farther apart making the transferring of energy harder to
water / The particles are closer together in liquids and solids making the transmission of energy easier
solids

Relate the properties of sound to the following everyday experiences

  • Doppler Effect: Doppler Effect is the sudden change in pitch caused by a shift in frequency and wavelength of waves which results from a source moving with respect to the medium (Hearing a police siren pass by)
  • The sound from fireworks not matching what you see: Light Waves travel faster than sound waves.

Explain how the parts of a wave are affected by changes in amplitude and pitch

Amplitude / Amplitude is the height of the wave.
The amplitude of the wave measures the loudness of sound waves.
Larger amplitude = Louder sound
Pitch / The frequency determines the pitch of a sound wave.
Higher frequency = higher pitch

Identify the parts of a wave using a diagram.

1. _____Transverse Wave______