Download Densities of Some Solids

Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 1
Date: ____________
Review of 8th Grade Physical Science Content Standards
STANDARD #1: Motion (8 items, 13%)
1) The velocity of an object is the rate of change of its position. As a basis for
understanding this concept:
a) Students know position is defined in relation to some choice of a standard reference point and
a set of reference directions.
b) Students know that average speed is the total distance traveled divided by the total time
elapsed and that the speed of an object along the path traveled can vary.
S=D
T
D=SxT
T=D
S
Average Speed
Constant Speed
c) Students know how to solve problems involving distance, time, and average speed.
S=D
T
Ex Problem: If you traveled a distance of 100 miles & you were going at
an average speed of 50 miles per hour, how long will it take you to get to
your destination?
T = D = 100 mi
S
50 mi/hr
= mile units cancel = 2 hr
http://gmatclub.com/forum/distance-speed-time-word-problems-made-easy-87481.html
d) Students know the velocity of an object must be described by specifying both the direction
and the speed of the object.
V=D
T
Velocity = Speed in a given direction
Ex: 25 miles per hour East
Ex Problem: What is the velocity of a car that traveled a total of 75 kilometers north in
1.5 hours?
V = 75 km = 50 km/hr
1.5 hr
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 2
Date: ____________
Review of 8th Grade Physical Science Content Standards
e) Students know changes in velocity may be due to changes in speed, direction, or both.
Increasing Speed
Decreasing Speed
Changing Direction (Turning)
f) Students know how to interpret graphs of position versus time and graphs of speed versus time
for motion in a single direction.
Time vs. Distance Graph
(stopped)
Speed vs. Time Graph
(increasing) (decreasing) (speed stays the same)
Distance (m)
Time (s)
STANDARD #2: Forces (8 items, 13%)
Weight is Not = to Mass
Not the Same Concept
Newton’s 3 Laws of Motion:
1) Law of Inertia
2) F = M x A
M=F
A=F
A
M
3) For every action there is an equal but opposite reaction (rockets)
2) Unbalanced forces cause changes in velocity. As a basis for understanding this concept:
A Force is a Push or a Pull
a) Students know a force has both direction (the course or line along which something moves,
lies, or points) and magnitude (greatness of size or extent).


b) Students know when an object is subject to two or more forces at once, the result is the
cumulative effect of all the forces.
Like Adding (+) and Subtracting (--) Numbers
Ex: 5 N  + 10 N  = 15 N 
Ex: 5 N  + 10 N  = 5 N 
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 3
Date: ____________
Review of 8th Grade Physical Science Content Standards
c) Students know when the forces on an object are balanced, the motion of the object does not
change.
Ex: 5 N  + 5 N  = 0 N (balanced)
d) Students know how to identify separately the two or more forces that are acting on a single
static object, including gravity, elastic forces due to tension or compression in matter, and
friction.
Ex: Bridges
Air Resistance
Friction: Fluid Friction, Sliding Friction, Rolling Friction, Static Friction
e) Students know that when the forces on an object are unbalanced, the object will change its
velocity (that is, it will speed up, slow down, or change direction).
f) Students know the greater the mass of an object, the more force is needed to achieve the same
rate of change in motion.
More Mass, More Force is required to move it
Momentum = Mass x Velocity
Mo = M x V
g) Students know the role of gravity in forming and maintaining the shapes of planets, stars, and
the solar system.
Centripetal Force
Forward Motion & Gravity due to Centripetal Force
STANDARD # 3: Structure of Matter (9 items, 15%)
3) Each of the more than 100 elements of matter has distinct properties and a distinct
atomic structure. All forms of matter are composed of one or more of the elements. As a
basis for understanding this concept:
a) Students know the structure of the atom and know it is composed of protons, neutrons, and
electrons.
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 4
Date: ____________
Review of 8th Grade Physical Science Content Standards
b) Students know that compounds are formed by combining two or more different elements and
that compounds have properties that are different from their constituent elements.
2H2 + O2  2H2O
(stoichiometry, balanced equation)
c) Students know atoms and molecules form solids by building up repeating patterns, such as the
crystal structure of NaCl or long-chain polymers.
Crystal Structure of NaCl
Example of a Long-chain Polymer
d) Students know the states of matter (solid, liquid, gas) depend on molecular motion.
e) Students know that in solids the atoms are closely locked in position and can only vibrate; in
liquids the atoms and molecules are more loosely connected and can collide with and move past
one another; and in gases the atoms and molecules are free to move independently, colliding
frequently.
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 5
Date: ____________
Review of 8th Grade Physical Science Content Standards
f) Students know how to use the periodic table to identify elements in simple compounds.
1
2
3
4
5
6
7
8
9
NAME
Aluminum
Bromine
Calcium
Carbon
Chlorine
Chromium
Copper
Gold
Helium
SYMBOL
Al
Br
Ca
C
Cl
Cr
Cu
Au
He
10
11
12
13
14
15
16
17
18
NAME
Hydrogen
Iodine
Iron
Lead
Mercury
Neon
Nickel
Nitrogen
Oxygen
SYMBOL
H
I
Fe
Pb
Hg
Ne
Ni
N
O
19
20
21
22
23
24
25
26
27
28
NAME
Platinum
Potassium
Silicon
Silver
Sodium
Sulfur
Tin
Tungsten
Uranium
Zinc
SYMBOL
Pt
K
Si
Ag
Na
S
Sn
W
U
Zn
STANDARD #4: Earth in the Solar System (Earth Science) (7 items, 12%)
4) The structure and composition of the universe can be learned from studying stars and
galaxies and their evolution. As a basis for understanding this concept:
a) Students know galaxies are clusters of billions of stars and may have different shapes.
Shapes: Spiral (We’re in the Milky Way Galaxy. Andromeda Galaxy is the next Spiral us),
Elliptical, Barred Spiral, Irregular
Milky Way
Milky Way Galaxy in Relation to Andromeda Galaxy
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 6
Date: ____________
Review of 8th Grade Physical Science Content Standards
Spiral Galaxy (ex: Milky Way)
Elliptical Galaxy
Barred Spiral Galaxy
Irregular Galaxy
b) Students know that the Sun is one of many stars in the Milky Way galaxy and that stars may
differ in size, temperature, and color.
Hertzsprung-Russell Diagram shows the relationship between the surface temperatures
(x-axis, horizontal axis) of stars & their absolute brightness (y-axis, vertical axis)
http://www.atnf.csiro.au/outreach/education/senior/astrophysics/stellarevolution_hrintro.html
Our Sun is a medium sized star
c) Students know how to use astronomical units and light years as measures of distances between
the Sun, stars, and Earth.
AU = 9 million miles or 150,000,000 Km
Light Year = 300,000 Km/s
Distance of Earth is 1 AU from the Sun
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 7
Date: ____________
Review of 8th Grade Physical Science Content Standards
d) Students know that stars are the source of light for all bright objects in outer space and that the
Moon and planets shine by reflected sunlight, not by their own light.
Stars are Luminescent – they give off light
Moons are just Reflectors of Star light
Remember the song “Twinkle, Twinkle Little Star…”
e) Students know the appearance, general composition, relative position and size, and motion of
objects in the solar system, including planets, planetary satellites, comets, and asteroids.
Sun
Mercury Venus Earth Mars (Asteroid Belt) Jupiter Saturn Uranus Neptune
.39 AU
.72 AU 1.0 AU 1.5 AU
5.2 AU
9.6 AU 19.2 AU
30.0 AU
Way to remember the Planets: My very eager mother just served us noodles (nachos).
STANDARD #5: Reactions (7 items, 12%)
5) Chemical reactions are processes in which atoms are rearranged into different
combinations of molecules. As a basis for understanding this concept:
a) Students know reactant atoms and molecules interact to form products with different chemical
properties.
2H2 + O2  2H2O
Reactants
Product
b) Students know the idea of atoms explains the conservation of matter: In chemical reactions the
number of atoms stays the same no matter how they are arranged, so their total mass stays the
same.
Ex 1:
2H2 + O2  2H2O (stoichiometry)
Mathematically you must have the same number of atoms on both sides of the equation.
Ex 2: The original equation is Na + Cl = NaCl. The thing is, chlorine is one of 7 elements that
doesn't like to be alone, so it's always 'Cl2', making the equation Na + Cl2 = NaCl. However, this
is no longer balanced. So what you do is add a '2' onto NaCl, making it Na + Cl2 = 2NaCl. Now
the chlorine is balanced, but the sodium isn't. After that, to balance the sodium, you add a '2' in
front of 'Na' making the equation 2Na + Cl2 = 2NaCl. It is now balanced.
Ex 3: __ S + __ O2
1S
2O


__ SO3
1S
3O
Unbalanced
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 8
Date: ____________
Review of 8th Grade Physical Science Content Standards
2 S + 3 O2
2S
6O

Ex 4: 1 C3H8 + 5 O2
Ex 5: 1 CH4 + 2 O2
2 SO3
2S
6O


Balanced
3 CO2 + 4 H2O
1 CO2 + 2 H2O
Balanced
Burning of Propane
Balanced
Burning Methane Gas
Get More Practice: http://www.files.chem.vt.edu/RVGS/ACT/notes/scripts/bal_eq1.html
c) Students know chemical reactions usually liberate heat or absorb heat.
Liberate Heat = Exothermic = feels hot
ex: a lit candle
Absorbs Heat = Endothermic = feels cold ex: baking soda & vinegar reaction
In a chemical reaction or change, a new substance is produced. Energy changes occur.
Ex: The brown crust on a toasted marshmallow is the result of sugar changing to a
mixture of different substances called caramel.
d) Students know physical processes include freezing and boiling, in which a material changes
form with no chemical reaction.
Physical Change: A change in a substance that does not change its identity. One or more
physical properties of the material are altered, but the chemical composition remains the
same. In physical change, you can dissolve, bend, crush, break, chop, filtrate, distill, and
anything else that changes only the shape or form of matter.
A physical property is observed with the senses and can be determined without
destroying the object. For example: color, shape, mass, length, density, specific heat and
odor are all examples of physical properties.
e) Students know how to determine whether a solution is acidic, basic, or neutral.
ACID
Hydrogen Ion (H+)
Lost e-, wants to grab an eSour taste
Turns blue litmus paper red
Squeaky clean feel
BASE
Hydroxide Ion (OH-)
Gained an eBitter taste
Turns red litmus paper blue
Slippery feel
STANDARD #6: Chemistry of Living Systems (Life Science) (3 items, 5%)
6) Principles of chemistry underlie the functioning of biological systems. As a basis for
understanding this concept:
a) Students know that carbon, because of its ability to combine in many ways with itself and
other elements, has a central role in the chemistry of living organisms.
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 9
Date: ____________
Review of 8th Grade Physical Science Content Standards
Carbon has 4 Valence Electrons = 4 bonds
b) Students know that living organisms are made of molecules consisting largely of carbon,
hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
Remember, the human body is made of about 99% CHNOPS
c) Students know that living organisms have many different kinds of molecules, including small
ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and
DNA.
A molecule can have as little as 2 atoms and as many as billions of atoms.
Small Water Molecule
Carbohydrate (Glucose) Long Chain
DNA Long Chain
STANDARD #7: Periodic Table (7 items, 12%)
7) The organization of the periodic table is based on the properties of the elements and
reflects the structure of atoms. As a basis for understanding this concept:
a) Students know how to identify regions corresponding to metals, nonmetals, and inert gases.
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 10
Date: ____________
Review of 8th Grade Physical Science Content Standards
Noble Gases = Inert Gases
b) Students know each element has a specific number of protons in the nucleus (the atomic
number) and each isotope of the element has a different but specific number of neutrons in the
nucleus.
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 11
Date: ____________
Review of 8th Grade Physical Science Content Standards
Carbon Isotopes
Periodic Table Trends:
http://www.sparknotes.com/chemistry/fundamentals/atomicstructure/section3.rhtml
c) Students know substances can be classified by their properties, including their melting
temperature, density, hardness, and thermal and electrical conductivity.
Example:
Name: Iron
Symbol: Fe
Atomic Number: 26
Atomic Mass: 55.845 amu
Melting Point: 1535.0 °C (1808.15 K, 2795.0 °F)
Boiling Point: 2750.0 °C (3023.15 K, 4982.0 °F)
Number of Protons/Electrons: 26
Number of Neutrons: 30
Classification: Transition Metal
Crystal Structure: Cubic
Density @ 293 K: 7.86 g/cm3
Color: Silvery
STANDARD #8: Density and Buoyancy (5 items, 8%)
8) All objects experience a buoyant force when immersed in a fluid. As a basis for
understanding this concept:
 Gravity
An object floats when the buoyant force is greater than gravity
 Buoyant Force
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 12
Date: ____________
Review of 8th Grade Physical Science Content Standards
a) Students know density is mass per unit volume. D = M
V
b) Students know how to calculate the density of substances (regular and irregular solids and
liquids) from measurements of mass and volume.
Irregular solids
Use the displacement method and subtract
the difference:
Regular Solids
V=LxWxH
In this example the volume of the object is
2 mL.
c) Students know the buoyant force on an object in a fluid is an upward force equal to the weight
of the fluid the object has displaced.
If an object displaces 5 N of water, then the buoyant force = 5 N
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 13
Date: ____________
Review of 8th Grade Physical Science Content Standards
d) Students know how to predict whether an object will float or sink. (Water =1 g/mL=1 g/cm3)
Density less than 1.0 g/mL will float in water, Density greater than 1.0 g/mL will sink in water.
You can do this by observation, but be careful as some rocks float (pumice) and some woods
sink (cocobolo)
Densities of Some Common Gases
Density of Some Common Liquids
GAS
Air/air
Helium
Hydrogen
Nitrogen
Oxygen
Carbon Dioxide
DENSITY
.0013g/cm3
.0001663 g/cm3
.00009 g/cm3
.001251 g/cm3
.0013 g/cm3
.00195 g/cm3
TYPES OF LIQUID
Rubbing Alcohol
Cooking Oil
Mercury
Gasoline
Sea Water
Corn Syrup
Milk
DENSITY: g/mL or g/cm3
.81 g/mL
.92 g/mL
13.6 g/mL
.66 g/mL
1.03 g/mL
1.38 g/mL
1.03 g/mL
Densities of Some Solids
SOLID
Gold
Lead
Silver
Chromium
Cooper
Iron
Steel
Aluminum
Rubber Washer
Plastic
Water (ice)
Table Salt
Diamond
DENSITY g/cm3
19.3 g/cm3
11.3 g/cm3
10.5 g/cm3
7.14 g/cm3
8.9 g/cm3
7.9 g/cm3
7.8 g/cm3
2.7 g/cm3
1.34 g/cm3
.93 g/cm3
.92 g/cm3
2.2 g/cm3
3.52 g/cm3
SOLID
Titanium
Platinum
Uranium
Wood: Balsa
Wood: Pine
Wood: Redwood
Wood: Mahogany
Wood: Cherry
Wood: Walnut
Wood: Red Oak
Wood: Sugar Maple
Wood: Cocobolo
Wood: Ironwood
DENSITY g/cm3
4.51 g/cm3
21.4 g/cm3
18.7 g/cm3
.11 g/cm3
.36 g/cm3
.40 g/cm3
.45 g/cm3
.50 g/cm3
.53 g/cm3
.673 g/cm3
.689 g/cm3
1.10 g/cm3
1.30 g/cm3
STANDARD #9: Investigation and Experimentation (6 items, 10%)
9) Scientific progress is made by asking meaningful questions and conducting careful
investigations. As a basis for understanding this concept and addressing the content in the
other three strands, students should develop their own questions and perform
investigations. Students will:
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 14
Date: ____________
Review of 8th Grade Physical Science Content Standards
a) Plan and conduct a scientific investigation to test a hypothesis.
Scientific Method: http://www.youtube.com/watch?v=ytX-0nxZUCk
Scientific Method Song: http://www.youtube.com/watch?v=owl6PBo6EIk&feature=related
Steps of the Scientific Method: http://www.youtube.com/watch?v=ig7GNipg0mI&feature=related
Scientific Method Explained: http://www.youtube.com/watch?v=JA3yhdNXiFM&feature=related
 Title
 Statement of the Problem (Purpose / Ask a Question)
 Hypothesis (Form a Hypothesis & Make a Prediction)
 Materials
 Procedure (Conduct an Experiment)
 Results (Collect Data)
 Conclusions (Analyze Data / Information & Draw Conclusion)
 (Repeat the work)
b) Evaluate the accuracy and reproducibility of data.
If you do an experiment, can somebody else get the same results? This is similar to a
good chocolate chip cookie recipe. Any baker who follows the recipe precisely will
come up with great chocolate chip cookies every time because the recipe is a good one.
c) Distinguish between variable and controlled parameters in a test.
Variable – changes
Control – always stays the same
http://wiki.answers.com/Q/How_are_variable_and_controlled_parameters_are_used_in_scientific_experiments
d) Recognize the slope of the linear graph as the constant in the relationship y = kx and apply
this principle in interpreting graphs constructed from data.
Slope = Rise
Run
e) Construct appropriate graphs from data and develop quantitative statements about the
relationships between variables.
Student Name: ____________________________
Mrs. Lee – 8th Grade Physical Science
Page 15
Date: ____________
Review of 8th Grade Physical Science Content Standards
Making Science Graphs & Interpreting Data: http://staff.tuhsd.k12.az.us/gfoster/standard/bgraph2.htm
Answers These Questions About Graph
a) How many total miles did the car
travel?
b) What was the average speed of the car
for the trip?
c) Describe the motion of the car between
5 & 12?
d) What direction is represented by line
CD?
e) How many miles were traveled in the 1st
2 hours of the trip?
f) Which line represents the fastest speed?
f) Apply simple mathematic relationships to determine a missing quantity in a mathematic
expression, given the two remaining terms (including speed = distance / time, density = mass /
volume, force = pressure x area, volume = area x height)
(Memorize these)
S=D
T
D=M
V
F=P
A
V = A x H or V = L x W x H
g) Distinguish between linear and nonlinear relationships on a graph of data.
Linear is straight
Nonlinear is not straight (may be curved or may not have a pattern)