March 2013
Science Mock
STAAR Test
th
8 Grade
1. How many different elements are involved in the reaction shown
above?
All element symbols start
with a capital letter. The
elements in this reaction
are carbon, hydrogen, and
oxygen. There are the same
exact 3 elements on the
products side as there are
on the reactants side.
3
2. Which of these best describes one of the subatomic particles that
could be found at location X in the model of an atom shown above?
F.
G.
H.
J.
It has mass but no charge.
It has no mass and a positive charge.
It has a large mass and a negative charge.
It has no mass and an equal number of positive and negative charges.
Location X is the nucleus. In the nucleus are two particles.
One is the proton. It has mass and is positively charged.
The other is a neutron. It has mass and has no charge. The
electrons, which are negatively charged are NOT found in
the nucleus.
3. An element has a metallic-gray appearance. It also has the properties
of both a metal and a nonmetal. In which section of the periodic table
indicated above would the element most likely be found?
A. 1
B. 2
C. 3
D. 4
Elements having properties of both a metal and a nonmetal
are metalloids. Metalloids are found on the “staircase”
between the metals and the nonmetals.
4. A student observes some sugar as it is heated and burns. The
student concludes that a chemical reaction has occurred. Which of
the following observations about the burning sugar provides evidence
of a chemical reaction?
F. Heat is added to the sugar crystals.
G. The sugar melts and becomes a liquid.
H. The temperature of the sugar increases.
J. Gas is produced as the sugar turns black.
Indicators of a chemical change/reaction include:
• temperature change (but not due to external heating)
• color change
• light production
• gas production
• precipitate formation
Change in state of matter is NOT an indicator of a chemical change.
5. In the diagram above, a wind turbine is transforming energy from the
wind. Between which two steps in the diagram is mechanical energy
being converted into electrical energy?
A. 1 and 2
B. 2 and 3
C. 3 and 4
D. 4 and 5
Mechanical energy is a form of energy that moves objects.
Electrical energy is the presence and flow of an electric
charge, usually through wires.
6. In a series of controlled experiments, a student measures the force
acting on a wheeled cart and the cart’s acceleration. The student’s data
are shown below. Based on the recorded observations, what is the mass
of the cart in kilograms?
F
m a
Choose any force with its
acceleration.
If F=ma, then m=F/a
m=?
F=20
a=1.0
m=20/1=20
Force = mass * acceleration
2 0
7. A toy train engine rests motionless on a track. One student begins
pushing the engine to the right with a force of 2 newtons. At the same
time, another student begins pushing the engine to the left with a force
of 5 newtons. Which of the following best describes the resulting
motion of the engine?
A. It travels left at a constant speed.
B. It travels left at an increasing speed.
C. It travels right at a constant speed.
D. It travels right at an increasing speed.
Newton’s 2nd Law of Motion states that unbalanced forces
cause objects to accelerate in the direction of the greater
force.
8. The diagram above shows the orbit of the moon around Earth. At
which point in the moon’s orbit will a person standing on Earth see a
waxing crescent moon?
F. 1
G. 2
H. 3
J. 4
When the moon is between the Earth and Sun, it is a new
moon. As it revolves counterclockwise, it begins to wax (or
more of the lit portion is visible. When it is on the other
side of the Earth, it is a full moon and then begins to wane
(or less of the lit portion is visible.) Halfway between each
of these stages is a quarter moon.
9. Earth’s land areas, oceans, and atmosphere maintain fairly constant
average temperatures. What is the best explanation for these constant
average temperatures?
A. Earth’s Northern Hemisphere and Southern Hemisphere have
opposite seasons.
B. Earth is tilted and rotates daily on its axis.
C. The continuous motion of air and water distributes the sun’s energy.
D. Global weather systems generally move from west to east.
The sun provides energy that drives convection within the
atmosphere and oceans, producing winds and ocean
currents.
10. The high winds of hurricanes
and typhoons often destroy
mangrove forests. The
destruction of these forests most
likely affects ecosystems by —
F. reducing beach erosion in sea-turtle nesting areas
G. reducing the amount of saltwater flowing into lakes
H. causing pollution in inland rivers and streams
J. forcing migratory birds to find other places to rest
If the mangrove trees were
destroyed, there would be more
beach erosion and less area for
wildlife to be.
11. A diagram of a plant cell is shown below. The function of the plant
cell structure shown in the enlargement is to —
A. provide support for the cell
B. direct all the cell’s activities
C. use energy from sunlight to make sugar
D. regulate substances that enter and exit the
cell
•Cell support is provided by the cell wall and it surrounds the entire
cell.
•The nucleus directs the cell’s activities and there is only one per cell.
•The chloroplasts use energy from sunlight to make sugar and there
are several of those in plant cells.
•Substances entering and exiting the cell are regulated by the cell
membrane which surrounds the cell.
12. Eukaryotes are classified into four kingdoms according to certain
characteristics. The diagram below shows some characteristics of the
four kingdoms. Which of these is the plant kingdom?
F. Kingdom 1
G. Kingdom 2
H. Kingdom 3
J. Kingdom 4
Plants are organisms that have many cells and make their
own food. Multi- means many and Uni-means single or
one. Autotrophic means makes own food. Heterotrophic
means gets food by consuming other organisms.
13. A drain cleaner consists of sodium hydroxide and aluminum. When
the drain cleaner is added to water, bubbles of hydrogen are produced,
and the solution becomes very hot. Which of these best describes
what happens to form the bubbles when the cleaner is added to
water?
A. A chemical reaction
B. Condensation
C. A physical change
D. Evaporation
Bubbles can indicate gas production which can indicate a
chemical change. Condensation is the change from a gas to
a liquid. Evaporation is the change from a liquid to a gas. A
physical change is a change in a physical property that does
not create new substances.
14. In the picture above, a boy is trying to pull a dog
on a leash, but the dog and the boy are moving in
the same direction. Which of the following best
describes the forces in this situation?
F. The forces are balanced, and the net force is zero.
G. The forces are unbalanced, and the boy’s force is greater.
H. The forces are unbalanced, and the dog’s force is greater.
J. The forces are balanced, and the dog is stronger than the boy.
Newton’s 2nd Law of Motion states that unbalanced forces cause
objects to accelerate in the direction of the greater force.
15. Nicholas and Zach were playing darts, as
seen above in the picture. If the dartboard
represents an atom, which dart would indicate
a positively charged region?
A.
B.
C.
D.
dart W
dart X
dart Y
dart Z
The nucleus contains protons (+) and neutrons (Ø) and is located in
the center of the atom. The electrons (-) are located in the electron
cloud outside of the nucleus.
16. A gasoline-powered vehicle goes up a hill from point X to point Y.
What energy transformation must occur in the car’s engine?
F. Chemical energy into mechanical energy
G. Electrical energy into chemical energy
H. Heat energy into chemical energy
J. Mechanical energy into nuclear energy
• Chemical energy is a form of potential energy in foods and fuel. It is
released through chemical reactions such as digestion and combustion.
• Mechanical energy is a form of energy that moves objects.
• Electrical energy is a form of energy that is present and flows through
electrical charge.
• Heat energy is caused by the increase of speed in molecules.
• Nuclear energy is energy associated with atomic reactions.
17. The table above shows where some birds
in a Texas ecosystem are located within the
layers of plants in their environment. These
layers begin at the ground and end in the area
above the treetops. Which of these would
most likely occur if a wildfire destroyed all the
plants in the lowest level of this ecosystem?
A. Vireos would begin to nest on the ground.
B. Doves would have to move to a different area to find food.
C. Hawks would begin to hunt for animals in the middle level.
D. Cardinals would move to above tree level and begin competing with
hawks.
Animals’ habitat affected by the wildfire would have to adapt what
they did to get food and shelter, but would not make an extreme
change. Animals not directly affected by it would not make much, if
any, change in their food and shelter.
18. Which process below uses carbon dioxide and the sun’s radiant
energy to produce chemical energy?
F. Evaporation
G. Photosynthesis
H. Respiration
J. Decomposition
• Evaporation-changing from liquid to gas
• Photosynthesis-carbon dioxide + water and light yields
oxygen and glucose (food for the organism)
• Respiration-ridding the organism of waste materials
• Decomposition-breaking down of molecules into simpler
substances
19. The series of pictures shows a view of the
moon from the same position on Earth on
different days of one month. The pictures
show that on certain nights the moon —
A.
B.
C.
D.
moves away from Earth
receives less light from Earth
is unlit as viewed from Earth
makes half a turn around Earth
Phases of the moon occur because the moon revolves
around the Earth, taking approximately one month. As it
moves around the Earth, we can different amounts of the
lit portion including times where we see all of the lit
portion and other times where we seen none of the lit
portion.
Measures 5.5 &
8.2 cm
20. The scale drawings above show two
catfish collected from a river. What is the
difference in the actual body lengths of
these catfish?
•Find scale measurement, subtract,
then multiply difference by scale
value.
•Scale is 1 cm = 4 cm
• 8.2-5.5= 2.7 cm
• 2.7 cm * 4= 10.8 cm
1 0
8
21. Water, H2O, is classified as a(n) –
A.
B.
C.
D.
colloid
compound
element
mixture
A compound is a molecule made up of more than one
element. Water is made up of hydrogen and oxygen.
F. 6 m/s
G. 8 m/s
H. 24 m/s
J. 72 m/s
22. Sally was trying to calculate the speed of the
hummingbirds feeding outside her window. Sally
measured the distance from one feeder to the
next, 24 meters. Then she sat and timed how
long it took a hummingbird to fly from one feeder
to the next. She timed 10 trials and calculated
the average time, 3 seconds. What was the
average speed of the hummingbird flying from
one feeder to the other?
Speed = distance/time
S=?
d = 24 m
t=3s
S = d/t
S = 24 m/3s
S = ___ m/s
23. Which of these best explains why the oceans have a great impact
on the weather over the continents?
A. Ocean waves move more easily than continental rock.
B. The oceans contain a wider variety of organisms than the continents.
C. The oceans store and transfer more heat than the continents.
D. Ocean water contains more salt than most continental lake water.
Oceans impact the weather over continents greatly
because they have a high specific heat which means they
store radiant energy and through convection transfer it
throughout the globe.
24. Which of the following traits is most influenced by the
environment?
F. Body weight
G. Eye color
H. Blood type
J. Color blindness
Environment doesn’t just mean trees, animals, and the Sun.
It also refers to influences that are not genetic in nature,
such as food intake, amount of exercise, etc.
25. How many elements are in the compound Mg(OH)2?
A.
B.
C.
D.
2
3
4
5
All element symbols start with a capital letter. The elements
in this compound are magnesium, oxygen, and hydrogen.
26. According to the periodic table, all of the following are metals
except —
F. sodium
G. zinc
H. fluorine
J. calcium
All elements found on the left of the staircase (metalloids)
are metals, except for hydrogen. All the elements found to
the right of the staircase are nonmetals.
27. Three students use their bodies to show how the sun, the moon,
and Earth are aligned during the phases of the moon. What is one
limitation of this model?
A.
B.
C.
D.
It cannot show the relative motion of the three objects.
It cannot be safely used to show gaseous objects such as the sun.
It cannot show how the sun’s light affects the moon’s appearance.
It cannot be used to show the direction of Earth’s revolution.
A limitation is a weakness of the model or something the
model cannot show.
28. A field geologist collected data for two nuggets of copper and
determined their density. Which two pieces of equipment did the
geologist most likely use to determine the density of the copper
nuggets?
F. balance and graduated cylinder
G. metric ruler and beaker
H. thermometer and Erlyenmeyer flask
J. specimen bottle and tweezers
• balance measures mass
• graduated cylinder measures precise liquid volume
• metric ruler measures small distances/lengths
• thermometer measures temperature
• Erlynmeyer flask is used to heat and store chemicals
• specimen bottle is used to hold objects for observation
• tweezers are used to pick up small objects
29. The petals of flowers often are brightly colored. These petals
provide a benefit for the plant because they —
A. prevent insects from taking pollen to other flowers
B. hide the plant from predators that would eat its flowers
C. protect the leaves from injury by birds and insects
D. attract insects that can carry the pollen needed for plant reproduction
Brightly colored flowers attract insects and birds to the
plant. The animal picks up pollen on itself. When the animal
flies to another flower, it can spread the pollen. Pollen is
used in reproduction of many plants.
30. Which of the following examples is a chemical reaction?
F. a pot of water boiling
G. an iron nail rusting
H. corn being ground
J. sugar dissolving in tea
Chemical reactions produce new substances different from
what you start and have indications of chemical changes (see
question 4.) Most chemical changes are not reversible.
31. The model of the atom above best represents which element?
A.
B.
C.
D.
Boron
Neon
Sodium
Carbon
Atoms are identified by their atomic number which is the
number of protons. Protons are positive (+).
32. Which of the following shows how the plant above would grow
if the pot were knocked on its side and left for several weeks?
• Geotropism-a plant’s roots will grow toward gravity and the
leaves will grow away from gravity
• Phototropism-a plant’s leaves will grow toward light
33. According to the periodic table, which of the following models best
represents a carbon atom?
A carbon atom has 6 protons, as indicated by its atomic
number.
34. Some data about the atmosphere of Mars are shown above. What
conclusion can be made about the ability of humans to breathe
Martian air?
F. Life support will be needed because
the percentage of oxygen is too low.
G. It will be impossible to breathe
because the percentage of nitrogen is too
low.
H. Oxygen and nitrogen will make it
possible for photosynthesis to produce
food.
J. Humans will be able to breathe the air
because oxygen is present.
Though Earth’s atmosphere is primarily nitrogen (78%),
about 20% is oxygen and essential for life. Humans expel
carbon dioxide as a waste product.
35. Which of the following is the most
reasonable topographic map of the area
shown in the picture?
The closer
together the lines
are, the steeper
the rise.
Element
Number of
Protons
T
7
Q
15
X
12
Z
17
36. The table above shows the number of protons in an atom of four
different elements. According to the periodic table, which of these
elements is a metal?
F. T
G. Q
H. X
J. Z
• The atomic number indicates the number of protons.
• Look up the elements on the periodic table.
• Elements to the left of the staircase are metals (except
Hydrogen)
37. Which energy transformation occurs when a match is lit?
A. Chemical energy to heat energy
B. Heat energy to potential energy
C. Electrical energy to heat energy
D. Kinetic energy to potential energy
• Chemical energy is a form of potential energy in foods and fuel. It is
released through chemical reactions such as digestion and combustion.
• Electrical energy is a form of energy that is present and flows through
electrical charge.
• Heat energy is a form of energy that is caused by the increase of speed
in molecules.
• Kinetic energy is a type of energy that occurs when a object is in
motion.
• Potential energy is a type of energy that is stored energy due to
position or mass.
38. As the air became polluted and darker, ______________ was
demonstrated in the darkening of the population of the peppered
moth in Europe over a relatively short period of time.
F. Natural selection
G. Natural integration
H. Kettlewell adaptation
J. Industrial modification
• Natural selection-Living things that have traits that are best-suited, or
adapted, to their environment survive and multiply
• Natural integration-no definition
• Kettlewell adaptation-no definition; Kettlewell did study the peppered
moth, though.
•Industrial modification-a company in Gardena, CA, specializing in
Refurbishment Of Material Handling Equipment
39. A tsunami can lead to massive devastation
on Earth, resulting in loss of life and property as
well as the destruction of the natural habitats
where it occurs. A tsunami is caused by
A.
B.
C.
D.
a tornado over the ocean
drilling for oil off the coast
an earthquake on the ocean floor
a strong hurricane developing over the ocean
• A tsunami is a giant wave.
• Tsunami can be caused by earthquakes on the ocean floor
or underwater landslides.
Football Player
Position
Mass (kg)
Velocity (m/s)
Half back
60
5
Tight end
90
5
Full back
110
5
Lineman
120
5
40. Which player would have the GREATEST kinetic energy?
F. lineman
G. half back
H. tight end
J. full back
•Kinetic energy is the energy of motion.
•The greater the speed, the greater the kinetic energy.
•The greater the mass, the greater the kinetic energy
41. Based on the food web above, what would happen if the wheat
plants were wiped out by a disease?
A. The field mice would thrive.
B. The flies would start eating flowers.
C. The field mice would start eating frogs.
D. The field mice would die off, and the wolf, hawk and snake
populations would suffer.
Organisms connected directly or indirectly to the ones that
are wiped out (or reduced) will be negatively affected. The
greater variety of organisms consumed reduces the effect.
42. Wetlands support a large number of animal species. Chemical
weed killers are dumped into this wetland and the aquatic plants are
killed. We should expect _______________ to be affected by the
death of the plants.
F. the insect and insect larva
G. the migratory bird populations
H. the animals that breed and nest here
J. all the animals in and near the wetlands
Organisms connected directly or indirectly to the ones that
are wiped out (or reduced) will be negatively affected. The
greater variety of organisms consumed reduces the effect.
43. At the county fair, Carrie and Sam climbed up on the carousel
horses. Around and around they went; the horses also bobbed up and
down. When they got off of the carousel, Carrie told Sam they had
been accelerating during their ride. Sam disagreed; they had been
moving at a constant speed. Who is correct and why?
A. Carrie is, because the carousel changed speed when it started and
stopped.
B. Sam is, because the horses never moved from their position on the
carousel.
C. Carrie is, because velocity includes speed and direction, and both
changed.
D. Sam is, they did not accelerate since their speed remained constant
for the ride.
Acceleration is a change in velocity. Velocity is speed and
direction of an object. Acceleration occurs when an object
speeds up, slows down, or changes direction.
44. It is theorized that Virginia’s Blue Ridge Mountains were pushed
up when tectonic plates converged. Which of the following best
depicts this process?
• continental plates sliding past each other are transform
boundaries and create faults and earthquakes
• a continental plate and ocean plate coming together form a
convergent boundary with subduction and can form volcanoes.
• continental plates that come toward each other form
convergent boundaries and form mountains.
45. Describe the structure of an atom.
A. The nucleus is the dense center of the atom composed of protons
and neutrons. Surrounding the nucleus is an electron cloud
composed of electrons.
B. The nucleus is the dense center of the atom composed of
electrons and neutrons. Surrounding the nucleus is an electron
cloud composed of protons.
C. The electron cloud is the dense center of the atom composed of
electrons. Surrounding the electron cloud is a nucleus composed of
protons and neutrons.
D. The electron cloud is the dense center of the atom composed of
protons and neutrons. Surrounding the electron cloud is a nucleus
composed of electrons.
46. Finch species living on the islands exhibit a variety of beak types
that favor different foods. Finches that eat seeds and plant parts
have beaks of the shorter, thicker variety while finches that eat
insects and other small organisms have thin, pointed beaks. Drought
has hit the Galapagos Islands. Plant species are dying out; seeds and
nuts have all but vanished. Of these four finch species, which is
MOST LIKELY to survive under these conditions?
F.
G.
H.
J.
Finch 1
Finch 2
Finch 3
Finch 4
47. Jenny accidentally drops her ring into a graduated cylinder. If the
ring has a mass of 5 grams and the water level in the cylinder rises
from 5 ml to 7 ml, determine the density of the ring.
•Density = mass/volume
• volume can be found using a graduated cylinder; the
amount of water displaced in the cylinder is equal to the
volume of the object. (subtract volumes)
D = m/v
D=?
m=5g
v = 2 mL (7 mL – 5 mL= 2mL)
D = 5g/2mL
D = 2.5 g/mL
2
5
48. What is an ADVANTAGE of sexual reproduction?
F. two parents are required
G. only one parent is required
H. it leads to genetically diverse offspring
J. It leads to genetically identical offspring
• Sexual reproduction-requires two parent organisms, but
will create a variety in the offspring.
• asexual reproduction-requires only one parent organism,
but all offspring are genetically the same including flaws in
the genes
49. If the forces acting upon an object are balanced, then an object
MUST
A. be moving
B. be accelerating
C. be sitting still
D. have a constant velocity
Newton’s 1st law of motion states that objects will remain at
a constant velocity (speed and direction) unless unbalanced
forces act upon the object. The 2nd law indicates that
unbalanced forces cause objects to accelerate.
50. Ridge X moves a total of 25 cm in 5 years. What is its rate of
movement expressed in cm/year?
F. 0.2 cm/year
G. 0.25 cm/year
H. 5 cm/year
J. 125 cm/year
Another word for speed is rate.
Speed = distance/time
S=?
d = 25 cm
t=5y
S = 25 cm/5y
Star
Light-years from Earth
Sun
2.0 x 10-6
Alpha Centauri
4.34
Sirius
8.80
Arcturus
35.86
51. According to the data table, Sirius is 8.80 light-years away from
Earth. That means –
F. Sirius is in our solar system.
G. Sirius is 8.80 times farther from Earth than the Sun.
H. It takes light from Sirius almost nine years to reach Earth.
J. It would take us almost nine years to reach Sirius by space shuttle.
A light-year measures how far light travels in one year. There
is only one star in our solar system and that is the Sun. We
currently have no technology that travels anywhere close to
the speed of light.
52. What is the number of protons in an atom of sodium?
The number of protons in
an atom is indicated by the
atomic number. The atomic
number is ALWAYS a whole
number.
Sodium’s atomic number is
11.
1 1
53. What is the name of the galaxy where Earth is located?
A.
B.
C.
D.
Andromeda Galaxy
Sun Galaxy
Comet Galaxy
Milky Way Galaxy
The name of our galaxy is the Milky Way galaxy.
54. You are sitting in a car that isn't moving; suddenly, the car quickly
accelerates. Your body seems to be pushed back against the seat.
Which word best explains why your body seemed to be pushed
backward against the seat?
F. newton
G. vector
H. inertia
J. gravity
The principle of inertia explains that an object has a
tendency to stay at the same velocity (either in the same
speed and direction or at rest.)
55. Large tides, called spring tides, are experienced in the Earth's
oceans when the sun is in position
A. Position A
B. Position B
C. Positions A & C
D. Positions B & D
Spring tides occur when the Sun, Earth and Moon are lined
up in a straight line. This is during the new and full moon
phases.