8th Grade Science -- 2005 Released Test

Venus, the moon, Mars, and the sun are all visible in our sky. All but one of these reflect light from another source. Which of the following produces its own light?
1. Venus
2. The moon
3. Mars
4. The sun
According to the graph, which air pollutant decreased the most from 1970 to 1991?
1. Carbon monoxide
2. Sulfur oxides
3. Particulates
4. Lead
Which of the following could best be used to demonstrate energy being transformed from electricity to heat?
1. A magnifying glass
2. A triple beam balance
3. A toaster
4. A gas oven
Which of these best describes a relationship shown by this African energy pyramid?
1. The lion is a predator of the giraffes.
2. The lion is the prey of the giraffes.
3. Giraffes are the prey of the trees.
4. Giraffes are predators of the lion.
Insulation materials reduce heat loss because they —
1. are poor conductors
2. block out the sun
3. reduce evaporation
4. promote convection
Which of the following classification groups contains organisms that have the most characteristics in common?
1. Kingdom
2. Phylum
3. Class
4. Species
In this diagram of a single-celled organism, which organelle functions as a place to store extra water?
1. Cell membrane
2. Vacuole
3. Cytoplasm
4. Nucleus
Which process is a physical change?
1. Rusting iron
2. Burning coal
3. Tarnishing silver
4. Melting ice
Which concept is best illustrated by this diagram?
1. The exchange of CO2 and O2 in an ecosystem
2. The effect of limiting factors in a biome
3. Cycling of nutrients in a community
4. Environmental pressures on a population
Water stored behind a dam is an example of what type of energy?
1. Kinetic
2. Potential
3. Solar
4. Chemical
What process makes food for plants?
1. Reproduction
2. Photosynthesis
3. Respiration
4. Condensation
In the diagram, what essential part of an electric circuit is missing at position X?
1. Load
2. On/off switch
3. Wires
4. Source of electric current
Which of the following has the least effect on lake water temperature?
1. The depth of the water
2. The angle of incoming sun rays
3. The number of fish in the lake
4. The lake’s surface area
Which of these experimental designs would best test this hypothesis?
Which animal has a life span closest to that of sheep?
1. Dog
2. Cat
3. Horse
4. Cow
When a base is mixed with an acidic solution, neutralization occurs because the —
1. base reaches absolute zero
2. acid evaporates
3. base chemically reacts with the acid
4. mass of the solution increases
Fossil fuels such as gas, oil, and coal have what kind of energy?
1. Mechanical energy
2. Chemical energy
3. Electrical energy
4. Nuclear energy
From the data given in this table, which characteristics help classify the seashells as belonging to the Tellin family?
1. Color, size, and hinge type
2. Color, size, and water temperature
3. Hinge type, location, and water temperature
4. Size, hinge type, and location
DNA is essential to living organisms because it —
1. carries the genetic code
2. is a spiral helix
3. can prevent diseases
4. can break apart
After fishing in the ocean, a student left his fishing gear in the sun to dry. Later, he noticed that small white crystals had formed on the rod, reel, and fishing line. Which of these is the best explanation of what occurred?
1. The water evaporated from the fishing gear, and sand was attracted to it.
2. The fish that were caught left scales on the fishing gear.
3. The salt in the ocean water reacted with the fishing gear and caused it to rust.
4. The water evaporated from the fishing gear, and salt from the ocean was left behind.
Which of these shows the correct sequence of development?
1. Organs → cells → tissues → systems
2. Cells → tissues → organs → systems
3. Systems → tissues → cells → organs
4. Tissues → cells → systems → organs
What type of energy does the windmill use to do work?
1. Mechanical
2. Nuclear
3. Chemical
4. Electrical
Which of these would be the best way to prove that a pine stick is more flexible than an oak stick?
Because zinc can combine with other substances but cannot be changed into a simpler substance by an ordinary chemical process, zinc is classified as —
1. a compound
2. a mixture
3. an element
4. an acid
Astronomers view objects in space through scientific instruments known as —
1. microscopes
2. hygrometers
3. telescopes
4. barometers
Which of the following is a true statement about the magnetic field between two magnets?
1. The south pole of one magnet is attracted to the south pole of the other magnet.
2. The south pole of one magnet is attracted to the north pole of the other magnet.
3. The north pole of one magnet is attracted to the north pole of the other magnet.
4. The south pole of one magnet is attracted to both poles of the other magnet.
What most likely happened to species that are found in the fossil record but have no living members?
1. They had offspring of a different species.
2. They mutated to other species.
3. They became extinct.
4. They never really existed.
According to the chart, on which planet would a ball fall the fastest?
1. Earth
2. Jupiter
3. Neptune
4. Saturn
In the chemical formula for ammonia, , what does the subscript 3 represent?
1. The number of nitrogen and hydrogen atoms in each molecule of ammonia
2. The number of hydrogen atoms in each molecule of ammonia
3. The number of ammonia molecules that will bond together
4. The number of nitrogen atoms in each molecule of ammonia
Which of these is a result of burning fossil fuels?
1. Acid rain
2. Clean water
3. Hydroelectric energy
4. Solar energy
Which of the following causes the Sun to appear to set?
1. The revolution of the Sun
2. The rotation of the Earth
3. The revolution of the Earth
4. The rotation of the Sun
An electric light bulb is hot to the touch because —
1. current passing through it produces heat
2. its magnetic field produces a large amount of heat
3. evaporation causes an object to heat up
4. its chemical reactions produce heat
In a food chain, the numbers of each type of population are usually in a relatively stable combination. A diagram of a food chain is shown above. If humans interfered by spraying an insecticide to kill the insects, what would be the next thing that would happen?
1. The number of hawks would increase.
2. The number of songbirds would decrease.
3. The number of grass plants would decrease.
4. The number of snakes would increase.
Which instrument would most accurately and precisely determine the mass of a toy car?
1. An electronic light meter
2. A spring scale
3. A triple-beam balance
4. A graduated cylinder
Organisms that absorb nutrients from dead plants and animals are called —
1. carnivores
2. decomposers
3. herbivores
4. producers
The diagram shows a block from the periodic table. The number six represents the —
1. atomic mass of the element carbon
2. atomic number of the element carbon
3. number of neutrons in the element carbon
4. number of valence electrons in the element carbon
Each student in a science class of 25 conducts the same experiment. One student gathers all the data from her classmates and summarizes the results of the experiment for the class. She compares the data she personally recorded with the class data. Which of these might indicate to her that her results are valid?
1. Three other classes performed the same experiment.
2. The same experiment was repeated two years in a row.
3. Many other students recorded data similar to hers.
4. Another student in her class reached a different conclusion.
Thrips are tiny insects that can easily be seen on roses. The thrip population changes shown in the graph above are probably caused by —
1. increases in human population
2. a major climatic change
3. seasonal changes
4. increased use of insecticides
A mixture of iron filings and sulfur can easily be separated by —
1. placing the mixture in water
2. performing a chemical reaction
3. heating the mixture
4. using a magnet
A student designs and builds a 1:1000 scale model of the Mt. Fuji volcano in Japan. Since Mt. Fuji is about 3,800 m high, what is the height of his scale model?
1. 0.38 m
2. 3.8 m
3. 380 m
4. 3,800 m
According to the data in the table, which sample of matter is most likely a metal?
1. 1
2. 2
3. 3
4. 4
When plants undergo photosynthesis, they produce —
1. carbon dioxide
2. oxygen
3. hydrogen
4. nitrogen
Expansion joints such as these are put on bridges because the concrete expands and contracts. This happens when —
1. chemicals get on the concrete
2. the temperature changes
3. the amount of light changes
4. the concrete gets wet
How far offshore is the deepest point of the ocean on this graph?
1. 0 m
2. 5000 m
3. 160 km
4. 240 km
A burning candle is in the process of transforming —
1. heat energy into chemical energy
2. chemical energy into light and heat
3. chemical energy into mechanical energy
4. chemical energy into nuclear energy
Mendel proposed that traits observed in pea plants resulted from a combination of “factors” inherited from each parent. His description of these “factors” can be considered the first scientific definition of the role of —
1. ribosomes
2. meiosis
3. genes
4. cell nuclei
Which of the organisms in a forest ecosystem is an example of a producer?
1. Squirrels
2. Oak trees
3. Black bears
4. Bacteria
Botanists often use leaves to identify plants. Which trait of the leaves shown would be most useful in identifying the plants they came from?
1. Color of the leaf
2. Function of the leaf
3. Arrangement of leaves on a stem
4. Presence or absence of veins
A tapeworm lives in human intestines, absorbing the nutrients that would normally be absorbed by the person. This eventually causes the person health problems. The relationship between the tapeworm and the human is —
1. parasite/host
2. predator/prey
3. herbivore/omnivore
4. consumer/producer
Of the states of matter, gas is the only state that —
1. is fluid
2. has mass
3. is highly compressible
4. has a definite shape