Download Grade 8 Science

Grade 8 Science Practice Test Text-to-Braille Answer Key
Question 1
Reporting Category: The Solar System & The Universe
Benchmark: SC.8.8.1 Compare the characteristics of the three main types of rocks
Answer Key: D
The table below shows how four different rocks were formed and gives their composition.
Granite is one kind of intrusive igneous rock.
Which rock described in the table is most likely granite?
A. 1
This answer is not correct. The characteristics of this rock are typical of sedimentary rocks.
Sedimentary rocks form from particles that are compressed (pushed) together over long
periods of time.
B. 2
This answer is not correct. The characteristics of this rock are typical of sedimentary rocks.
Some sedimentary rocks, such as limestone, form when the shells of marine organisms and
calcite are compressed (pushed) together over long periods of time.
C. 3
This answer is not correct. The characteristics of this rock are typical of some igneous rocks.
However, granite is an igneous rock that forms deep in Earth’s crust and not at the surface.
D. 4
This answer is correct. Granite is an igneous rock that forms when magma made of quartz
and other minerals cools and crystallizes below Earth’s surface.
Page 1 of 7
Grade 8 Science Practice Test Answer Key
Question 2
Reporting Category: The Solar System & The Universe
Benchmark: SC.8.8.10 Compare the characteristics and movement patterns of the planets in
our solar system
Answer Key: C
Which of the following best describes the inner planets of the solar system?
A. Large gas planets with thick atmospheres
This answer is not correct. This would be a good description for the outer planets, not the
inner planets.
B. Small planets of ice with elliptical orbits
This answer is not correct. All planets have elliptical orbits, but only the dwarf outer planets
are made up largely of ice.
C. Dense, rocky planets with few moons
This answer is correct. The four inner planets are known as the terrestrial planets because
they have solid surfaces and are made from dense minerals and rocks. The inner planets
have fewer moons compared to the outer planets.
D. Barren planets with rings of gas and dust
This answer is not correct. Some of the outer planets have rings of gas and dust, but none of
the inner planets have rings.
Page 2 of 7
Grade 8 Science Practice Test Answer Key
Question 3
Reporting Category: The Solar System & The Universe
Benchmark: SC.8.8.5 Explain the concepts of continental drift and plate tectonics
Answer Key: B
Which of the following best describes Earth’s tectonic plates?
A. They move away from each other at the equator.
This answer is not correct. Tectonic plate boundaries occur along Earth’s surface, not just at
the equator. At divergent plate boundaries, tectonic plates move away from each other.
B. They move because of convection currents in the mantle.
This answer is correct. Earth’s core and radioactivity within the mantle heat mantle
material. The heated material rises through the cooler material above it. This rising of
heated material and sinking of cooler material creates convection currents within the mantle.
This convection current in the mantle moves tectonic plates above it.
C. They collide at midocean ridges.
This answer is not correct. Midocean ridges are divergent plate boundaries. At divergent
plate boundaries, tectonic plates move away from each other.
D. They form at subduction zones.
This answer is not correct. The subduction zone is a region at a plate boundary where one
tectonic plate moves under another tectonic plate.
Page 3 of 7
Grade 8 Science Practice Test Answer Key
Question 4
Reporting Category: The Solar System & The Universe
Benchmark: SC.8.8.8 Describe the composition of objects in the galaxy
Answer Key: B
Many stars in the universe, including the sun, maintain fusion reactions in their cores. Such
stars are known as main sequence stars.
What is the primary fuel of main sequence stars?
A. Uranium
This answer is not correct. Heavy elements like uranium are created when a star goes into its
supernova stage. The supernova stage is after the main sequence stage in the stellar life
cycle.
B. Hydrogen
This answer is correct. A main sequence star, like the sun, is composed of about 73%
hydrogen and 25% helium. In their cores, main sequence stars fuse hydrogen to form helium.
Hydrogen is the fuel of a main sequence star.
C. Oxygen
This answer is not correct. Elements such as carbon, oxygen, and nitrogen make up only 2%
of the elements found in a main sequence star.
D. Carbon
This answer is not correct. Elements such as carbon, oxygen, and nitrogen make up only 2%
of the elements found in a main sequence star.
Page 4 of 7
Grade 8 Science Practice Test Answer Key
Question 5
Reporting Category: The Solar System & The Universe
Benchmark: SC.8.8.10 Compare the characteristics and movement patterns of the planets in
our solar system
Answer Key: C
The atmospheres of which two planets are composed mainly of hydrogen and helium gases?
A. Mars and Mercury
This answer is not correct. Mars’ atmosphere is mostly carbon dioxide. Mercury has a very
thin atmosphere composed of hydrogen, helium, and oxygen.
B. Mars and Saturn
This answer is not correct. Mars’ atmosphere is mostly carbon dioxide. Saturn’s atmosphere
is composed of mostly hydrogen and helium.
C. Saturn and Neptune
This answer is correct. Saturn and Neptune are both outer planets. Their atmospheres are
composed mostly of hydrogen and helium.
D. Venus and Neptune
This answer is not correct. Venus’ atmosphere is mostly carbon dioxide. Neptune’s
atmosphere is composed mostly of hydrogen and helium.
Page 5 of 7
Grade 8 Science Practice Test Answer Key
Question 6
Reporting Category: Biological & Physical Sciences
Benchmark: SC.8.6.1 Explain the relationship between the color of light and wavelength within
the electromagnetic spectrum
Answer Key: D
Which diagram correctly orders different colors of light according to the value of a property?
A.
This answer is not correct. The color of light is unrelated to its amplitude.
B.
This answer is not correct. The color of light is unrelated to its amplitude.
C.
This answer is not correct. Red light has a longer wavelength than blue light.
D.
This answer is correct. Red light has a longer wavelength than blue light.
Page 6 of 7
Grade 8 Science Practice Test Answer Key
Question 7
Reporting Category: The Solar System & The Universe
Benchmark: SC.8.8.2 Illustrate the rock cycle and explain how igneous, metamorphic, and
sedimentary rocks are formed
Answer Key: B
A rock is pushed deep underground in an area where mountain-building is occurring, and
undergoes the following processes.
•
•
•
First, the rock experiences high pressure that causes its minerals to align themselves in
bands.
Second, the rock is pushed further underground and completely melts, then erupts from
a volcano and hardens.
Third, the rock is broken down by wind and water into small particles, which flow into a
river and get compressed into rock.
Which order correctly shows this progression of rock types?
A.
This answer is not correct. The first stage is metamorphic and the second stage is
igneous.
B.
This answer is correct. The rock
formed from high pressure is metamorphic, the rock formed from the volcano is igneous,
and the last process causes it to be sedimentary.
C.
This answer is not correct. The second stage is igneous and the third stage is
sedimentary.
D.
This answer is not correct. The first stage is metamorphic and the third stage is
sedimentary.
Page 7 of 7