Ohio Grade 8 Achievement Test for Science – May 2007
Annotated Item 24
Standard and Benchmark Assessed:
Standard:
Benchmark:
Earth and Space Sciences
D. Identify that the lithosphere contains rocks and minerals and that minerals
make up rocks. Describe how rocks and minerals are formed and/or classified.
Multiple Choice Question:
24.
What is the major process of surface rock formation on volcanoes?
A.
B.
C.
D.
Rock cools quickly from melted rock.
Rock is recrystallized by extreme pressure.
Rock solidifies slowly deep underground.
Rock is formed from deposited sediment.
Commentary:
This multiple choice question asks students to identify how surface rocks are formed on
volcanoes. Students must recall the processes by which different types of rocks are formed.
Students must understand that when magma reaches Earth’s surface as lava, it cools very
quickly because the air temperature is much cooler than the temperature in the volcano.
Students should recognize that since the lava cools so quickly, the igneous minerals that form
may not have time to crystallize at all (e.g., obsidian) or very small crystals are formed (e.g.,
pumice). Students may recall that the most common types of rocks found on the surface of
volcanoes are pumice, volcanic tuft, scoria and obsidian (volcanic glass). Answer choice A is
correct because quickly cooling melted rock is the major process by which volcanic rocks are
formed. Answer choice B is incorrect because rocks that form on the surface of a volcano are
not under extreme pressure and are not recrystallized. Answer choice C is incorrect because
slowly solidifying intrusive rocks are found deep in the Earth not on the surface of volcanoes.
Answer choice D is incorrect because sedimentary rocks are made from deposited sediments
that are lithified, which does not occur on the surface of volcanoes.
This question is classified as Recalling/Identifying Accurate Science because the task requires
students to recall the processes by which different types of rock are formed and to identify how
rocks are made on the surface of volcanoes.
Performance Data:
The percent of public school students selecting answer choice A for question 24 on the May
2007 Ohio Grade 8 Achievement Test for Science was 57%.
Keywords:
rock, volcano
Source: Ohio Department of Education
August 07