The following data for the Sun and the four inner planets of the Solar System have been observed.
Mean Distance
from the Sun
(million
kilometers)
Sun
Diameter
(kilometers)
1,400,000
Mercury
58
4,900
Venus
108
12,100
Earth
150
12,800
Mars
228
6,800
In a simplified model of the Solar System, the planets revolve around the Sun in circular orbits, all in
the same plane. Each planet has a different period of revolution. Also, each planet is a sphere that
rotates about an axis through its center, but with a different period of rotation. In this model the axis
of rotation of each planet is perpendicular to the plane of the orbit.
NAEP released item, grade 12
1. The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
NAEP released item, grade 12
Scoring Guide
Score & Description
Complete
Student demonstrates an understanding of both speed of an object and the geometry of a circle by
describing how to calculate the speed of a planet of known orbital radius and period of revolution.
Student response recognizes that speed is distance divided by time, and that in one complete
revolution the distance is 2 times the radius of the orbit and time is the period of revolution. The
response does not have to provide a numerical calculation.
d 2 r
2 (150 x 106 km)
6
v = — = ——— = ———————— = 2.6 x 10 km/day
t
t
365 days
Essential
Student response recognizes that the speed is the circumference of the orbit divided by the period
of revolution, but does not indicate how to determine the circumference.
Partial
Student response recognizes only that a speed is distance divided by a time (v = d/t), or
equivalently that distance equals speed multiplied by time (d = vt), but indicates neither a correct
distance nor time. Response may falsely interpret the radius of the orbit as the distance, or the
period of rotation as the period of revolution.
Unsatisfactory/Incorrect
Student response does not recognize that the estimate involves dividing distance by a time.
Complete - Student Response
1 The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
NAEP released item, grade 12
Scorer Comments:
Student response states that speed is calculated by dividing distance by time, while recognizing
that the distance is represented by the circumference of the orbit, 2 r, and the time - by the length
of time it takes to complete one revolution, 365 days.
1 The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
NAEP released item, grade 12
Scorer Comments:
Student response consists of a calculation showing that the distance is the circumference of the
orbit, 2 r, and the speed v is the distance divided by the length of time it takes to complete one
revolution, 365 days.
Essential - Student Response
1 The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
Scorer Comments:
Student response states that speed is calculated by dividing distance by time, while recognizing
that the distance is represented by the circumference of the orbit, and the time - by the length of
time it takes to complete one revolution, 365 days. The response neglects to specify how the
circumference can be calculated using the data table (d=2 r).
1 The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
NAEP released item, grade 12
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
Scorer Comments:
Student response states that speed is calculated by dividing distance by time, while recognizing
that the distance is represented by the circumference of the orbit, and the time - by the length of
time it takes to complete one revolution. The response neglects to specify how the circumference
can be calculated using the data table (d=2 r).
Partial - Student Response
1 The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
NAEP released item, grade 12
Scorer Comments:
Student response states that speed is calculated by dividing distance by time, correctly identifies
365 days as the time, but uses the radius of Earth's orbit for the distance instead of its
circumference.
1 The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
Scorer Comments:
Student response states that speed is calculated by dividing distance (# of km) by the time it takes
NAEP released item, grade 12
to complete one revolution, but does not specify that the distance is represented by the
circumference of the orbit or how the distance can be calculated using the data table.
1
Unsatisfactory/Incorrect - Student Response
The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
kilometers per day as it moves in its orbit around the Sun.
Scorer Comments:
Student response mentions time and distance, but shows lack of understanding of what the time
relates to, and how the variables are related.
1
The table below gives additional information about the planets: their periods of revolution about the
Sun and rotation about their axes.
Planet
Mean Distance
from the Sun
(million kilometers)
Period of
Revolution
(Earth time)
Period of
Rotation
(Earth time)
Mercury
58
88 days
59 days
Venus
108
225 days
243 days
Earth
150
365 days
23.9 hours
Mars
228
687 days
24.6 hours
Describe how you could best determine, from the data given on page 6, the speed of the Earth in
NAEP released item, grade 12
kilometers per day as it moves in its orbit around the Sun.
Scorer Comments:
Student response mentions time and distance, but shows lack of understanding of what the
distance relates to, and how the variables are related.
NAEP released item, grade 12
2000 National Performance Results
Score
Percentage of Students
Unsatisfactory/incorrect
Partial
49%
13%
Essential
5%
Complete
4%
Omitted
Off task
22%
7%
Note:
•
•
These results are for public and nonpublic school students.
Percentages may not add to 100 due to rounding.
The Fields of Science: Earth & Space Sciences (Sub content classification: Earth in Space)
Knowing and Doing Science : Practical Reasoning
NAEP released item, grade 12
The Fields of Science
Earth & Space Sciences
This question measures basic knowledge and understanding of the following:
Earth in Space
•
•
•
•
•
•
•
setting of the Earth in the solar system;
setting and evolution of the solar system in the universe (not in grade 4);
tools and technology that are used to gather information about space;
apparent daily motions of the Sun, the Moon, the planets, and the stars;
rotation of the Earth about its axis, and the Earth's revolution around the Sun;
tilt of the Earth's axis that produces seasonal variations in climate; and
earth as a unique member of the solar system that may be approximated in other galaxies in
the universe, and that evolved at least 4.5 billion years ago.
Knowing and Doing Science
Practical Reasoning
Practical reasoning probes students' abilities to use and apply science understanding in new, realworld applications.
NAEP released item, grade 12