MS-ESS1-3NGSS*ScienceEarth and Space ScienceGrades 6-8
MS-ESS1-3: Analyzing Data to Find the Scale of Solar System Objects
In plain English: MS-ESS1-3 is the NGSS middle school performance expectation that asks students to analyze and interpret data to determine scale properties of objects in the solar system, such as the sizes of planets, layers, surface features and orbits. Students use data from telescopes and spacecraft, photographs with scale bars and scale models. It is usually taught in middle school Earth and space science.
Analyze and interpret data to determine scale properties of objects in the solar system.
Clarification Statement: Emphasis is on the analysis of data from Earth-based instruments, space-based telescopes, and spacecraft to determine similarities and differences among solar system objects. Examples of scale properties include the sizes of an object's layers (such as crust and atmosphere), surface features (such as volcanoes), and orbital radius. Examples of data include statistical information, drawings and photographs, and models.
Assessment Boundary: Assessment does not include recalling facts about properties of the planets and other solar system bodies.
Next Generation Science Standards · Disciplinary Core Idea: Earth's Place in the Universe · Official standard
Students analyze real data to find scale properties of solar system objects: how big things are compared with each other, such as a planet's width, the thickness of its layers, the height of a volcano or the size of an orbit. They work with data from Earth-based instruments (such as seismometers, which record earthquake waves, and telescopes), space telescopes and spacecraft. They read tables, compute ratios (how many times as large) and percents, measure photographs with a scale bar (a line on an image that shows a known length), summarize measurements with statistics, and build scale models. The goal is always a comparison backed by numbers, such as "Olympus Mons is about 2.5 times as tall as Mount Everest."
The NGSS Clarification Statement says: "Emphasis is on the analysis of data from Earth-based instruments, space-based telescopes, and spacecraft to determine similarities and differences among solar system objects. Examples of scale properties include the sizes of an object's layers (such as crust and atmosphere), surface features (such as volcanoes), and orbital radius. Examples of data include statistical information, drawings and photographs, and models." The Assessment Boundary says: "Assessment does not include recalling facts about properties of the planets and other solar system bodies." So every quiz and homework item on this page gives the data students need; nothing has to be memorized. Measurements are published values, rounded; images and data sets marked invented are made up for teaching.
Learning Objectives
By the end of this lesson, students will be able to:
Use ratios and percents from data tables to compare the sizes of solar system objects and their layers
Measure surface features and craters in images using a scale bar, and summarize the results with the mean, median and range
Compare orbital radii of moons in units of their planet's radius
Build and interpret scale models, and explain what each model shows and leaves out
Show a textbook-style poster of the planets lined up next to each other, all about the same size.
Warm-Up Prompt
"This poster shows Earth and Jupiter as about the same size. Jupiter is 142,984 km wide and Earth is 12,756 km wide. Is the poster a good model of their sizes? About how many Earths would fit side by side across Jupiter?"
Collect estimates. Then divide together: 142,984 ÷ 12,756 ≈ 11.2, so about 11 Earths fit across Jupiter. Point out that the answer came from data, not from the poster. Tell students that today they will use data the way scientists do, to find out how big things really are compared with each other.
Direct Instruction15 minutes
Key words. A ratio compares two sizes by dividing: Jupiter's diameter is 11.2 times Earth's. A diameter is the distance straight across a circle or sphere through its center, and the radius is half of it. The crust is a planet's rocky outer layer, the mantle is the thick layer of hot rock below it, and the core is the metal center. The atmosphere is the layer of gas around a planet. An orbital radius is the distance from the center of a planet (or star) to an object circling it. Use Diagram 2 with the first example and Diagram 1 with the last.
Layer sizes from seismometer data
Earthquake waves recorded by seismometers around the world show where Earth's layers begin and end. Earth's radius is 6,371 km. The crust under the continents averages about 35 km thick, the mantle is about 2,855 km thick, the outer core about 2,260 km and the inner core has a radius of about 1,221 km.
Result: Crust: 35 ÷ 6,371 ≈ 0.5% of the radius. Mantle ≈ 44.8%, outer core ≈ 35.5%, inner core ≈ 19.2%. On a globe 30 cm wide (radius 15 cm), the continental crust would be only 15 × 0.0055 ≈ 0.08 cm, less than 1 mm, about as thick as a fingernail.
A surface feature measured from orbit
A laser altimeter (an instrument that times laser pulses bounced off the ground) on the Mars Global Surveyor spacecraft measured Olympus Mons, a volcano on Mars, at about 22 km high and about 600 km across. Mount Everest is about 8.8 km above sea level. Mars's radius is 3,390 km.
Result: Olympus Mons is 22 ÷ 8.8 = 2.5 times as tall as Everest. Compared with its own planet it stands out even more: 22 ÷ 3,390 ≈ 0.65% of Mars's radius, while Everest is 8.8 ÷ 6,371 ≈ 0.14% of Earth's, about 4.7 times smaller as a fraction.
Orbital radius in planet radii
The Cassini spacecraft tracked Titan, Saturn's largest moon, orbiting about 1,221,870 km from Saturn's center. Saturn's radius is 58,232 km. Titan is 5,150 km wide, and Earth's Moon is 3,475 km wide.
Result: Orbital radius: 1,221,870 ÷ 58,232 ≈ 21 Saturn radii. Size: 5,150 ÷ 3,475 ≈ 1.5, so Titan is about one and a half times as wide as our Moon. Using the planet's radius as a unit makes orbits around different planets easy to compare.
Measuring a crater in a photograph
An image of Mercury's surface (invented for practice) has a scale bar: 2.5 cm on the image stands for 100 km. A crater on the image measures 3.4 cm across.
Result: Scale: 100 ÷ 2.5 = 40 km per cm. Crater: 3.4 × 40 = 136 km across. Always measure the scale bar on the same copy of the image, because enlarging or shrinking the copy changes both lengths.
Statistics: rocky planets and giant planets
Use the diameters in the table below. Find the mean (average) diameter of the four rocky planets (Mercury, Venus, Earth, Mars) and of the four giant planets (Jupiter, Saturn, Uranus, Neptune).
Result: Rocky planets: (4,879 + 12,104 + 12,756 + 6,792) ÷ 4 ≈ 9,133 km. Giant planets: (142,984 + 120,536 + 51,118 + 49,528) ÷ 4 ≈ 91,042 km. The giants are about 10 times as wide on average. Diagram 1 shows the same data as a scale drawing.
Planet diameters at the equator (published values, from telescope and spacecraft data)
Planet
Diameter (km)
Diameter (Earth = 1)
Mercury
4,879
0.38
Venus
12,104
0.95
Earth
12,756
1.00
Mars
6,792
0.53
Jupiter
142,984
11.21
Saturn
120,536
9.45
Uranus
51,118
4.01
Neptune
49,528
3.88
Ask: "Which planets are about Earth's size? Which are more than 3 times as wide?" Students should see two groups. Remind them that the page never asks them to memorize these values: the skill is reading the data and comparing.
Guided Practice15 minutes
Pairs analyze an invented image of a cratered region on the Moon. On the printout, the scale bar shows that 1 cm stands for 20 km. Pairs measured eight craters across the image.
Crater measurements from an image (invented data; scale bar 1 cm = 20 km)
Crater
Width on the image (cm)
A
0.6
B
1.1
C
0.8
D
2.4
E
0.5
F
1.4
G
0.9
H
5.2
Change every width on the image into a real diameter in km.
Find the mean, the median (the middle value when the values are in order) and the range (largest minus smallest).
One crater is much larger than the rest. Which measure, the mean or the median, better describes a typical crater here? Explain.
Write one scale statement that compares the largest crater with the smallest, such as "Crater __ is about __ times as wide as crater __."
Expected results: the diameters are 12, 22, 16, 48, 10, 28, 18 and 104 km. The mean is 258 ÷ 8 ≈ 32 km, the median is (18 + 22) ÷ 2 = 20 km and the range is 104 - 10 = 94 km. The median is the better typical value, because crater H pulls the mean up. Crater H is about 104 ÷ 10 ≈ 10 times as wide as crater E.
Independent Practice10-15 minutes
Data card analysis. Each pair gets one data card and writes a short report with (1) the scale statement the data support, with the calculation, (2) the instrument that collected the data, and (3) one drawing or model that would make the comparison clear to a fifth grader. Cards: Valles Marineris, a canyon on Mars, is about 4,000 km long and up to 7 km deep (spacecraft images and laser altimeter), while the Grand Canyon is about 446 km long and up to 1.8 km deep. Venus's clouds lie about 45-70 km above its surface (spacecraft and radar data), and Venus is 12,104 km wide. Ganymede, Jupiter's largest moon, is 5,268 km wide (Galileo spacecraft), and Earth's Moon is 3,475 km wide. Pairs share one finding with the class.
Closure5 minutes
Return to the warm-up poster and ask students to suggest one change that would make it a better model. Exit ticket: "Write one scale statement from today's data that surprised you. Include the numbers and the calculation." Look for a correct ratio or percent with units and a named data source.
Differentiation Strategies
For Struggling Students
Give the frame: "___ is about ___ times as ___ as ___, because ___ ÷ ___ ≈ ___."
Round large numbers first (142,984 to about 143,000) so the division is easier to check
Measure scale bars with a strip of paper marked in scale-bar lengths instead of a ruler
For Advanced Students
Ask students to find the percent of Earth's radius taken up by each atmosphere layer (troposphere about 12 km, stratosphere to about 50 km) and draw them to scale
Ask students how many Titans would fit side by side across Saturn (Saturn is 120,536 km wide and Titan 5,150 km), and to write the scale statement
Ask students to explain why a planet's volume grows much faster than its diameter, using a cube made of smaller cubes
Assessment Guidance
What to Look For
Check that ratios are set up in the right order (larger ÷ smaller for "times as large") and that the units match before dividing. Look for students who read a scale bar correctly and measure on the same copy of the image. Statements should name a comparison, a number and a data source. Students should not be asked to recall planet facts: if they need a value, it is on the card or in the question.
02
Classroom Activities
3 Activities
1
Paper Planets: A Size Scale Model
25 minGroups of 3-4
Groups build a model of planet sizes in which Earth is a paper circle 2.5 cm wide, then use it to compare sizes and to find what a size model leaves out.
Procedure
Use the diameter table: the model diameter is (Earth = 1 value) × 2.5 cm.
Draw each planet with a compass or by tracing round objects, and cut it out. Tape the giant planets to chart paper.
Line the planets up on the floor in order and photograph them next to a meter stick.
Safety: carry compasses point down and use blunt-tip scissors.
Expected Results
Model diameters: Mercury 0.96 cm, Venus 2.37 cm, Earth 2.5 cm, Mars 1.33 cm, Jupiter 28 cm, Saturn 23.6 cm, Uranus 10.0 cm, Neptune 9.7 cm. At this scale the Sun would be about 2.73 m wide, wider than a classroom door is tall.
Discussion Questions
Which two planets are almost twins in size? Which two?
The Sun at this scale is 2.73 m wide. What would you need to show it?
This model shows sizes. What does it leave out about the solar system?
Modification for Distance Learning
Students make the model with household objects whose sizes are close to the model diameters, measure them and post a labeled photo with a ruler in view.
2
Earth's Layers on a Paper Strip
20 minPairs
Pairs draw Earth's radius on a strip of adding-machine tape at 1 cm = 100 km, from the center to the surface, and then add the atmosphere and a satellite orbit to the same scale.
Procedure
Mark the center at one end. Use the layer data from Example 1: inner core to 12.2 cm, outer core to 34.8 cm, mantle to 63.4 cm, crust to 63.7 cm (the surface).
Color each layer. Label the depth of each boundary below the surface in km.
Above the surface, mark the layer that holds about 99% of the air (up to about 30 km) and the International Space Station's orbit (about 400 km up).
Discussion Questions
The crust is only 0.35 cm on the strip. How does its thickness compare with the whole strip?
Nearly all of Earth's air is in a layer only 0.3 cm thick at this scale. What does that tell you about the atmosphere?
Which data source told scientists where each layer ends, since no one has drilled through the crust?
Challenge Variation
Pairs make a second strip for Mars at the same scale, using these values: radius 3,390 km and core radius about 1,830 km (InSight seismometer data), and compare the two strips.
3
Volcano and Canyon Profiles from Spacecraft Data
20 minGroups of 3
Groups draw side views (profiles) of Olympus Mons and Mount Everest on graph paper at the same scale, using the spacecraft and survey data from Example 2, and explain what the drawing shows about surface features on Mars and Earth.
Procedure
Use 1 square = 10 km across and 1 square = 1 km up. Write this vertical stretch (10 times) on the drawing.
Draw Olympus Mons as a wide, gentle cone 600 km across and 22 km high. Draw Everest 8.8 km high on a base about 20 km wide (a simplified shape).
Below each, write the height as a percent of the planet's radius from Example 2.
Discussion Questions
Even with the stretch, Olympus Mons looks flat. What does that tell you about its shape?
Why did the class use a vertical stretch, and how could it mislead a reader?
The laser altimeter measured heights from orbit. Why is that better than estimating heights from shadows in a photo?
Modification for Distance Learning
Groups draw the profiles in a spreadsheet chart with the same axis settings and share the file.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Planet Sizes to Scale
A model built from the diameter table: every planet is drawn at the same scale, with Earth (shaded) 16 px wide. The four rocky planets on the left are small next to the four giant planets. The spacing between the planets is not to scale.
Diagram 2: Earth's Layers to Scale
Half of Earth drawn to scale from seismometer data: the inner core, outer core and mantle fill almost the whole radius. The crust (about 35 km under the continents) and the layer that holds nearly all of the air (about 30 km) are each thinner than the outline of the drawing.
04
Homework Assignment
~30 min
MS-ESS1-3 Homework: Reading the Scale of the Solar System from Data
Directions: Every problem gives the data you need. Values are published measurements, rounded; data marked invented are made up for practice. Show each calculation, and finish each problem with a scale statement such as "__ is about __ times as __ as __." Name the kind of instrument that collected the data when the problem says.
Part 1: Sizes, Layers and Surface Features (Problems 1-3)
You are making a poster 1 m wide, and the Sun (1,392,700 km wide) must fill the width. (a) Find the model diameters, in cm, of Jupiter (142,984 km), Earth (12,756 km), the Moon (3,475 km) and the dwarf planet Ceres (939 km). (b) Which objects would be too small to draw clearly? (c) Suggest a second poster that would show the small objects better.
Earth's atmosphere has layers: the troposphere, where weather happens, reaches about 12 km up; the stratosphere reaches about 50 km; the mesosphere reaches about 85 km. The International Space Station orbits about 400 km up. Earth is 12,756 km wide. (a) On a globe 30 cm wide, how high above the surface would each of these be, in mm? (b) Draw them to scale on a strip. (c) Write a scale statement about the layer where all weather happens.
In a photograph taken by the Cassini spacecraft, Saturn's moon Mimas (396 km wide) measures 8.0 cm across, and the large crater Herschel on it measures 2.8 cm across. (a) Find Herschel's real diameter. (b) What fraction of Mimas's width is the crater? (c) How wide would a crater with the same fraction of Earth's width (12,756 km) be?
Part 2: Orbits and Statistics (Problems 4-6)
Jupiter's radius is 71,492 km. Its four large moons orbit at these distances from Jupiter's center (spacecraft and telescope data): Io 421,700 km, Europa 671,100 km, Ganymede 1,070,400 km and Callisto 1,882,700 km. (a) Write each orbital radius in Jupiter radii, to one decimal place. (b) Make a scale drawing with Jupiter as a circle 1 cm in radius. (c) Describe the pattern in the spacing.
Radar from Earth-based dishes measured these diameters for a sample of 10 near-Earth asteroids (invented data), in meters: 120, 340, 85, 560, 210, 95, 1,300, 150, 260 and 180. (a) Find the mean, median and range. (b) Which value is an outlier, and how does it affect the mean? (c) Write one sentence that describes a typical asteroid in the sample.
A class wants one model on the school field that shows both the sizes of the Sun and Earth and the distance between them. Earth is 12,756 km wide, the Sun is 1,392,700 km wide, the Sun-Earth distance is about 149,600,000 km and Neptune orbits about 30 times as far out. (a) If Earth is 1 cm wide, how wide is the Sun, and how far away is it in meters? (b) How far away would Neptune be in km? (c) Explain why textbooks rarely show sizes and distances to the same scale.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Calculations
Ratios, scale factors, percents and statistics are correct, with units
Method is right but a value or unit is wrong
Scale Statements
Each problem ends with a clear statement comparing sizes or distances with numbers
Statement is vague ("much bigger") or has no numbers
Drawings and Models
Drawings use one stated scale and are labeled
Drawing mixes scales or has no labels
Interpretation
Explains what the data show and names the data source when asked
Restates the numbers without interpreting them
05
Quiz: 20 Questions
Interactive, with answers
Instructions
Every question gives the data you need, so you do not have to remember any planet facts. Values are published measurements, rounded; images and data marked invented are made up for practice. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
Mars is 6,792 km wide and Earth is 12,756 km wide. Which statement fits these data?
Answer: B
6,792 ÷ 12,756 ≈ 0.53, about one half. Choice A reverses the ratio. Choice C misplaces the decimal (0.053). Choice D ignores a difference of almost 6,000 km.
Question 2 of 20 · Multiple Choice
Data from the GRAIL spacecraft show that the Moon's crust is about 40 km thick on average, and the Moon's radius is 1,737 km. Earth's continental crust is about 35 km thick, and Earth's radius is 6,371 km. Which conclusion is supported?
Answer: C
Moon: 40 ÷ 1,737 ≈ 2.3% of its radius. Earth: 35 ÷ 6,371 ≈ 0.55%. The Moon's crust is about four times as large a fraction. Choice A reverses the comparison: Earth's crust is only about 0.55% of its radius, a smaller part than the Moon's 2.3%. Choice B ignores the very different radii. Choice D contradicts the data.
Question 3 of 20 · Multiple Choice
In a spacecraft image, a scale bar 1.6 cm long stands for 20 km. A crater on the same image is 4.8 cm across. How wide is the real crater?
Answer: D
The scale is 20 ÷ 1.6 = 12.5 km per cm, so the crater is 4.8 × 12.5 = 60 km across. Choice A multiplies 20 by 1.6. Choice B divides 20 by 4.8 (about 4.2). Choice C multiplies 20 by 4.8, as if 1 cm stood for 20 km.
Question 4 of 20 · Multiple Choice
The New Horizons spacecraft measured Pluto at 2,377 km wide. Earth's Moon is 3,475 km wide. Which statement fits these data?
Answer: A
2,377 ÷ 3,475 ≈ 0.68, about 2/3. Choice B reverses the ratio (3,475 ÷ 2,377 ≈ 1.46). Choice C ignores a difference of about 1,100 km. Choice D is off by a factor of about 7.
Question 5 of 20 · Multiple Choice
Mars orbits about 1.52 AU from the Sun, the dwarf planet Ceres about 2.77 AU and Jupiter about 5.20 AU (1 AU is Earth's average distance from the Sun). Where is Ceres's orbit?
Answer: B
From Mars to Jupiter is 5.20 - 1.52 = 3.68 AU. Ceres is 2.77 - 1.52 = 1.25 AU past Mars, and 1.25 ÷ 3.68 ≈ 0.34, about one third of the way. Choice A assumes it is in the middle. Choice C reverses the comparison. Choice D ignores that 2.77 is larger than 1.52.
Question 6 of 20 · Multiple Choice
Spacecraft landers measured the air pressure at the surface of Venus at about 92 times Earth's, and at the surface of Mars at about 0.006 times Earth's. Which conclusion do these data support?
Answer: D
92 ÷ 0.006 ≈ 15,000, so the pressure on Venus is thousands of times that on Mars: Venus has far more air above each square meter. Choice A reverses the data. Choice B ignores the huge difference. Choice C compares Venus with Earth, not with Mars.
Question 7 of 20 · Multiple Choice
Seven craters in an invented image have these diameters, in km: 14, 27, 8, 36, 21, 11 and 26. What is the median diameter?
Answer: A
In order: 8, 11, 14, 21, 26, 27, 36. The middle (fourth) value is 21 km. Choice B is the mean, 143 ÷ 7 ≈ 20.4, rounded. Choice C is the middle (fourth) value of the list as written, without sorting. Choice D is the fifth value in order, one place past the middle.
Question 8 of 20 · Multiple Choice
The InSight lander's seismometer showed that Mars's core has a radius of about 1,830 km. Mars's radius is 3,390 km. About what fraction of Mars's radius is its core?
Answer: C
1,830 ÷ 3,390 ≈ 0.54, a little more than one half. Choice A and Choice B are much too small. Choice D would leave almost no room for a mantle and crust.
Question 9 of 20 · Multiple Choice
In a scale model, Earth is a bead 1.5 cm wide. The Sun is 109 times as wide as Earth. How wide is the model Sun?
Answer: B
109 × 1.5 cm ≈ 164 cm, about 1.6 m. Choice A divides by 10 by mistake (16.4 cm). Choices C and D treat centimeters as meters (164 m) or move the decimal point (16 m).
Question 10 of 20 · Multiple Choice
Radar from the Magellan spacecraft measured Maxwell Montes, a mountain range on Venus, at about 11 km high. Mount Everest is about 8.8 km high. Which statement fits these data?
Answer: A
11 ÷ 8.8 = 1.25. Choice B uses the difference, 11 - 8.8 = 2.2 km, as if it were a ratio. Choice C reverses which is taller. Choice D ignores a difference of 2.2 km.
Question 11 of 20 · Multiple Choice
Neptune's moon Triton orbits 354,800 km from Neptune's center, and Neptune's radius is 24,764 km. Earth's Moon orbits 384,400 km from Earth's center, and Earth's radius is 6,371 km. Which statement fits the data?
Answer: B
In km, 354,800 is less than 384,400, so Triton is a little closer. In planet radii the difference is bigger: Triton is about 354,800 ÷ 24,764 ≈ 14 Neptune radii out, and the Moon about 384,400 ÷ 6,371 ≈ 60 Earth radii out. Choices A and C swap the two moons' values. Choice D cannot be right: an orbit half a planet radius from the center would lie inside the planet, and both moons orbit many planet radii out.
Question 12 of 20 · Multiple Choice
About 99% of Earth's air is in a layer about 30 km thick. Earth is 12,756 km wide. On a classroom globe 40 cm wide, about how thick would that layer be?
Answer: C
Scale: 40 cm ÷ 12,756 km. Air layer: 30 × 40 ÷ 12,756 ≈ 0.094 cm ≈ 0.9 mm, thinner than a coat of paint. Choices A, B and D move the decimal point or mix up cm and mm.
Question 13 of 20 · Multiple Choice
In 2017 the Juno spacecraft measured Jupiter's Great Red Spot, a giant storm, at about 16,000 km wide. Earth is 12,756 km wide. Which statement fits these data?
Answer: B
16,000 ÷ 12,756 ≈ 1.25, about 1.3 Earths across. Choice A moves the decimal point. Choice C flips the ratio in choice A (1/13 instead of 13), and choice D reverses the comparison (12,756 ÷ 16,000 ≈ 0.8): the storm is wider than Earth.
Question 14 of 20 · Multiple Choice
Spacecraft data give Jupiter's diameter as 142,984 km at the equator and 133,708 km from pole to pole. What does this show?
Answer: A
The difference is 142,984 - 133,708 = 9,276 km, and 9,276 ÷ 142,984 ≈ 6.5%, so Jupiter is flattened and bulges at its equator. Choice B ignores the difference. Choice C confuses the difference in km with a ratio. Choice D reverses which diameter is larger.
Question 15 of 20 · Short Answer
Use these spacecraft data: Ganymede is 5,268 km wide, Callisto 4,821 km, Io 3,643 km and Europa 3,122 km. Mercury, the smallest planet, is 4,879 km wide. Sort the five objects by size and write two scale statements about moons and planets.
In order: Ganymede (5,268), Mercury (4,879), Callisto (4,821), Io (3,643), Europa (3,122). Sample statements: "Ganymede, a moon, is about 1.08 times as wide as the planet Mercury (5,268 ÷ 4,879)." "Callisto is almost exactly Mercury's width (4,821 ÷ 4,879 ≈ 0.99)." "Europa is about 0.64 times Mercury's width." Being a moon or a planet depends on what an object orbits, not on its size.
Question 16 of 20 · Short Answer
Cassini data show that Saturn's main rings are about 270,000 km across but in most places only about 10 m thick. A sheet of paper is about 0.1 mm thick. If you built a model of the rings 27 cm across, how thick would they be? Compare that with a sheet of paper.
Scale: 27 cm stands for 270,000 km = 270,000,000 m, so the model is 1 billionth of real size. 10 m ÷ 1,000,000,000 = 0.00000001 m = 0.00001 mm. That is about 10,000 times thinner than a sheet of paper (0.1 ÷ 0.00001 = 10,000). A real paper model would be far too thick: the rings are extremely thin for their width.
Question 17 of 20 · Short Answer
The Voyager 1 spacecraft photographed a volcanic plume (a fountain of gas and dust) about 300 km high on Io, a moon 3,643 km wide. What percent of Io's radius is the plume's height? How high would a plume with the same percent of Earth's radius (6,371 km) be?
Io's radius is 3,643 ÷ 2 ≈ 1,822 km, so the plume is 300 ÷ 1,822 ≈ 0.165, or about 16%, of Io's radius. On Earth: 0.165 × 6,371 ≈ about 1,050 km high, more than twice as high as the International Space Station's orbit. Io's volcanoes are huge for the size of their moon.
Question 18 of 20 · Short Answer
Mars's radius is 3,390 km, its core radius is about 1,830 km (InSight seismometer data; you may use your answer to question 8) and its crust is estimated at about 24-72 km thick. Earth's radius is 6,371 km and its core radius is about 3,481 km. Use a strip model with 1 cm = 100 km to compare the two planets' layers.
Mars strip: 33.9 cm long, with the core to 18.3 cm and the crust as the last 0.24-0.72 cm. Earth strip: 63.7 cm long, with the core to 34.8 cm. Both cores fill a little more than half the radius (Mars 1,830 ÷ 3,390 ≈ 54%, Earth 3,481 ÷ 6,371 ≈ 55%), so the two planets have similar layer proportions, but Earth's whole strip is almost twice as long. Mars's crust may be a larger part of its radius (0.7-2.1%) than Earth's continental crust (about 0.5%).
Question 19 of 20 · Short Answer
The Kuiper Belt, a band of icy objects beyond Neptune, stretches from about 30 AU to about 50 AU from the Sun. Mars orbits at about 1.5 AU. In a model where 1 AU = 1 cm, where would the belt start and end, and how does its width compare with the distance from the Sun to Mars?
The belt would run from 30 cm to 50 cm from the model Sun, so it is 20 cm wide. The Sun-to-Mars distance is only 1.5 cm, so the belt is about 20 ÷ 1.5 ≈ 13 times as wide as the whole distance from the Sun out to Mars.
Question 20 of 20 · Short Answer
A student says, "Jupiter is about 11 times as wide as Earth, so about 11 Earths would fit inside it." Use the data (Jupiter 142,984 km wide, Earth 12,756 km wide) to evaluate this claim.
The first part is right: 142,984 ÷ 12,756 ≈ 11.2, so about 11 Earths fit across Jupiter. The second part is wrong, because volume grows in three directions at once: 11.2 × 11.2 × 11.2 ≈ 1,400, so roughly 1,300-1,400 Earths would fit inside Jupiter (the real value is about 1,321, because Jupiter is slightly flattened). Comparing widths and comparing volumes give very different scale statements.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-ESS1-3 mean?
MS-ESS1-3 asks middle school students to analyze and interpret data to figure out how big solar system objects and their parts are compared with each other. The code stands for Middle School, Earth and Space Science, core idea 1 (Earth's Place in the Universe), performance expectation 3. The practice is data analysis: students compute ratios, read images with scale bars and build scale models from data.
What are scale properties in MS-ESS1-3?
Scale properties are sizes and distances compared with each other. The Clarification Statement gives the sizes of an object's layers (such as crust and atmosphere), surface features (such as volcanoes) and orbital radius as examples. A scale statement says how many times as large one thing is as another, such as "Jupiter is about 11 times as wide as Earth."
Do students have to memorize planet facts for MS-ESS1-3?
No. The Assessment Boundary says assessment does not include recalling facts about properties of the planets and other solar system bodies. Tests should give students the data, and students should show that they can analyze it. On this page every quiz and homework item includes the numbers needed.
Where does the data for MS-ESS1-3 come from?
From Earth-based instruments, space telescopes and spacecraft, as the Clarification Statement says. Examples: seismometers on Earth (Earth's layers), Earth-based radar (asteroid sizes), space telescopes such as Hubble (distant objects), and spacecraft such as Cassini, Juno, New Horizons and Mars orbiters and landers (moons, storms, volcanoes and planet interiors).
How do you measure a crater from a photo with a scale bar?
Measure the scale bar and the crater on the same image with a ruler, then use the scale. If 2 cm on the image stands for 50 km, each centimeter is 25 km, so a crater 3 cm across is 75 km wide. Enlarging or shrinking the image is fine, as long as you measure the scale bar on that same copy.
What statistics do students use in MS-ESS1-3?
Mostly ratios, percents, the mean, the median and the range. For example, students can compare the mean diameter of the rocky planets with that of the giant planets, or summarize crater sizes from an image with the median. They should also notice outliers, which pull the mean away from a typical value.
Why can't one model show both planet sizes and distances?
Because the distances are enormous compared with the sizes. If Earth were 2 cm wide, the Sun would be about 2.2 m wide but about 235 m away, and Neptune would be about 7 km away. A model that fits on a page or a field must choose: show sizes, or show distances.
What mistakes do students make with scale data?
Frequent mistakes include dividing in the wrong order, mixing units (km with m, or cm with mm), reading a scale bar from a different copy of an image, and saying "11 times as wide" means "11 times as big inside." Asking for a scale statement with the calculation written out catches most of these.
How does MS-ESS1-3 connect to math?
It uses grade 6 and 7 math in a science setting: ratios and rates (6.RP.A.3), statistics such as the mean and median (6.SP.B.5) and scale drawings (7.G.A.1). Students also work with very large numbers and metric unit conversions.
What comes after MS-ESS1-3?
In middle school it pairs with MS-ESS1-1 (the Earth-sun-moon system) and MS-ESS1-2 (gravity in the solar system and galaxy). In high school, HS-ESS1-6 uses evidence from meteorites and other planetary surfaces to reconstruct Earth's early history, and HS-ESS1-4 predicts orbits with math, both beyond this standard.
07
Related Standards
5 standards
These standards connect to MS-ESS1-3: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
6.RP.A.3Prerequisite
Use ratio and rate reasoning to solve real-world problems
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