Download Storytown Grade 6 Lesson 26

CONTENTS
Draw and Evaluate Conclusions . . . . . . . . . . . . . . . . . . . .660
Draw conclusions about a text and evaluate the evidence
for the author’s conclusions.
Vocabulary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .662
Read, write, and learn the meanings of new words.
“Next Stop Neptune: Experiencing the
Solar System” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .664
by Alvin Jenkins • illustrated by Steve Jenkins
• Learn the characteristics of expository nonfiction.
• Summarize during and after reading.
“What Goes Up Doesn’t Always Come
Down” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .680
from NASA website
Read about space debris that orbits the Earth.
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .682
• Compare texts.
• Review vocabulary.
• Reread for fluency.
• Write a descriptive poem.
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Genr e: Ex
pos
Non
itor y
f ic t ion
Genr e: Websi t e
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Draw and Evaluate
Conclusions
A conclusion is a statement based on evidence. Information in
the text, what you already know about a topic, and what you
know from experience are kinds of evidence you can use to
support a conclusion. Drawing conclusions as you read can help
you figure out information the author does not tell you.
Authors of nonfiction often include their own conclusions
about a topic. You can evaluate an author’s conclusions by
asking these questions:
• Does the author give evidence to support the conclusion?
• Is the evidence reasonable?
Evidence
Evidence
Conclusion
A reasonable conclusion is
supported by evidence or facts. An
unreasonable conclusion is not.
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Read the paragraph below. The statement at the end of
it is the author’s conclusion. The graphic organizer shows
evidence that supports the conclusion. The evidence includes
information from the text and what the author already knows
about the topic.
All objects on Earth have weight. An
object’s weight is determined by its mass
and the force of Earth’s gravitational pull.
The farther an object travels from Earth, the
less weight it has. An object that weighs 1
pound on Earth weighs just 4 ounces when it
is 8,000 feet above Earth’s surface. An object
that continues to travel away from Earth will
eventually weigh nothing.
Evidence
The farther an object travels
from Earth, the less it weighs.
Evidence
I know that astronauts in space
float in a weightless environment.
Conclusion
An object that continues to travel away
from Earth will eventually weigh nothing.
Try This
The moon’s gravitational force is weaker than Earth’s. Would
an object weigh more or less on the moon than it does on
Earth? Find evidence in the text to support your conclusion.
www.harcourtschool.com/storytown
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Build Robust Vocabulary
Comet Crash!
mottled
barren
impact
scale
prominent
chasm
warped
distinctive
In 2005, NASA flew a space probe directly
into the path of the comet Tempel 1. The
scientists at NASA knew they would learn a
lot from the collision.
Before the mission, NASA scientists
knew only what the outside of the comet
looked like. They could see that its surface
was mottled, a look resulting from many
small craters. The surface seemed barren, but
scientists hoped to find out what was inside.
If the mission went smoothly, the impact
of the crash would release debris from the
comet’s interior for scientists to analyze.
Close-up photographs of the comet show its features at
the same scale as some close-up photographs of Earth.
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On July 4, the comet and
the probe hit each other at a
speed of 23,000 miles per hour.
The intense collision released a
prominent plume of debris. The
scientists did not immediately
see a gaping chasm where the
probe hit the surface. Instead, a
plume of dust warped their view.
It rose from a surface similar to a
snowbank.
This mission, which scientists
called Deep Impact, revealed
valuable information about what
makes up comets.
Different colors show which parts of the dust
plume were the brightest. Scientists studied
these distinctive patterns of light and color.
www.harcourtschool.com/storytown
Word Scribe
This week your task is to use the Vocabulary
Words in your writing. In your vocabulary journal,
write sentences to show the meanings of the
words. For example, you could write about something prominent
outside your school building or in your neighborhood. Write
sentences using as many of the Vocabulary Words as you can.
Share your writing with your classmates.
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NE X T
NEP
Exposi t o r y Non f ic t ion
Genre Study
Expositor y nonfiction presents and explains facts about
a topic. As you read, look for
• sections organized by
headings.
• captions with important
information.
K
W
L
What I
Know
What I
Want to
Know
What I
Learned
Comprehension
Strategy
Summarize the main ideas and
the most important details of
each section in a sentence or
two.
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S TOP
T UNE
E X PER IE NCI NG T HE SOL A R S Y S T E M
BY ALVIN JENKINS
ILLUSTR ATED BY
STEVE JENKINS
The solar system includes the sun,
Earth and seven other planets, more
than a hundred moons, thousands of
asteriods, and millions of comets.
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Neptune
CIRCL ING T HE SUN
The planets move in almost circular paths around the sun.
This illustration shows their paths, or orbits, but not their
actual spacing or size. Planets closer to the sun travel faster in
their orbits, while those farther away travel more slowly. The
outer planets also have much farther to go to circle the sun.
The time it takes to make a full orbit, or complete trip around
the sun, is called a year. A year on Mercury, the planet closest
to the sun, lasts about three Earth months. The planets also
rotate, or spin, as they travel around the sun. A day on a planet
is the length of time it takes the planet to rotate once.
V ER Y BIG, V ER Y EMP T Y
It’s hard to realize how big the solar system really is. And
because the planets are so small compared to the distances
between them, it’s hard to draw an accurate picture of the solar
system. Imagine the sun shrunk to the size of a basketball. At
this scale, the solar system is almost a mile and a half across,
and all of its planets and moons together could be held in the
palm of your hand. The solar system is mostly empty space.
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Sun
Earth
Mars
Saturn
Venus
Mercury
Jupiter
Uranus
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SUN
The sun is very bright and very, very hot. It is so hot that every
material we know of would become vapor—turn to gas—before
it could reach the sun’s surface. From a few million miles away,
you can see the sun rotate slowly. As you get closer, the surface
churns and roils, like water boiling in a pan. Sunspots—large
dark areas a few thousand miles across—move past below
you. A hundred thousand miles away, a spectacular column of
brilliantly glowing gas shoots into space and falls back to the
surface.
If you could dive into the sun, you’d find that there is
nothing solid—it’s made entirely of gas. Even so, the gas
at the center of the sun is so dense that a drinking glass
filled with it would weigh 75 pounds.
The sun is about 93 million miles from Earth. This distance is called
an astronomical unit, or AU. If there were a road to the sun, it would
take 177 years of nonstop driving at 60 miles per hour to get there.
The sun is rotating, but it is turning
faster at its equator than at its poles.
This is possible because the sun isn’t
solid—it’s made of gas. It takes 25
days for the sun to make one revolution
at the equator, 34 days near the poles.
The temperature at the sun’s surface
is 10,000 degrees Fahrenheit. At the
center of the sun, the temperature
reaches 28 million degrees.
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MERCURY
You are standing on a bare, lifeless planet. The ground is hard
and rocky and covered with gray dust. Everything is the same
dull color. There are mountains in the distance and rugged
terrain everywhere. There is no air, or atmosphere, on Mercury.
On all sides are craters made by the impact of meteorites and
asteroids. The sun, which has begun to set, looks much larger
than it does on earth. It is very hot. When the sun disappears
from sight it will quickly become very dark and extremely
cold—cold enough to freeze you almost instantly. But don’t
worry. It’s only 88 days until sunrise!
The surface of Mercury is
covered with craters formed
by the impact of comets
and asteroids, mostly in the
early years of the planet. An
asteroid one mile in diameter,
striking a rocky planet like
Mercury with a typical speed
of thirty miles per second
(over 100,000 miles per
hour), will blast a crater ten
to fifteen miles in diameter.
A day on Mercury lasts longer
than a year. Because it rotates
very slowly, sunrise to sunrise
here is 176 Earth days, but a
complete trip around the sun
takes only 88 days.
Mercury has the widest temperature range of any planet. It reaches
800 degrees Fahrenheit (hot enough to melt lead) by noon, and
falls as low as 280 degrees below zero just before dawn.
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VENUS
As you approach Venus, you see a smooth, unbroken white
cloud surface covering the entire planet. These clouds are
several miles thick and are not made of water, like the clouds
on Earth, but of tiny droplets of sulfuric acid. Below them there
is a thick layer of haze. Going lower, you finally emerge from the
haze into clear air about 20 miles above the surface of Venus.
When you finally stand on solid ground, you find yourself in
an extremely hot environment. It’s hotter here than inside a
fireplace with a roaring fire. The ground is covered with slabs
of rock, and barren mountains rise in the distance. Your vision
seems blurred and warped by the thick atmosphere. It’s very
overcast during the day, and a soft yellowish light seems to
come from everywhere. There are few shadows. Even at night
the clouds glow with a dim light, and you can’t see the sun or
stars. If you lived on Venus, you might never know of Earth,
or stars, or other planets, since they are always hidden by the
clouds. The high temperatures and lack of water mean that no
life, as we know it, can exist here.
Venus is closer to the sun than
Earth, so it always appears near
the sun in the sky and is visible
only in the morning or evening.
It is often called the Morning Star
or the Evening Star, but the second
planet from the sun is not a star,
because it doesn’t shine with its own
light, but by reflected sunlight. At its
brightest, Venus is brighter than all
objects in the sky except the sun and
the moon. Because of its beauty, this
planet was named after the Greek
goddess of love. In the past, many
people believed that Venus might be
covered with a giant ocean.
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EARTH
Approaching Earth from
space, your first impression
is of a beautiful blue ball
hanging in a black sky.
Getting closer, you see that
the blue is mottled with
white clouds and darker
areas of land. Bright white
regions of ice and snow
can be seen at the top and
bottom of Earth. Most of the
planet is covered with water.
The air is breathable, and in
most places on the surface the
temperature is comfortable—you
are home. This is the only place in the
solar system where you can survive without a
sealed spacesuit. Anywhere else it is too hot or too
cold, and either there is nothing to breathe or there’s an
atmosphere full of poisonous gases. Looking up from Earth
on a dark, clear night you can see six other planets without a
telescope: Mercury, Venus, Mars, Jupiter, Saturn, and Uranus.
The seasons on Earth are caused by changes in the angle of the sunlight striking the
surface. In the Southern Hemisphere the sun is directly overhead in the summer,
strongly warming the surface. In the winter the sunlight falls at more of an angle,
providing less warmth. The seasons are reversed in the Northern Hemisphere.
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M A RS
Here you are in a sandy, rocky landscape that looks a lot like a
desert on Earth. The air is thin and very cold. The wind whips
the fine red soil into fast-moving dust clouds. In the distance
a mountain rises above a steep cliff. The land nearby is gently
rolling, and has an orange color. The sky is yellowish because
of the dust in the air. Here and there are craters of various
sizes, and you can see what looks like a deep canyon. From
Mars, the sun looks smaller and fainter than on Earth. As it
sets, you can see two small moons in the sky above.
We have sent several probes
to Mars. Some of them, like
the Mars rover, have landed,
explored the surface, and sent
back pictures and information.
The temperatures on Mars are
low. The daytime temperature
on the Martian equator may be
as high as a cold winter day on
Earth, but for most of the planet
it is much colder, averaging
about 70 degrees below zero.
Valles Marineris is an enormous
chasm, 2,500 miles long and up to
6 miles deep. It is one of the most
prominent features on Mars.
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JUP I T ER
As you get close to this giant planet, you see that what at first
looked like the surface is really the tops of thick clouds. You
feel very heavy. In fact, you weigh two and a half times more
here than on Earth. Fast-moving, colorful bands of clouds
race past below you, encircling the entire planet. As you pass
through the layers of clouds—a white layer, an orange layer,
then a blue layer—the light fades and the temperature rises.
Occasionally a fl ash of lightning illuminates the clouds. The
atmosphere becomes thicker and thicker until, gradually, it
has become a liquid. This is not water, but an ocean of liquid
hydrogen. If you could keep going, you’d finally arrive at the
rocky core of Jupiter, where the pressure is enormous and it is
hotter than the surface of the sun.
Jupiter is big. It’s so big that
more than 1,300 Earths would
fit inside it. In fact, the fifth
planet contains more than
two-thirds of all the matter
in the solar system outside
of the sun. Seen from Earth,
this giant planet is usually the
fourth brightest object in the
sky, after the sun, the moon,
and Venus (sometimes Mars
is brighter than Jupiter).
Winds of up to 400 miles per hour blow across Jupiter.
These winds create the planet’s distinctive bands of
clouds. Among these bands is a huge red spot, nearly
three times the size of Earth. The Great Red Spot is a
fierce storm that has raged for more than 300 years.
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SAT URN
From far away, Saturn’s ring system is awesomely beautiful. As
you get closer the view becomes even more splendid. Saturn
shines as a bright yellowish ball, surrounded by colorful, fl at
rings that extend far from its surface. Passing through the
rings, you can see that they are made of millions of small rocks
and chunks of ice that range from the size of a pea to the size of
a house. There are so many pieces so close together that from
a distance they seem to form a solid sheet. Below the rings,
near the top of the clouds that cover Saturn, you enter a thick
layer of haze that dims your view of the cloud layers below.
Behind you the sun shines weakly. Here you weigh about the
same as on Earth, but the temperature is very low, colder than
anywhere on our planet. As you descend, you pass through
several layers of clouds, and the temperature and pressure
gradually increase. If you were to keep going, you’d reach a
rocky core deep within the planet. Here on Saturn the days pass
more quickly than on Earth—a full day is only about ten hours
long, about the same as on Jupiter.
Saturn, the sixth planet, is
twice as far away from the
sun as Jupiter. It is the second
largest planet, so large that
almost 800 Earths would fit
inside it. Saturn is a gas giant,
and it is much less dense than
Earth. In fact, Saturn would
float on water.
Saturn has three major rings
and many smaller ones. Though
the rings are many thousands
of miles across, they are only a
few hundred feet thick. This is
very thin—the same proportion
as a sheet of paper that is 100
yards across. The rings may be
the remains of a shattered moon
or other large object.
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UR A NUS
From space, Uranus looks like a blue-green sphere, with a few
dim points of light—its moons—and a faint set of rings closely
encircling the planet. As you pass near the rings, you can see
that they are made of chunks of rock and ice like the rings of
Saturn. Like the other gas giants, Uranus is completely covered
by clouds and has no visible solid surface. From here, the sun
looks like a very bright star. As you plunge into the clouds, you
pass through a blue-tinted layer of haze, then into clouds that
are banded like those on Jupiter. As on the other gas giants,
the temperature and pressure rise as you descend. If you could
keep going you would eventually reach a small rocky core, as in
Jupiter and Saturn.
Uranus
Earth
Uranus, the seventh planet, is
four times as large as Earth, and
almost twenty times as far from
the sun. You weigh about the
same here as you do on Earth.
At the cloud tops the temperature
is very low, about 330 degrees
below zero. The sun provides less
than 1 percent of the heat that it
does at Earth’s surface.
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NEP T UNE
Neptune, the eighth planet, is almost a twin of Uranus. The
clouds here look like those on Uranus, but have more of a
bluish tint. Neptune is slightly smaller than Uranus, but it is
denser. You weigh a little more here than on Earth. The sun
looks like a bright star, and it provides little light or heat. At
the cloud tops, the temperature is even colder than on Uranus.
Neptune’s moons look like faint points of light in the sky.
Entering the atmosphere you are blown sideways by winds
of up to 1,500 miles per hour, the fastest in the solar system.
There is a deep layer of clouds on Neptune, and once again
the temperature and pressure increase as you approach the
planet’s small, solid core.
At the cloud tops the
temperature here is
about 350 degrees
below zero.
It would take 5,100 years
to reach Neptune from
Earth if you were traveling
at 60 miles per hour.
A full cycle of day and
night on Neptune lasts
about 17 hours.
There are faint rings around Neptune.
Here and there the rings are brighter,
where more material has accumulated.
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T HINK CRI T ICA L LY
1 If you were standing on Mercury, how would the sun look
compared with the way it looks from Earth? MAKE COMPARISONS
2 The author says that it’s hard to imagine the size of the solar
system. Do you agree with his conclusion? Use text evidence
and what you already know to explain your answer.
DRAW AND
EVALUATE CONCLUSIONS
3 Do you think the author would support further space
exploration? Why or why not? AUTHOR’S PERSPECTIVE
4 If you could safely and quickly travel to any planet, which one
would you visit? Why? EXPRESS PERSONAL OPINIONS
5 WR ITE Write a note of caution to someone planning to visit
Neptune. In your note, describe what the visitor can expect on
the planet, and give suggestions for what to pack. SHORT RESPONSE
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A BOU T T HE AU T HOR
A LV IN JENKINS
Next Stop Neptune is the first book Alvin Jenkins worked
on with his son, Steve. However, the pair worked together
on numerous science projects when Steve was young. That
was about the time when the Space Age began and artificial
satellites first orbited Earth. Today Alvin Jenkins is a retired
professor of physics and astronomy. He lives in South
Carolina with his wife.
A BOU T T HE IL L US T R AT OR
S T E V E JENKINS
When Steve Jenkins was growing up, he loved to draw
insects and make animal scrapbooks. He planned to be a
scientist, but he was also interested in drawing and painting.
He says that working on science books for children allows
him to enjoy the best of both worlds. He is known for his
unique collage illustrations.
www.harcourtschool.com/storytown
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Science
http://What Goes Up Doesn’t Always Come Down
WHAT GOES UP
Websi t e
People have been launching objects into space for about 50
years. That adds up to a lot of stuff! Most of it has fallen back
to Earth. These objects have either landed or burned up in the
atmosphere. A few objects have been launched beyond Earth’s
gravity. These objects travel to other worlds or explore space.
But many of the objects that have been sent into space are
still in orbit. They are endlessly circling Earth.
This “junk” that is circling Earth is called orbital debris. On one
extreme, debris can be as small as tiny flecks of paint that have
come off spacecraft. On the other, large debris could
be satellites that are no longer working. The most common
source of orbital debris larger than 1 centimeter (cm), or 0.39 inch,
is the explosion of objects orbiting Earth. These are often rocket
upper stages. These can contain fuel or high pressure fluids.
To keep astronauts safe, scientists keep track of all the
debris in orbit. They sort pieces by their size. The diameter of the
piece is how scientists classify it. There are about 11,000 known
objects that are bigger than 10 centimeters. Scientists believe that
there are more than 100,000 pieces of orbital debris between 1 cm
and 10 cm. And there are tens of millions of pieces smaller than
1 cm! All pieces of debris larger than 10 cm are carefully tracked.
That information is used to estimate the number of small pieces of
debris. Even though this system cannot detect every piece, it can
give scientists an idea of the debris that is out there.
O RBITAL D EBRIS
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FROM NASA WEBSITE
T HE S PACE
In low Earth orbit, most “space junk” is moving super fast. It
can reach speeds of 4.3 to 5 miles per second. And if a spacecraft
is moving toward the debris, this speed can seem even faster!
The average impact speed of a piece of orbital debris running
into another object is 22,370 miles per hour (mph). Since it is
moving so quickly, a tiny piece of orbital debris can cause a lot
S HUTTLE
of damage. In fact, an 8.8-pound piece of debris could create the
same impact as a car moving at 60 mph!
Since we keep track of larger pieces of debris, crewed
spacecraft are able to dodge them. When an object is expected
to come within a few miles of the Space Shuttle, it changes its
path to avoid the object. The International Space Station can
also move away from debris in its path. Plus, the Station is also
the most heavily shielded spacecraft ever. It can survive impact
with smaller pieces of debris.
Since the smallest pieces of debris cannot be tracked,
collisions with them are bound to happen. The Space Shuttle
often returns to Earth with tiny impact craters. Impacts can
even create small cracks in the front
T HE I NTERNATIONAL
windows! Even though the spacecraft
S PACE S TATION
run into this debris quite often, the
debris rarely runs into other debris. In
fact, we know of only one time when
this actually happened!
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Comparing Texts
1. In “Next Stop Neptune,” you learned facts about the solar
system. How might you use those facts the next time you
are outside on a starry night?
2. What information in “Next Stop Neptune” and “What
Goes Up Doesn’t Always Come Down” might be useful
to someone who is training to become an astronaut?
3. Before you read “Next Stop Neptune,” what did you already
know about the solar system? How did reading the selection
change your ideas about the solar system?
Vocabulary Review
mottled
Word Sor t
barren
Sort the Vocabulary Words into categories. After you
finish, form a small group and compare the categories
that you chose to use. Explain why you categorized
each word as you did. Then choose two Vocabulary
Words from each category. Write a sentence for each
word. Share your sentences with the group.
impact
Noun
Adjective
Verb
Multiple-Meaning Word
scale
prominent
chasm
warped
distinctive
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Fluency Practice
Repeated Reading
You have learned that your reading rate
is the speed at which you can read a
passage correctly and still understand
what you read. With practice, you
can improve your reading rate.
Work with a partner. Reread aloud
the section about Jupiter on page
673 while your partner times your
reading with a stopwatch. Then
switch roles. Repeat this process
three times. Note how much you
increased your reading rate.
Writing
Write a Descriptive Poem
Choose one of the planets you learned
about in “Next Stop Neptune.” List the
planet’s characteristics and its unique
physical features. Then write a poem
about the planet. Your poem may be
rhymed or unrhymed.
My Writing Che
I
cklist
Organization
made a list of
characteristic
the planetÕs
s and its
al features.
unique physic
I selected the be
that describes
st information
the planet.
I organized my
ideas in a
es sense.
way that mak
Mars
1. rocky landscape
2. cold, thin air
3. dust clouds of red soil
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