Curriculum: Standards - Cengage Learning

PATHFINDER EDITION JANUARY-FEBRUARY 2011 TEACHER’S GUIDE ngpathfinder.org

pathfinder edition nGpathfinder.orG January-february 2011 Dear Educator:

ARCTIC ALERT!8 Losing your head might seem like a big deal, but it depends on who you are. Some animals can
Second Chances 2 Space Quest 16 lose a leg, arm, tail, or head, and survive. We explore the process of regeneration in this month’s
opening story, “Second Chances.”

In “On Thin Ice,” students will go “still hunting” with polar bears to learn about the challenges these
animals face in a warming world. Global climate change is altering the bears’ habitats, making
survival difficult.

In our final story, “Space Quest,” you and your students will blast off with a NASA astronaut as
he journeys into space in the space shuttle Columbia. Don Thomas has a great view of Earth,
the planets in our solar system, the sun, and plenty of other stars from the shuttle window. After
reading the issue, use the Comprehension Check on page T22 to help your students review their
understanding of the stories.

I hope you enjoy this month’s issue. As always, if you need to reach me, feel free to email me at
[email protected]. I appreciate hearing from you.

Let the exploring begin!

Editor, EXPLORER MAGAZINE

Second Chances, pp. 2-7 On Thin Ice, pp. 8-15 Space Quest, pp. 16-23

Curriculum: Standards Curriculum: Standards Curriculum: Standards

• Life Science: Cells are fundamental organizing • Life Science: How animals in an ecosystem • Space Science: Understand the organization
principals of life; cells have structures and interact; habitats and niches; influence of of the solar system and the relationships among
perform specific functions; life cycle of human activity on ecosystems the various bodies that comprise it; rotation of
organisms Earth around the sun
• Earth Science: Earth patterns; cycles and
• Language Arts: Ask questions to self monitor change • Language Arts: Access and use prior
reading; set purpose for reading; use context knowledge; set purpose for reading;
clues to determine meanings of unfamiliar • Language Arts: Skim text to develop a identify new information in text; check for
words; develop academic vocabulary general overview of content; use information understanding; categorize information; develop
from text to make inferences; identify cause- academic vocabulary; research
and-effect relationships; develop academic
vocabulary; informational writing; research

T1

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Before Reading

Preview and Set a Purpose Explain that setting a purpose, or reason,
for reading can help readers find information. Read the title of the story,
“Second Chances.” Ask: What questions come to mind when you read
the title? Write them on your paper. Next, have students flip through the
story and look at the images and captions. Invite them to write three
questions they hope the story will answer. Explain that they are going to
read the story to find the answers.
LIFE ScIEncEComprehension Strategy: As you read thisby Lana Costantini
story, check in with yourself. Ask: “Does
Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.this make sense?” If not, try rereading,Some animals can lose a leg, arm, tail,
reading more slowly, or reading the or head, and survive.

next part. They simply grow back the lost part.

23 Comprehension Strategy

Second Chances Ask Questions Say: “When you are confused about something, you can
ask questions.” Remind students they should ask and answer questions
About the Story as they read, too. This strategy helps readers stay focused on the text.
Display the following tips:
In “Second Chances,” readers will learn about
animals that can lose critical body parts—legs, • As you read, think about what you need to understand better.
internal organs, even heads—and still survive. How? • Think about the text. Ask questions using the 5 Ws: Who, What, When, Where,
They have the ability to regenerate lost or damaged
body parts. Salamanders and sea cucumbers are just and Why.
two of the regeneration champs students will read • Reread the text or read on to find the answers.
about. Along the way, they’ll discover the important
role cells play in this amazing process. Readers will Comprehension strategy name:
also learn that scientists are eagerly studying these
cells to learn how the cells regenerate body parts. Read aloud the “Smart Parts” section on Q&A
They want to use what they learn to help humans page 4 of the story. Provide students with
regrow body parts. the language frames below. Model asking As you read the “Second Chances” story, stop at the end of each section. What questions
questions. For example: come to mind? Record your questions and the answers you find in the story below.

• I need to understand what regeneration means. Page Question Answer
• I ask myself, ‘What does regeneration mean?’
• I read and find that it is the ability to regrow an

injured or lost body part.

Distribute the activity on page T14 before How did you figure out the answers to your questions? Tell a partner.
reading the story. Encourage students to _____________________________________________________________________________________
record their questions and answers as _____________________________________________________________________________________
they read. _____________________________________________________________________________________

_____________________________________________________________________________________

T14 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011

T2

PATHFINDER EDITION JANUARY-FEBRUARY 2011

The great warrior Hercules stood in a A sea star regrows Extreme Makeover Just Dropping Off Academic Vocabulary
part of its arm.
murky swamp with his bow drawn. He Salamanders aren’t the only animals that can Some animals lose body parts accidentally. Context Clues Display the Academic Vocabulary words: autonomy,
steadied himself and shot flaming arrows replace body parts. Many lizards can replace Others do it on purpose. This defense is cell, invertebrates, regeneration. Using self-stick notes, have students
toward the den of Hydra. Hydra was a terrible their tails. If a sea star loses one or more called autonomy. find each vocabulary word in bold and mark its place. Explain that when
beast. She had nine heads and the body of arms, new ones sprout. If a predator bites off you read, you may come to a word you don’t know. But don’t worry!
a snake. Hercules had been sent to kill her, a salmon’s fin, another grows. Then there’s the When faced with a threat, an octopus can Sometimes you can figure out a word’s meaning by looking at other
but she was hiding in her den. Suddenly, she flatworm. It can regrow its whole body—even break off a wriggly arm. A crab can lose a words and phrases near the word. Remind students to look for signal
sprang out. Then she wrapped one of her coils its head! claw. The crab takes this defense even further. words and phrases such as is, means, like, or unlike to help find the
around Hercules, trapping him. Before shedding a claw, it can lock the claw on context clues. Also note that sometimes the definition is in the sentence.
All these animals can regrow body parts. Yet a predator in the “pinch” position. Ouch! Other times the definition is in the sentence before or after the word is
Hercules raised his mighty sword and dealt some are better at it than others. Invertebrates introduced.
a fierce blow to Hydra, cutting off one of her are makeover champs. An invertebrate is an A sea cucumber’s defense is even more
heads. It was then that Hercules discovered animal without a backbone. extreme. It ejects its internal organs when Have partners use context clues to figure out the meanings of the
one of Hydra’s terrifying powers. For every a predator threatens it. A cloud of toxic boldface terms. Then have students skim the story and find other
head he cut off, Hydra grew two more in Look at the squishy sea squirt. This boneless, guts shoots from the sea cucumber, hitting unfamiliar words. Invite volunteers to share their words, context clues,
its place. After a terrible battle, he finally potato-shaped sea creature spends its life stuck its attacker. Without internal organs, most and definitions.
defeated her. to undersea rocks. Here’s the cool part. A sea animals would quickly die. But the sea
squirt can regrow its entire body from a single cucumber immediately starts to grow a new Finally, have students add these words to their Academic Vocabulary
blood vessel. set of organs to replace the old ones. Logs or to your classroom word wall.

Smart Parts Repair Kit Colorful sea squirts can Fast Facts
regenerate their entire bodies
The story of Hercules is an ancient myth. Hydra Let’s look at regeneration in action. A small from just one blood vessel. • Regeneration can be a response to an injury, part of an animal’s defense,
was not a real creature. Yet it is said that this salamander looks out from a pile of leaves. Is it or part of a seasonal event.
myth is based on something real. In the story, safe to leave its hiding place to search for food?
Hydra grew back her missing heads. Believe it It creeps out. Wham! A garter snake strikes. • Spiders can regrow missing legs or parts of legs.
or not, some animals can regrow some of their It grabs the salamander’s leg. The salamander • A person can regrow his or her liver after losing as much as 75 percent of
body parts. wriggles. It struggles. It gets away! Well, most
of it escapes. Its leg still dangles from the the organ.
This process is called regeneration. That is snake’s mouth.
the ability to repair or regrow injured or lost Comprehension Quick Check
body parts. For many animals, losing a leg could
mean disaster. It’s harder to hunt or run from Explain regeneration and give two examples from the story.
Does this sound like science fiction? It’s not. predators. Not for the salamander, though. A (Regeneration is the ability to repair or regrow injured or lost
Animals that can regenerate can repair wounds new leg starts to grow within 12 hours. Skin, body parts. Numerous examples are named in the story.)
that might threaten their lives. They can use muscle, bone, and nerves form. A month later,
regeneration to trick, or even fight, predators. the amphibian has a fourth leg again. It can
Some use it to help find a mate. For all of these regrow its tail, jaw, intestines, and eyes, too.
animals, regeneration is about survival.

A salamander regrows
the tip of its tail.

4 NatioNal GeoGraphic explorer 5JaNuary-February 2011

Explore Science

Say: We learn in the story that regeneration is the
ability to repair or regrow injured or lost body parts. In
what ways is this useful to animals? (Answer: repair
wounds, trick or fight with prey, stay alive)

Display these words: salamander, sea star, sea squirt,
lizard, crab, and sea cucumber. In pairs, have students
scan pages 4 and 5 to find out what body parts these
amazing animals are able to regenerate. Have students
jot down answers, then record responses below each
animal’s name. (Answers: salamander – legs, tails,
jaws, intestines, eyes; sea star – arm; sea squirt –
entire body; crab – claw; lizard – tail; sea cucumber –
internal organs)

Ask: How do you think these animals lose their different
body parts? What does the story tell you? What other
possible reasons can you think of? (Answers will vary.)

T3

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Bigger, Better Life’s Building Blocks Going Back in Time Engage Students

Some animals grow new body parts only after It’s easy to see why being able to grow new When scientists took a close Watch It Happen Have students watch a video about regeneration
an emergency. Others do it every year. It’s part body parts can help animals. Figuring out how look at injured salamanders, and salamanders. After viewing, ask students if there was anything that
of their natural growth cycle. they do it puzzled scientists for a long time. they found something surprising. surprised them in the video clip. The clip can be found by clicking on the
Scientists want to know why some animals are They discovered that the cells next to a link below and then clicking the video tab.
Think of deer. The males have large and able to regenerate, and others are not. wound change. Now they can do any job.
powerful antlers. They shed these antlers in http://kids.nationalgeographic.com/kids/animals/creaturefeature/
winter. In spring, new and bigger ones grow To find the answers, scientists study animals’ The cells then grow and divide. They get salamander/
back. To make new antlers, a deer grows bone, cells. Every living thing is made up of cells. signals from what’s left of an injured body
nerves, and blood vessels. Cells are like microscopic building blocks. part. The signals tell the cells what to do.
Animals begin as one cell. That cell divides Some become bone. Some become muscle.
Male puffins are another example. Their into two cells. Those then divide into four, and Others build blood vessels and nerves. A new
beaks are brightly colored with yellow, red, so on. To understand what triggers healing, body part grows.
and blue-gray stripes. In the fall, these birds scientists look at what happens to the cells
shed the outside of their beak. Underneath, when an animal is injured. Sometimes the new body part isn’t quite
there is a smaller, duller-looking beak. The like the old one. Sure, a lizard can grow a new
next year, puffins grow the colorful part back. As animals grow, most cells get specific jobs. tail. However, the new one is usually shorter
Some cells form skin. Others form muscle, or and stumpy looking. Sometimes the cells get
This kind of regeneration may not be as nerves, or bones. They grow into all the body’s confused. An insect that needs a new antenna
dramatic as growing a new leg. Yet it can be just parts. Once a cell gets a job, that’s often its might grow a new leg—on its head!
as important. The deer with the largest antlers job forever. A skin cell is always a skin cell. A
have an advantage when they compete with muscle cell is always a muscle cell. There’s no Despite these mistakes, regeneration can
others to find a mate. A brighter beak can also going back. Or so scientists once thought. be a lifesaver. It helps people, too. Parts of the
attract mates for the puffin. liver can regrow if it is damaged. Broken bones
mend. New skin covers a wound. Can our
Each fall, the male puffin sheds the outer layer of its beak. bodies do more? Sometimes the
Within a year, the beak will grow back. regeneration
Life Lessons process doesn’t
work quite right. Comic Strip Split the class into small groups. Ask each group to
Today, many questions remain. Exactly how do Instead of one pick an animal that can regenerate a lost body part. Next, direct the
cells get the information they need to grow new tail, this gecko is groups to create a comic strip that shows an animal in the story going
body parts? Is the ability to regenerate hidden regrowing two! through the process of losing or injuring a body part, then regenerating
deep in human cells? it. Explain that each frame of the comic strips should depict a realistic
7JaNuary-February 2011 scene of what might really happen to the animal they picked. Encourage
Only time will tell if people will ever be able additional research if necessary. Distribute the student activity sheet on
to grow new arms, legs, or other body parts. page T15 to use for the comic strip.
We can still learn a lot from salamanders, sea
squirts, and other regenerators. As for the sea
cucumber and its exploding guts, well, that
might be something we don’t want to learn
how to do.

Wordwise

autonomy: ability to let go of a body part on purpose
cell: smallest living part of a plant or animal
invertebrate: animal without a backbone
regeneration: ability to repair or regrow injured or lost body parts

6 NatioNal GeoGraphic explorer

Explore Science EngagE name:

Explain to students that cells are essential for life and Create a Comic
make up all living plants and animals. Have students
work in pairs to create a word web with “cell” in the Choose one of the animals in the “Second Chances” story that has the ability to regenerate. In five scenes,
center. Allow time for students to review pages 6 and create a comic strip showing how the animal goes through this process in its natural environment.
7 to add information to their webs. Place students
in small groups to review their word webs. Have one 12
volunteer from each group share their web with the
whole class. 34 Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.

Remind students that scientists study many 5 Draw your final scene on the back of this paper.
important things like cells. Ask them to think of what
characteristics a good scientist needs. In small groups, T15 NatioNal GeoGraphic pathfiNder
have students brainstorm ideas. (Possible responses: JaNuary-february 2011
curious, good observer, ability to ask questions and
take notes, etc.) To extend the activity, have volunteers Comprehension Quick Check
act out what each characteristic would “look like” in
action. What part do cells play in regeneration of animal body parts?
(Each cell has a job to do when a body part is injured or lost;
remaining cells begin to grow or heal that body part.)

T4

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Bigger, Better Life’s Building Blocks Going Back in Time Extend the Learning

Some animals grow new body parts only after It’s easy to see why being able to grow new When scientists took a close Prefixes Explain that a prefix is a word part added to the beginning of
an emergency. Others do it every year. It’s part body parts can help animals. Figuring out how look at injured salamanders, a word. It changes the word’s meaning. Direct students’ attention to the
of their natural growth cycle. they do it puzzled scientists for a long time. they found something surprising. word “regrow” in the second paragraph under “Smart Parts” on page 4.
Scientists want to know why some animals are They discovered that the cells next to a Display the word “regrow” and circle the word part re-. Explain that re- is
Think of deer. The males have large and able to regenerate, and others are not. wound change. Now they can do any job. a prefix. It can mean “again” or “once more.” Ask students to come up
powerful antlers. They shed these antlers in with their own examples of words that begin with the prefix re-.
winter. In spring, new and bigger ones grow To find the answers, scientists study animals’ The cells then grow and divide. They get
back. To make new antlers, a deer grows bone, cells. Every living thing is made up of cells. signals from what’s left of an injured body Direct students’ attention to “around” in the last line of the first paragraph
nerves, and blood vessels. Cells are like microscopic building blocks. part. The signals tell the cells what to do. on page 4. Ask what does “around” mean? (in a circle) Ask students to
Animals begin as one cell. That cell divides Some become bone. Some become muscle. scan pages 4 and 5 to look for other words with prefixes. As they find
Male puffins are another example. Their into two cells. Those then divide into four, and Others build blood vessels and nerves. A new each word, have them tell what it means. Some other examples from
beaks are brightly colored with yellow, red, so on. To understand what triggers healing, body part grows. the text include: discovered, defeated, regenerate, regeneration, and
and blue-gray stripes. In the fall, these birds scientists look at what happens to the cells invertebrates. Next, give students time to write down other words that
shed the outside of their beak. Underneath, when an animal is injured. Sometimes the new body part isn’t quite use the prefix re-. Divide students into pairs and ask them to come up
there is a smaller, duller-looking beak. The like the old one. Sure, a lizard can grow a new with other words that begin with the prefixes a-, dis-, de-, and in-. Invite
next year, puffins grow the colorful part back. As animals grow, most cells get specific jobs. tail. However, the new one is usually shorter volunteers to share their work with the class.
Some cells form skin. Others form muscle, or and stumpy looking. Sometimes the cells get
This kind of regeneration may not be as nerves, or bones. They grow into all the body’s confused. An insect that needs a new antenna Creative Writing Explain to students that a caption is important
dramatic as growing a new leg. Yet it can be just parts. Once a cell gets a job, that’s often its might grow a new leg—on its head! because it gives readers more information about the picture. Ask
as important. The deer with the largest antlers job forever. A skin cell is always a skin cell. A students to sketch three new pictures that go with the story. Then have
have an advantage when they compete with muscle cell is always a muscle cell. There’s no Despite these mistakes, regeneration can them write captions that go with the three pictures.
others to find a mate. A brighter beak can also going back. Or so scientists once thought. be a lifesaver. It helps people, too. Parts of the
attract mates for the puffin. liver can regrow if it is damaged. Broken bones Pick Two Have students think of two words that come to mind when
mend. New skin covers a wound. Can our they think about the story. The words can either be in the story or
Each fall, the male puffin sheds the outer layer of its beak. bodies do more? Sometimes the something that expresses their thoughts about what they read. Next,
Within a year, the beak will grow back. regeneration have students write down their two words and explain why they picked
Life Lessons process doesn’t those particular words. Invite students to share their responses.
work quite right. (Example response: regeneration and amazing: “I picked regeneration
Today, many questions remain. Exactly how do Instead of one because it describes how some animals regrow missing body parts and
cells get the information they need to grow new tail, this gecko is amazing because it is really cool.”)
body parts? Is the ability to regenerate hidden regrowing two!
deep in human cells?
7JaNuary-February 2011
Only time will tell if people will ever be able
to grow new arms, legs, or other body parts.
We can still learn a lot from salamanders, sea
squirts, and other regenerators. As for the sea
cucumber and its exploding guts, well, that
might be something we don’t want to learn
how to do.

Wordwise

autonomy: ability to let go of a body part on purpose
cell: smallest living part of a plant or animal
invertebrate: animal without a backbone
regeneration: ability to repair or regrow injured or lost body parts

6 NatioNal GeoGraphic explorer

Explore Science continued

Remind students that deer and puffin are examples of
animals that grow new body parts each year. Explain
that regrowing antlers or beaks is not like regrowing
a lost part, yet they have similar results. Ask students
to explain why the two are similar. (Both help animals
survive. Replacing a lost body part helps an animal get
food or keep from being eaten.)

Comprehension Quick Check

What part do cells play in regeneration of animal body parts?
(Each cell has a job to do when a body part is injured or lost;
remaining cells begin to grow or heal that body part.)

T5

PATHFINDER EDITION JANUARY-FEBRUARY 2011

ICEON THIN Comprehension Strategy: As you LIFE ScIEncE Before Reading
read this story, look at the text and
pictures. Look for details. Ask Preview and Predict Use the title, pictures, and captions to help
yourself: “Which details are students predict what they will be reading about. Read the title aloud
and encourage students to flip through the story. Have students predict:
the most important?” What do you see in the pictures? What do you think this story is about?
Have students share possible answers. Encourage them to provide
details. Then have students write down their predictions of what they will
learn from reading “On Thin Ice.”

by Johnna Rizzo 9 Comprehension Strategy

8 Make Inferences Direct students to look at the pictures on pages
10−11. Ask: What kind of animal does it show? What else is in the
picture? Discuss how these clues help students figure out more about
the animal’s environment. Clarify that sometimes we need to look at
details to figure out, or make inferences about, unstated information.
Explain that you can make inferences when you read, too.

On Thin Ice Point out that writers directly tell some details, but they also leave other
things unsaid. Explain that in this story, students will need to think about
About the Story what the author is saying and what the author is leading them to think.
Display these three ideas to help students as they read.
In this story, readers will learn about the lives polar
bears lead in the wild. What is their favorite food? How • Look for details in the text. CompreheNsioN strategy Name:
big do they get? Where do they live? They will also • Think about what you already know about the
read about how global climate change is changing the What’s It Mean?
polar bear’s habitat and how that is threatening the details and topic. Ask yourself: How does what Find examples of text in the “On Thin Ice” story where you believe something
polar bear. I know fit together with this information? important is being said, but not directly. Note key words or phrases that help you
• Put your ideas together. Try to figure out the figure out the author’s intended meaning. Then write what you infer or think the
unstated meanings. hidden meaning really is.

To help students better understand this I think there is something Key words or phrases that help Combining what was said and
strategy, distribute the student activity important being said here: me infer what is being said: what I think the author means:
on page T16. Model the example. Have
students work with partners to complete Example: Scientists measuring temperatures; alarming trend Temperatures are changing in
the activity. Encourage them to share Arctic temperatures have the Arctic, and this is not a
their examples and inferences. discovered an alarming trend. good sign. This may cause
problems.

Sum Up: What do you think the author is saying about the effects of climate change on polar bears? Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.

_____________________________________________________________________________________

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T16 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011

T6

PATHFINDER EDITION JANUARY-FEBRUARY 2011

A lumbering bear plods along an ice floe. Waiting for the Ice Academic Vocabulary

Swimming under the ice, seals can hear it. When ice forms over the sea, it doesn’t make an Display the vocabulary words: blubber, habitat, pack ice, and still
They don’t want to come up for air as long as even layer like on a skating rink. At first, the ice hunting. Instruct students to find each highlighted word in the story. In
that hungry polar bear is there. is thin enough for the wind and waves to break pairs, have them review the definitions for each word from Wordwise
it into pieces. on page 15. Then explain that each student pair will become Wordwise
The bear can smell them. A polar bear can experts. They will study one key word and create a poster. Assign each
smell seals from more than one kilometer As the pieces of ice get colder, they get pair a key word. Remind students that each poster should include
(0.6 miles) away and under one meter thicker. They join together to make larger • the key word and the definition;
(three feet) of heavy snow. blocks. As winter comes, the blocks freeze • a picture and a context sentence.
together, forming pack ice. Invite volunteers to share their posters.
This bear scans the horizon and finds Finally, have students add these words to their Academic Vocabulary
what it is looking for. It sees a hole in the ice. Most polar bears live and hunt on pack ice. Logs or to your classroom science word wall.
It’s a breathing hole. Seals use a dozen or Pack ice is usually about three meters (ten feet)
more holes at one time. The bear knows that thick. It is strong enough to hold a polar bear’s Fast Facts
eventually a seal will pop up for air. It just has weight, as well as that of many arctic animals.
to be really quiet and really patient first. •A polar bear’s fur is not really white. It is made of hollow hairs that reflect
Many polar bears live in southern regions light and trap the sun’s heat to keep the polar bear warm.
Tucking its massive legs beneath its body, of the Arctic. There, the pack ice melts in •Polar bear fur is oily and water repellent which helps them dry quickly after
the bear sits on the ice. Its nose stretches the summer. In places where the ice melts a cold swim.
forward within reach of the hole. It waits. And completely, polar bears move onto land. •Polar bear paws are rough to help keep them from slipping on ice.
waits. And waits. All is quiet.
Land isn’t the best place for polar bears Comprehension Quick Check
More than an hour passes. Then, in an because they’re cut off from their main food
instant, an unlucky seal pops out of the hole supply. Their ideal habitat is floating slabs of Why is pack ice such an important part of a polar bear’s habitat?
to catch a breath. In that same instant, the ice close to the water, which teems with fish (Pack ice is thick enough to hold the weight of a polar bear. It’s where
polar bear pounces. Dinner has arrived. and seals. they hunt for seals by “still hunting.” )

A polar bear’s life is all about dinner. What’s A polar bear pokes through TeBrreitaorry
for dinner and what time is dinner? Dinner must ice in the Arctic.
be caught, however, so the answer depends Polar Bear Range
on the bear. The easiest way for a bear to find Asia
a meal is on ice. Waiting by a breathing hole is
called “still hunting.”

Putting on the Pounds The Ice Kingdom Pacific Ocean North ntic Ocean
America Atla
Under good hunting conditions, a polar bear Wild polar bears are found only in the Arctic.
This polar bear is usually will eat one seal every four or five days. The Arctic is the region around Earth’s North
“still hunting.” One bear can eat 45 kilograms (100 pounds) Pole, which sits in the middle of the Arctic
of blubber, or fat, in one sitting. Eating the fat Ocean. The Arctic covers an area almost equal
from the bodies of its prey adds blubber to the in size to North America. It is bitter cold there.
bear’s body. In winter, it is often sunless. Temperatures can
fall to −40° Celsius (−40° Fahrenheit).
For a polar bear, fat is where it’s at. Blubber
helps keep it warm. Female polar bears weigh In some places, the water in the Arctic is
150 to 300 kilograms (330 to 660 pounds). 4,000 meters (more than 13,000 feet) deep.
Males usually weigh double that. Much of Although it is an ocean, you could walk
that weight is blubber. A healthy polar bear across it. It’s so cold, the surface freezes into
can pack on as much as 11 centimeters ice. To understand polar bears, you need to
(four inches) of fat a year. understand ice.

10 JaNuary-February 2011 11

Explore Science

Understanding how polar bears live and survive is key
to understanding some of their current challenges.
In pairs, have students review pages 10 and 11.
Then have students write responses to the following
questions about polar bears.

• What is the story about? (polar bears)
• Where do they live? (in the Arctic)
• What is their main source of food? (seals)
• How do they get their food and how much do they eat?

(“still hunt” on pack ice; one seal every four or five days)
• Why do they need to eat so much? (to add fat, or blubber, to

stay warm)

Assign students to make ice at home. Tell them to fill
a clear plastic cup with water and place it in a freezer.
Have students check on the cup every two hours. Have
them note the changes they observe. The top edges of
the water freeze first. Then layers of ice form. Some ice
floats on top of the water before the rest freezes.

T7

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Too Hot to Handle? Dangerous Ice A polar bear uses its large, Engage Students
webbed paws to swim.
A polar bear’s whole life is tied to the seasonal The problem of an earlier melt goes beyond just Display the poster “The Polar Bear Challenge” and read the statements
changes in Arctic sea ice. A bear can travel having to hunt on land. As pack ice melts, the aloud. Have students use thumbs up if they believe the statement is true
up to 4,800 kilometers (3,000 miles) a year. It remaining ice is farther from shore. Chunks and thumbs down if they believe it is false.
moves from ice to land to ice again. Yet the ice of floating ice are also farther apart. Now the
may be changing everything for polar bears. gap of open water between the ice and the Encourage students to learn more about the threats to polar bears.
land is larger. A larger gap can make rougher Have them view the following National Geographic video:
Scientists measuring arctic temperatures wave conditions. Waves gush through the gaps,
have discovered an alarming trend. The Arctic tossing ice about. Swimming from shore to http://video.nationalgeographic.com/video/player/environment/threats-to-
is heating up. As it becomes warmer, pack ice pack ice becomes much more dangerous. animals-environment/polar-bears.html
melts earlier in the year. This gives the bears
less time to hunt on the ice, forcing them onto Normally, for a polar bear, swimming long After viewing, have students discuss ideas brought up in the video.
land sooner. Many polar bears cannot find distances comes naturally. A polar bear can Record responses.
enough food on land. swim up to 100 kilometers (60 miles) to get to
a hunting ground. And it’s fast! A polar bear Explain to students that the World Wildlife Fund tracks polar bears to
Hunting on land is hard work. A polar bear can swim up to ten kilometers (6.2 miles) per find out where they are living and how far they move during the year.
might need to stalk, or silently follow, its prey hour to catch a fast-swimming seal. It can dive At the following website, students can follow a great animation about
for long distances. The bear must be careful not as deep as six meters (20 feet) to chase a seal. catching, tagging, and tracking polar bears.
to overheat. This can be a tall order.
Yet even this strong swimmer can tire. wwf.panda.org/what_we_do/where_we_work/arctic/area/species/
As Earth’s largest land predator, a polar bear Rougher seas and greater distances between ice polarbear/polar_bear/tracking/
uses twice the energy to walk than most other floes can prove too challenging for polar bears.
mammals. Just 12 seconds of running can burn With warmer temperatures, a polar bear may Perform a Skit Individually or in small groups, have students create a
more energy than it would get from eating a set out for the next chunk of ice but not be able TV news segment about polar bears. Have students review the story and
whole seal! Stalking that seal for hours, or even to make it safely back to shore. decide on which important facts they want viewers to know about polar
days, can be exhausting. bears. After they write their script, they can present their news segment
to the whole class. Encourage students to use pictures or props if time
A leaping polar bear allows.
barely makes it across
the gap in the ice in Comprehension Quick Check
these photos.
Name three effects warming Arctic temperatures are having on
12 NatioNal GeoGraphic explorer JaNuary-February 2011 13 polar bears. (Possible answers: pack ice melts earlier reducing the
bears’ time to hunt seals; bears are forced on land where there isn’t
Explore Science enough food for them; as ice breaks up, bears have farther to swim,
which is more dangerous)
After reading pages 12-13 of the story, ask: What is our
weather today? Then ask: What is our climate? Help
students identify the difference between weather and
climate. Weather is what is happening today. Climate
is determined by looking at weather data over many
years.

Point out that scientists have been observing the
temperatures in the Arctic for many years. They know it
is getting warmer. These changes are impacting polar
bears. Ask: If the pack ice is melting earlier in the year,
why is that a problem for the bears? (Example: They
are forced onto land sooner and can’t find enough food
to eat.)

T8

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Watching and Waiting Searching for Survival Extend the Learning ExplorE SciENcE Name:

Scientists are tracking the temperatures in the Polar bears are getting so hungry, they are Critical Thinking After reading the story, Cause-and-Effect
Arctic closely. They have found that warming going farther and farther south to find food. have students work with a partner to Think about the cause and effects that you read about in the “On Thin Ice” story. Describe them
temperatures are causing the pack ice to melt This brings them closer to people. As bears discuss the inferences they made while in the boxes provided. Some answers are provided to help guide you.
an average of two weeks earlier than it did just move into places people live, they’ve made a reading. Encourage them to explain
20 years ago. new food find—garbage. how making inferences helped them Arctic temperatures rise.
understand what they read.
That might not seem like a lot, but to a Garbage may be an easy source for food, but Pack ice melts earlier.
polar bear, a few weeks makes a big difference. it is not healthy for bears. It doesn’t give them
It means using more energy to hunt on land the fat they need to survive. It also puts them in Figurative Language Writers play
and finding less fatty foods. For each week the close contact with people. Humans are the only with words to make reading more fun.
ice breaks up earlier, the bears come ashore predator bears need to fear.
weighing nine kilograms (22 pounds) less than
they have in past seasons. What does the future hold for polar bears?
We don’t know. Polar bears have a history of
As Earth gets warmer, hunting time gets survival. Long ago, they probably lived like
shorter. Scientists measuring summer ice in brown bears in warmer regions. Their eating
2010 reported a large melt by June. The ice habits changed when they moved north onto
continued to melt into September, when it the Arctic ice. They adapted to survive.
normally begins to freeze over.
Today, scientists know of 19 groups of polar
For polar bears, warmer weather could mean bears. They have studied 12 of them. Eight
disaster. They have to find enough food to groups have gotten smaller over time. Three
survive the warmest months. Already in some groups are holding steady. One group has
areas, the bears must eat enough in only three grown. This gives some hope that polar bears
or four months to last the rest of the year. That will survive despite the challenges they face
means they go months eating nothing at all. in a warmer world.

Bears are forced onto land.

One way is by using idioms. Explain to There is less food for bears Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
to find to eat.
students that the words that make up
WORDWISE
an idiom mean something different from
blubber: layers of fat
habitat: place where an animal lives what they mean by themselves. For Bears may die out.
pack ice: floating ice that has been driven example: You might say, “Don’t get bent
A polar bear cub together into a single mass
clings to its mother. still hunting: method of hunting out of shape.” Point out that this phrase T18 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011
14 NatioNal GeoGraphic explorer JaNuary-February 2011 15

Explore Science has a literal, or actual meaning, (to be

Invite a volunteer to read aloud the first two bent into a different shape) as well as a figurative meaning (don’t be so
paragraphs on page 14 in the section “Watching and
Waiting.” Tell students that because of temperature upset). Then have students think about the title of this story, “On Thin
changes, scientists are noticing the impact on
many aspects of life in the Arctic. Explain that chain Ice.” Ask: What two meanings could this title have?
reactions are beginning to occur. These are called
cause-and-effect reactions. Say: The cause is what Research Invite students to research other animals that live in the
makes something else happen. The effect is what Arctic and have them tell the class how climate change is affecting
happens as a result. (For example: If the Arctic is those animals. Ask: Why might it be important for us to understand the
warmer, the pack ice melts earlier and bears have changes that climate change is causing? (Possible answers: We want
less time to hunt.) to know how climate change will affect plants and animals in nature. We
want to know how it will affect us and the communities in which we live.)
Distribute the Cause-and-Effect activity on page T18
for students to use as they reread the story. Lead Comprehension Quick Check
students to understand that some effects create the
next cause and the cycle continues. Why do scientists have some hope that polar bears will survive
in spite of the challenges they face? (Possible answers: They have
adapted in the past when they moved from warmer climates to the
Arctic. Of the 19 groups studied, one group has grown and three have
stayed the same size.)

T9

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Comprehension Strategy: As SPAcE ScIEncE Before Reading
you read, look for words that
describe how things look and Activate Prior Knowledge Say: You already know many things about
feel. Use the words to create space and our solar system. Write on a piece of paper what you know.
pictures in your mind. Allow students three minutes to write down everything they know
about space. They can write words or short phrases. When students
SPACE have completed their quick write, use their responses to create a class
QUEST content web. Cluster responses by categories (planets, moon, sun,
stars, etc.), so students can see what they already know.
Blast off with an astronaut
on his journey into space. Leave the content web displayed. Explain that you will be revisiting it
after reading the story and adding new information that is learned.
by Don Thomas
Comprehension Strategy
NASA Astronaut
Determine Importance Explain that when you tell a friend about a
16 17 good movie, you talk about the main idea and details. When you read,
you can do this, too. Summarizing details can help you stay focused on
Space Quest the most important ideas.

About the Story Have students identify the topic of the story. Ask them to skim through
the pages looking at the headings, repeated words, pictures, and
Can you imagine seeing 16 sunrises and sunsets each captions for clues. Next, read aloud the first few paragraphs of “Space
day? Readers will join NASA astronaut Don Thomas as Quest.” Ask: What is the main idea of this section? What are the
he rides space shuttle Columbia into space. He shares important details?
the amazing sights he encounters on his journey,
including stars, sunspots, solar flares, and auroras. Copy the activity on page T20, Comprehension strategy name:
How is a star formed? What happens when a star runs then distribute. After having
out of fuel? These and other stellar facts about our students assemble their cubes, Cube Toss Cut out the reading cube below, fold on the dashed lines, and tape the
galaxy will be explored as Thomas reports back to have volunteers take turns tabs. As you read the “Space Quest” story, stop at the end of each section
planet Earth. reading aloud the story, pausing or page and toss the cube. On a separate sheet of paper, complete the
after each paragraph, section, sentence using what you read in the story.
or page. Then each student
should toss the cube and tape tab fold lines
complete the language frame
on a piece of paper. When I think the author
finished reading the story, check wants me to
in with students to see how this understand . . .
activity helped them determine
what was important. tape tab tape tab

A new word I One thing I found One important Top Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
learned is . . . confusing in this part fact I didn’t know
was . . . before is. . . This information
reminds me of . . .

tape tab After reading this tape tab
part I wonder . . .

tape tab T20 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011

T10

PATHFINDER EDITION JANUARY-FEBRUARY 2011

I had been waiting for this moment since Sunrise, Sunset Bright arches of hot, glowing gas Academic Vocabulary
erupt from the surface of the sun.
I was six years old. I was lying on my back, I unstrapped myself and floated to a window. Display the vocabulary words: axis, galaxy, gravity, rotation, star, and
strapped inside my seat in the space shuttle Nothing could have prepared me for what I telescope. Ask: Do you have ideas about what these words mean?
Columbia. It was minutes before launch and saw. As I pressed my nose to the glass, I gasped. Accept student responses, then clarify by inviting a volunteer to read
my first trip into space. The view took my breath away. the definitions on page 23. Have students add these words to their
Academic Vocabulary Log.
Six seconds before liftoff, the three main The velvety blackness of the sky jumped out
engines roared to life. My seat bucked. It at me. It was darker than any color I had ever Synonyms Display the following words: dynamic, dim, orbit, collide,
rattled. It rolled. If I hadn’t been strapped in, seen. The inky darkness seemed like it was shimmer, churn, gasped, and constant. Explain that these words are
the rumbling would have tossed me to the floor. glowing black. A bright blue layer of Earth’s used in “Space Quest.” Individually or in pairs, have students choose two
atmosphere met with the blackness of space. or three words to look up in a thesaurus. Using the synonyms they found,
Columbia blasted skyward. At that moment, have students create word webs for each vocabulary term. Instruct them
I felt like there was a hand on the middle of my Before long, I saw the first of many sunsets to place a star next to the synonyms in their word webs that most closely
back. The hand was pushing me straight up into from the shuttle. Sunset and sunrise is much match the way the words are used in the story. Encourage volunteers to
the sky. Columbia sped upward. I was yelling different in space. share their word webs and talk about the word meanings.
inside my helmet, “Yahoo! Let’s go!” No one
could hear me over the engines. On Earth, we can see one sunrise and one To extend the activity, have students write sentences for the words they
sunset each day. This is caused by Earth’s chose. Then have them rewrite the sentences replacing each word with a
Eight and half minutes later, everything went rotation, or spinning on its axis. It takes synonym.
silent. The main engines shut down. Another 24 hours for Earth to complete one rotation.
wave of excitement hit me as I realized I’d made Fast Facts
it. I was in space. Now I was eager to get my The shuttle orbits, or goes around, Earth
first view of Earth from space. every 90 minutes. That means I could see • Our 4.5 billion-year-old sun is 110 times larger than Earth and mostly made
16 sunrises and sunsets each day. During my of hydrogen and helium gases.
trip, I could have seen more than a hundred.
• Earth orbits the sun at 107,343 kilometers (66,700 miles) per hour.
Earth’s atmosphere changes color Our Star, the Sun Spots and Flares • We can only see about 6,000 of the over 100 billion stars in our galaxy with
as the sun sets. the naked eye.
The space shuttle whips around Earth at With the unaided eye, the sun looks quiet
28,000 kilometers (17,500 miles) per hour. At and calm. You can see something completely Comprehension Quick Check
that speed, sunsets seem to happen much faster different through a telescope. Now the sun
than they do on Earth. They happen so quickly, looks dynamic. Gases boil and pop. Fiery What is the surface of the sun like? What are sunspots and solar
you could easily miss one. In only 13 seconds, storms rage across its super-hot surface. flares? (The sun’s surface is a storm of boiling and popping gases.
I saw Earth’s atmosphere change from daytime A sunspot is a cooler area on the sun that looks like a dark blotch.
blue to orange to deep red to nighttime black. One kind of storm, called sunspots, looks A solar flare is exploding gases that shoot into space from the sun’s
like dark blotches. A sunspot looks dark surface.)
From Earth or the shuttle, the sun is the because it is cooler than the areas around it. At
brightest object in the sky. It is also the largest times, many sunspots speckle the sun. At other
object in our solar system. One million planets times, there are few or no spots. The number of
the size of Earth could fit inside it. spots follows an 11-year cycle. Right now, we
should be able to see more and more spots.
Yet the sun is just an average-size star. Stars
are giant balls of hot gases. These gases are a Solar flares often form around sunspots.
star’s fuel. Stars change their fuel into energy. A solar flare forms when gases and energy
We see and feel some of this energy as heat and explode from the sun’s surface. The jet of
light. Most stars have enough fuel to make heat energy shoots into space. It reaches Earth in
and light for billions of years. just a few days.

Light flows from the sun and travels through Colliding with Earth’s atmosphere, the
space. It takes a little more than eight minutes energy streams toward Earth’s poles. It causes
for the sun’s light to reach Earth. That means gases in the atmosphere to glow, green, blue,
the sunlight you are seeing right now left the red, and even pink. We call these shimmering
sun about eight minutes ago. colors auroras.

18 NatioNal GeoGraphic explorer JaNuary-February 2011 19

Explore Science

After reading pages 18-19, ask: Where does the sun
rise at your house each day? Where does it set?
Explain that although it seems like the sun rises and
sets each day, it actually does not. The sun stays fixed
in our solar system. It is Earth that does all the moving.

Demonstrate Earth’s rotation around the sun. Ask a
student to stand in place to represent the sun. Then
using a ball, show students how Earth rotates so that
all sides face the sun at some point during the day or
in 24 hours. Then have a student hold the ball, turning
it slowly as you use a smaller object to represent the
shuttle orbiting Earth every 90 minutes. Ask: How does
this demonstrate why astronauts can see 16 sunrises
and sunsets each day?

T11

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Our Solar System A Star Is Born New stars are being born Streams of gas swirl Engage Students
in the Carina Nebula. around Jupiter, the
Energy from the sun not only warms Earth. It Some of the most eye-catching pictures from largest planet in our Art and Space Ask students if they have ever seen a beautiful sunrise
warms all the planets. A planet is a large space Hubble show nebulae. A nebula is a cloud of solar system.. or sunset. Have several students share where they were at that moment.
object that orbits a star. In all, eight planets gas and dust in space. Nebulae form amazing Explain that they are going to create a flipbook with seven or more
orbit our sun. Four of these planets are small, shapes and can have brilliant colors. 21 colored drawings of a particular location as the sun is slowly rising
rocky worlds. They’re called the inner planets. or setting. Point out how subtly the colors need to change as the sun
The other four are gas giants. They’re called the Some nebulae are nurseries for stars. The moves in each frame of the flipbook.
outer planets. Carina Nebula is one of the best known
nurseries. From Earth, it can only be seen from Creative Writing Have students imagine they are astronauts. Direct
Jupiter is the largest of these worlds. It has a the Southern Hemisphere.
ring and more moons than any other planet. It them to write a Space Log using page T21. Encourage them to choose
also is almost completely made of gases. These Stars form inside this nebula and others like
gases move constantly. Colorful clouds churn it. Bits of gas and dust come together. Gravity
around storms. Bolts of lightning streak. The pulls in more and more gas and dust, molding
Great Red Spot, the largest storm on any planet them into a sphere.
in the solar system, whips around. Auroras
even shimmer above the planet’s poles. The sphere grows larger and larger.
Eventually the sphere’s gravity grows so
Star Light, Star Bright powerful that the sphere collapses into itself.
As it collapses, the gases grow hotter and
From the space shuttle, I had a grand view of hotter. If they reach tens of millions of degrees,
the sun, Earth, and other planets. I also could a star is born! Of course, this doesn’t happen
see many more stars than I could ever see from all at once. It takes millions of years for a new
the ground. star to begin to shine.

On Earth, the atmosphere blocks some of Hubble Space
the light from each star. The atmosphere not Telescope
only dims starlight, it changes it. Moving gases
cause stars to twinkle. In space, stars don’t a section of the story that interests them most. Then have students use
twinkle. They look like steady points of light.
details from that section to write an astronaut’s Space Log. Remind
From the shuttle, I could see stars of
different colors. They were white, blue, red, and them to use the first-person point of
even yellow, like our sun. Color tells a lot about
a star. For example, it can tell you how hot a view and include the following items: WRITING Name:
star is. Cooler stars are red. Warm stars are • the date
yellow. The hottest stars are blue. My Space Log

Since we can see stars more clearly from
space, NASA has placed telescopes
there. The Hubble Space Telescope
is probably the best known space
telescope. Launched into space more
than 20 years ago, Hubble can see objects
50 times fainter than the most powerful
telescope on Earth can see.

So far, Hubble has orbited Earth many times.
It has traveled nearly five billion kilometers
(three billion miles). Along the way, it has taken
hundreds of thousands of pictures of objects
in space.

20 NatioNal GeoGraphic explorer • thoughts and feelings
• vivid description
• facts from the story Imagine that you are an astronaut. Write a space log about your experiences.
Be sure to include facts from “Space Quest.”

Explore Science Date: ________________ Date: ________________
___________________________________ ___________________________________
Have students work in pairs to list all the planets in our ___________________________________ ___________________________________
solar system in their correct order. After a few minutes,
ask volunteers to read their list. Display the correct ___________________________________ ___________________________________
answer. (Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, Neptune) Have volunteers share their Space ___________________________________ ___________________________________
___________________________________ ___________________________________
Tell students that a mnemonic can help them remember
something. By using the first letter of each word in Logs. Ask: What details make the entry ___________________________________ ___________________________________
the following mnemonic, students can remember the interesting or exciting? ___________________________________ ___________________________________
order of the eight planets in our solar system. “My Very
Excellent Mother Just Sent Us Noodles.” These letters Date: ________________ Date: ________________
stand for Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, and Neptune. ___________________________________ ___________________________________ Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.

___________________________________ ___________________________________

___________________________________ ___________________________________

___________________________________ ___________________________________

___________________________________ ___________________________________

___________________________________ ___________________________________

___________________________________ ___________________________________

T21 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011

Comprehension Quick Check

Why are stars different colors and what does it mean? (The color
of a star tells its temperature, or how hot it is. Cooler stars are red,
warm stars are yellow, and the hottest stars are blue.)

T12

PATHFINDER EDITION JANUARY-FEBRUARY 2011

Dying Stars Galaxies Ahead Billions of stars make up the Whirlpool galaxy. Extend the Learning
Its curving spiral arms house young stars.
Most stars live for millions or billions of years. A group of millions of stars is called a galaxy. Older stars shine in its yellowish core. ABC Book Have students form groups of three or four and
How long a star lives depends on how big it is. In our own galaxy, the Milky Way, the sun is brainstorm all the things they can think of that exist in space that
The largest and hottest stars have the shortest just one of about 100 billion stars. start with letters A-Z. Then have students divide up the pages and
lives. These stars live for only a few million make an ABC Book about space for students in younger grades.
years. Smaller stars tend to live longer because Hubble has shown us some spectacular Note: For any difficult letters, they can use adjectives that describe
they don’t use up their fuel as fast. Our sun is examples of galaxies. Many are spirals like space or something connected to it. (Example: Q – quiet)
about halfway through its life. We expect it to the Milky Way. One is shaped like a tadpole. Note: Each page should include a letter, word, and picture.
burn for another five billion years. Another looks like the eye of a cat. Research Provide students time to research planets using text
or online resources. Then have students answer the following
A star’s size also affects how it dies. When From Columbia, the sky looked alive with question: Which planet would you like to visit and why? Remind
a star the size of our sun runs out of fuel, it more stars than I could ever count. A couple students that their answer should include specific information they
puffs out its outer layers of gas. It slowly dims. of my favorite things to see were the Large have learned about the planet they researched.
Eventually it becomes a black dwarf—a frozen and Small Magellanic Clouds. They are a pair Content Web Have students revisit the content web created
ball floating through space. of small galaxies that orbit the Milky Way. A during the “Before Reading” exercise. Ask students about
small galaxy has fewer than a billion stars. additional details they learned that should be added to the web.
Some of the largest stars collapse on
themselves when they run out of fuel. The Through a pair of binoculars, I could see Comprehension Quick Check
outer layer of a large star explodes into space. these fuzzy patches of light come into focus. I
The star’s outer layers form a kind of nebula had to look quickly because my view was about What determines how long a star will live? (How long a star lives
around the dying star. to change. Another spectacular sunrise was on depends upon how big it is. Larger stars use up their fuel quicker,
its way. The light and heat felt good on my face thus smaller stars live longer.)
The largest stars have mysterious endings. as the sunlight streamed through the windows
Gravity causes a giant star to collapse on itself. of Columbia.
It collapses so fast and violently that it becomes
a black hole. Gravity squeezes all the star stuff After staring at all the strange and
into a pinpoint. No one knows what happens wonderful sights in the night sky, it was
inside a black hole. We know little about good to see the old familiar sun once again. I
black holes because their gravity is so strong, soon realized that I was a little homesick. As
nothing, not even light, can escape them. amazing as stars, nebulae, black holes, and
galaxies are, there’s no place like Earth.

The Helix Nebula is a ring of gas around An exploding giant star formed the WORDWISE
a dying star. Crab Nebula.
axis: line about which a rotating body such as
22 NatioNal GeoGraphic explorer Earth turns
galaxy: system of stars
gravity: pulling force that all objects have
rotation: act of turning around a center
star: body of hot gases that radiates energy
telescope: device used to study distant objects

23

Explore Science

Display the words solar system, galaxy, universe. Ask
students: Think about the differences between each
of these words. What does each describe? Begin
with solar system and have students name all the
things they can think of that exist in our solar system.
(planets, comets, meteors, moons, stars, etc.) Then
continue with the word galaxy (a large grouping of
stars). Point out that our sun is part of the Milky Way
galaxy and that our solar system is part of that galaxy
as well. Finally ask: What is the universe? (Possible
answers: everything that exists; all galaxies and
nebulae, or clouds of gas and dust)

Ask students: What do you think would be the most
amazing part of being an astronaut? What would be
most challenging? (answers will vary)

T13

Comprehension Strategy Name:

Q&A

As you read the “Second Chances” story, stop at the end of each section. What questions
come to mind? Record your questions and the answers you find in the story below.

Page Question Answer


How did you figure out the answers to your questions? Tell a partner. Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________

_____________________________________________________________________________________

T14 National Geographic Pathfinder
January-February 2011

Engage Name:

Create a Comic

Choose one of the animals in the “Second Chances” story that has the ability to regenerate. In five scenes,
create a comic strip showing how the animal goes through this process in its natural environment.

12

34 Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.

5 Draw your final scene on the back of this paper.

T15 National Geographic Pathfinder
January-February 2011

Comprehension Strategy Name:

What’s It Mean?
Find examples of text in the “On Thin Ice” story where you believe something
important is being said, but not directly. Note key words or phrases that help you
figure out the author’s intended meaning. Then write what you infer or think the
hidden meaning really is.

I think there is something Key words or phrases that help Combining what was said and
important being said here: me infer what is being said: what I think the author means:

Example: Scientists measuring temperatures; alarming trend Temperatures are changing in
Arctic temperatures have the Arctic, and this is not a
discovered an alarming trend. good sign. This may cause
problems.

Sum Up: What do you think the author is saying about the effects of climate change on polar bears? Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.

_____________________________________________________________________________________

_____________________________________________________________________________________

T16 National Geographic Pathfinder
January-February 2011

Comprehension Strategy Name:

What’s It Mean?
Find examples of text in the “On Thin Ice” story where you believe something
important is being said, but not directly. Note key words or phrases that help you
figure out the author’s intended meaning. Then write what you infer or think the
hidden meaning really is. Answers may vary. Here are a few possible examples.

I think there is something Key words or phrases that help Combining what was said and
important being said here: me infer what is being said: what I think the author means:

Example: Scientists measuring temperatures; alarming trend Temperatures are changing in
Arctic temperatures have the Arctic, and this is not a
discovered an alarming trend. good sign. This may cause
problems.

Yet, what if something goes wrong goes wrong I think the author is getting me
with that cycle? ready to find out what might
happen if things go wrong.

Many polar bears cannot find cannot find food I learned earlier in the story
enough food on land to eat. polar bears need to eat a
lot. If they cannot find food,
However, with rougher seas and maybe they will get sick or
greater distances to swim, even a die.
great swimmer like the polar bear
can tire. rougher seas; greater distances; These climate changes are Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
bears can tire making it harder on the bears.
Each week the ice breaks up If they get too tired, maybe
earlier, researchers have found, more bears will drown or
the bears come ashore lighter. starve looking for food.

ice breaks up earlier; bears lighter Polar bears aren’t getting the
food they need and are losing
weight.

Sum Up: What do you think the author is saying about the effects of climate change on polar bears?

_____________________________________________________________________________________

_____________________________________________________________________________________

T17 National Geographic Pathfinder
January-February 2011

Explore Science Name:

Cause-and-Effect
Think about the cause and effects that you read about in the “On Thin Ice” story. Describe them
in the boxes provided. Some answers are provided to help guide you.

Arctic temperatures rise.

Pack ice melts earlier.

Bears are forced onto land.

There is less food for bears Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
to find to eat.

T18 Bears may die out.

National Geographic Pathfinder
January-February 2011

Explore Science Name: answer key

Cause-and-Effect
Think about the cause and effects that you read about in the “On Thin Ice” story. Describe them
in the boxes provided. Some answers are provided to help guide you.

Arctic temperatures rise.

Pack ice melts earlier.

Bears can’t hunt on ice. Bears are forced onto land.

There is less food for bears Bears get into garbage and Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
to find to eat. get closer to humans.

Bears lose weight. Bears may die out.

T19 National Geographic Pathfinder
January-February 2011

Comprehension strategy name:

Cube Toss Cut out the reading cube below, fold on the dashed lines, and tape the
tabs. As you read the “Space Quest” story, stop at the end of each section
or page and toss the cube. On a separate sheet of paper, complete the
sentence using what you read in the story.

tape tab fold lines

I think the author
wants me to
understand . . .

tape tab tape tab

A new word I One thing I found One important Top Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
learned is . . . confusing in this part fact I didn’t know
was . . . before is. . . This information
reminds me of . . .

tape tab After reading this tape tab
part I wonder . . .

tape tab T20 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011

Writing name:

My Space Log

imagine that you are an astronaut. Write a space log about your experiences.
Be sure to include facts from “space Quest.”

Date: ________________ Date: ________________
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___________________________________ ___________________________________

Date: ________________ Date: ________________ Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
___________________________________ ___________________________________
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___________________________________ ___________________________________
___________________________________ ___________________________________

T21 NatioNal GeoGraphic pathfiNder
JaNuary-february 2011

REVIEW Name:

Comprehension Check

Write the correct letter of the word that matches each definition next to numbers 1-6.

____ 1. animals without backbones a. pack ice
____ 2. method of hunting b. still hunting
____ 3. body of hot gases that radiates energy c. invertebrates
____ 4. floating ice that becomes a single mass d. regeneration
____ 5. to regrow lost or injured body parts e. galaxy
____ 6. systems of stars f. star

Read questions 7-9. Circle the correct answer.

7. Which is not a result of warming Arctic temperatures?

A. Bears have less time to still hunt. C. Bears store food in the snow.

B. Bears have greater distances to swim. D. Bears are looking for food in people’s
garbage.

8. An example of autonomy is ….. C. A deer sheds its antlers in winter.
A. A crab drops its claw in a struggle. D. A salamander grows back a damaged tail.
B. A salmon regrows a lost fin.

9. Which statement is true about our sun? C. It is made of molten lava. Copyright © 2011 National Geographic Society. Teachers may copy this page to distribute to their students.
A. Its light reaches us in 24 hours. D. It is only one of a few large stars in the
B. It is just an average-size star.
Milky Way.

10. In the story “Second Chances,” you learned that cells are like microscopic building blocks.
According to the story, explain what role cells play in animals and humans.

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T22 National Geographic Pathfinder
January-February 2011