Answer Keys
for Calvert Math
Core Daily Work
Lessons 1–40
41–60
08COREAKC0610-0615
CONTENTS
Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Reading Activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
History & Geography Workbook . . . . . . . . . . . . . . . . . . . . . . . . . 82
Science Textbook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Science Manual Exercises. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Science Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Please Note: Our History course does not reference questions in the History textbook,
America: History of Our Nation. If you chose to use these as an additional resource,
you can find the answers to the questions in the Learning Guide portal on My Calvert.
Reading
Answer Keys
Lessons 41–60
LESSON 41
LESSON 42
Learning to Read Images Actively
Application
Analyzing Poetic Comparisons
Application
Answers listed are suggestions. As
stated in the directions, the student
should also decide if the image recalls
an experience or presents a new one.
a a = hair
a. sight (ramped) and sound (roared
and alliteration of Rs)
b. sight (bloody foam) and sound
(whisking)
c. sight (dust lifting to show position
of two men)
d. sight (rubbed his hands and many
other examples), sound (tongues
applauded)
e. sight (sneer) and sound (pounds)
f. sight (appearance) and touch
(different textures)
g. sight (clumsy yellow earrings) and
sound (metal)
h. sight (red sun) and sound
(alliteration of Ds)
i. sight (white and ghostly) and touch
(ghostly)
j. sight (pit with sand and mane) and
sound (thunderous smother)
k. sound (wheeze)
l. sight (men carrying chest), smell
(marshes), sound (sucking, gasping),
touch (sunburn, flies, heat) and taste
(longing for a long drink)
m. sound (Tlot-tlot)
n. touch (wool, swan’s down)
o. sound (squalling, squeaking,
howling)
light color of hair
b = champagne or ale
(simile).
b a = she
scream (simile).
b = cockatoo
c a = woman
slender (simile).
b = birch or maple limb
d a = skirts
b = bell
color, shimmer, and shape
(simile).
e a = rotting trees
appearance of trees washed up on shore
b = clothes of corpses
(simile).
f a = Spanish waters
b = piece of music
sweet sound
(simile).
g a = wind
b = torrent
sound and feeling of a rush
(metaphor).
h
a = moon
b = galleon
being tossed around like a boat on choppy seas
i a = road
b = ribbon of moonlight
p. touch (cool, fresh, smooth, fair),
smell (fresh, fair)
q. sight (grain) and smell (rotting)
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color and shape
(metaphor)
(metaphor).
R eading A nswer K ey
L essons 41–60
LESSON 43
j a = sea
b = treacherous smiler
trickiness (metaphor).
“The Destruction of
Sennacherib”
k a = Maquoit Bay
b = shine
rich color and shine
Instruction Rhyme scheme: aabb
(metaphor).
Discussion Questions 1 In the first
stanza, King Sennacherib and his
army pounce on Jerusalem, their
armor and weapons both gleaming
and numerous. 2 A fold is a flock of
chickens or other prey that a wolf
would attack. This lets the reader
know that the Jews are unprotected
and in danger. In addition,
Sennacherib is not attacking by
himself; his army (cohorts) is with
him. 3 In the second stanza, the
Assyrian army is as fresh and
numerous as leaves in a forest. Then
like leaves fallen to earth in the
autumn, the soldiers lie dead. 4 In
lines 9–10, Death personified as an
angel breathed on the soldiers and
they died; there is action. In lines
11–12, death chills the corpses; there
is no action. 5 In the fourth stanza,
Byron describes a war horse frozen in
death, its nostril wide but breathless,
and foam from its mouth splashed on
the ground. 6 The dead war horse in
the fourth stanza seems to belong to
the dead soldier in lines 17–18.
7 Jewish people call non-Jews
Gentiles. Sennacherib and the
Assyrian army are the Gentiles who
are unsmote by the sword. Instead of
being killed in battle, they were killed
by a glance of the Lord.
l a = Cerelle
b = flower, sands, shells
natural beauty (similes).
m a = hair
b = hay
sight and smell of mold
(simile).
n a = face
b = brand
fiery (simile).
o a = irony
b = steel
sharpness (simile).
p a = rocks
b = teeth
ugly shape and old appearance
(metaphor).
q a = fog
b = person
embracing like a person would
(metaphor).
r a = perfume
b = cascade
a waterfall motion
(metaphor).
s
a = birds settling down
b = housewives putting linens away
action of shaking and folding
(simile).
t
a = Hector springing forward
b = eagle diving for prey
a fast, strong, focused, and deadly motion
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(epic simile).
R eading A nswer K ey
LESSON 44
“A Shot at Night”
Discussion Questions 1 Answers will
vary but the image may involve
peacefulness and silence. 2 In line 7,
fear is personified by the word
creeping. People or animals creep.
3 Answers will vary and should be
supported by logical reasoning.
4 Answers will vary but may include
the ideas of shock, shattering, and
jaggedness in sound. The poet
probably used this image twice to
emphasize that something whole has
been violently broken. 5 In lines
8–11, the action halts. There is a
moment of silence that even seems to
affect the stars, moon, and trees.
6 Purnell appeals to the reader’s sense
of hearing in lines 12–14. 7 The
alliterated words, wind and weeping,
in line 14 emphasize the sense of
hearing. Those two words support the
mood of the poem by imitating the
sound of the wind and suggesting an
effect of the gunshot. Perhaps a
person is weeping.
8 Personal opinion should be
supported by specific examples.
LESSON 45
“The Skater of Ghost Lake”
Instruction Rhyme scheme: aabb
Discussion Questions 1 In stanza 1,
a faint sound whirrs develops into line
1 in stanza 2. 2 In stanza 2, lines 6–7
develop into Jeremy Randall in stanza
3. 3 In stanza 3 repetition develops
character. 4 In stanza 4 one example
of alliteration is glass and glides in
line 1. The words that begin with glemphasize ice skating. 5 In stanzas
6–7, the couple is ice skating together
so that it looks like a dance. 6 In
stanza 6, the detail that Jeremy’s eyes
are burning brilliantly is ominous.
7 The noun in stanza 7 that is an
example of onomatopoeia is skurr, the
sound of a metal skate blade on ice.
8 The word lacquered develops the
image of the frozen, black lake by
L essons 41–60
adding shine to it. 9 In stanza 9, the
sense of hearing is appealed to as the
faint sound comes faster and faster.
10 In stanzas 11–13, Jeremy’s
response to seeing something is to
skate faster to the middle of the
frozen lake. 11 In stanza 14, the
sound is quickly following and then
encircling the two skaters.
12 Speculation on what occurs in the
first two lines of stanza 15 will vary.
The description appeals to the senses
of sight, touch, and hearing. In the
last two lines of the same stanza, a
shadowy phantom or a bird veers
away from the scene. 13 Answers as
to why the lake is called Ghost Lake
will vary. The last line ends the story
with an image that echoes the
beginning. The dark scene is fenced
in by trees that seem to keep
something in or keep something out.
14 Answers will vary and should refer
to details in the story. 15 Opinions
should be supported by reasons.
LESSON 46
“The Lady of Shalott”
Discussion Questions Part I
1 The poem is set in a beautiful rural
area with roads and a river running
through the fields to Camelot. 2 The
Lady lives on an island in the middle
of the river. 3 Although no one sees
the Lady, the farm workers sometimes
hear her singing. They call her the
fairy Lady of Shalott. 4 Titles will
vary.
Part II 5 Because the Lady is under
the impression that she should not
look out the window, she occupies her
time by singing and weaving.
6 Answers will vary, but should
include the idea that if the Lady looks
out the window at Camelot,
something bad will happen to her.
7 The Lady sees shadows of the world
in a mirror: the road, the river’s
current, and the young men and
women of the village. 8 The Lady is
dissatisfied when she sees newly
married lovers in her mirror. 9 Titles
will vary.
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Part III 10 Some of the images used
to describe Lancelot are sunlight, a
knight kneeling to a lady on his
shield, stars, and meteors. In
addition, some of the imagery appeals
to the sense of hearing: the bells on
the horse’s bridle, the bugle that could
be sounded, and Lancelot’s singing.
11 Tennyson probably developed the
description of Lancelot to emphasize
how attractive he is. 12 The Lady’s
reaction when she sees Lancelot in the
mirror is to run to her window to see
him. 13 Titles will vary.
Part IV 14 The weather in the first
stanza of Part I is unremarkable; it is
an integral part of the rural scene. It
may be late summer. In Part III the
weather is stormy, and the season may
be autumn as the pale yellow woods
were waning. The difference in the
weather subtly foreshadows that
something bad will happen.
15 Tennyson compares the Lady to a
seer. This simile is appropriate
because she seemed to know about
the curse from a whisper. In addition,
she prepares for her death in a
ritualistic manner as if it were written
down in a book. 16 At first, as the
Lady floats downriver, she stares at
Camelot. Then she lies down in the
boat and sings a song in a chanting
manner. 17 Opinions should be
supported by logical reasoning and
references to the text. 18 Titles will
vary.
LESSON 47
“From This the Strength”
Discussion Questions First stanza
1 Answers will vary but may include
the idea that thick fog can darken
daytime. 2 The rocks are compared to
ugly old teeth in a metaphor.
3 The alliteration of the s-sound
recreates the sound of the sea, which
supports the setting, while at the same
time emphasizing the stillness of the
gulls. 4 The atmosphere of the first
stanza is ominous as developed by the
fog, ugly and aged teeth, discoloured,
hidden, and the silence of the birds.
R eading A nswer K ey
5 In the first stanza, the speaker sets
the scene for the story.
Second stanza 1 Two boys throw
garbage on the rocky shore. In
response, the birds come to life in
sound and motion as they vie for the
food. Afterward, the birds settle
down again. 2 In line 14, the speaker
compares the birds’ beating wings to
butterflies in a simile. 3 In line 19,
the gull’s tail is compared to a comet
curving across the sky in a metaphor.
4 In line 23, the two gulls are
compared, in a simile, to housewives
putting away laundry. 5 In the
second stanza, the speaker describes
the scene or story.
Third stanza 1 In lines 24–25, the
boys leave the shore, and the birds,
after eating the garbage, fly away.
2 Observe that the garbage feeds the
birds, making them strong creatures
that have the strength to handle
challenges in their lives such as wind
currents. Wording will vary but
content should focus on the following
idea. The “garbage” with which
people have to deal can make them
stronger and better prepared to face
life’s challenges. 3 In the third
stanza, the speaker hints at the
meaning of the scene.
LESSON 48
“King John and the Abbot of
Canterbury”
Discussion Questions 1 The king is
jealous of the abbot because the abbot
has more money than the king.
2 The abbot responds that all the
money he spends belongs to him. The
implication is that the king spends
money but it really does not belong to
him; perhaps the money comes from
taxes. 3 The abbot has to answer
three questions. What is the king’s net
worth? How much time will it take for
the king to travel around the world?
What is the king thinking?
4 The shepherd helping the abbot is
ironic because the wisest people at
L essons 41–60
Cambridge and Oxenford could not
help him answer the three questions,
yet an illiterate field worker can.
5 It is important that the shepherd
impersonate the abbot because the
shepherd can then tell the king what
he is thinking: that he is talking to the
abbot. 6 The humor in the shepherd’s
answers saves the abbot’s life. 7 The
king wants to make the shepherd the
Abbot of Canterbury.
8 The king gives the shepherd four
nobles a week; a noble is a gold coin.
9 Answers will vary and may include
that as a leader King John does not
seem to value life, but as a person he
has a sense of humor.
LESSON 49
“Achilles Revenge”
Discussion Questions 1 Hector
jumping forward to engage Achilles
in a personal battle is compared to a
diving eagle. 2 Vulcan, the Roman
god of fire and the forge (known as
Hephaestus in Greek mythology),
made Achilles’ armor. 3 Achilles’
spear is compared to the fairest star in
the night sky, known in Roman and
Greek mythology as Hesperus, or
Vesper. 4 Achilles decides to stab
Hector in the throat. 5 When Hector
dies, his soul goes to Hades, the
underground kingdom in Greek
mythology where all souls were taken
when they died. 6 Achilles removed
Patroclus’s armor from Hector’s body.
Hector had claimed the armor for
himself when he killed Patroclus.
7 The Greek soldiers dishonor
Hector’s corpse by mutilating it.
8 Achilles ties Hector’s body to the
chariot (car) by threading leather
thongs through Hector’s heels and
ankles. 9 Achilles further insults
Hector’s corpse by dragging it behind
his chariot as he drives around in
triumph. 10 Jove or Jupiter is the
Roman name for the Greek god Zeus.
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LESSON 50
Application
The Merchant of Venice
Yes: It bless / eth him / that gives /
and him / that takes
Othello
Yes: Of one / that loved / not wise /
ly, but / too well
Macbeth
No
Julius Caesar
No
LESSON 51
Julius Caesar
Discussion Questions 1 Brutus
means that his love for Rome is
stronger than his love for Caesar. He
helped to murder Caesar because of
his love for Rome, not because he
hated Caesar. 2 *Had you rather
Caesar were living, and die all slaves,
than that Caesar were dead, to live all
freemen? The two opposing situations
are die as slaves under the rule of
Caesar or live as freemen without
Caesar. Brutus assumes that his
listeners will choose to live as
freemen without Caesar. *Who is here
so base that would be a bondman?
Brutus is expecting the crowd to
answer that they want to live the lives
of freemen. *Who is here so rude that
would not be a Roman? Brutus expects
his listeners to want to live as refined
Romans. *Who is here so vile that will
not love his country? Brutus expects
them to choose love of country.
3 Brutus admires Caesar for his
friendship, good fortune, and bravery.
4 Brutus thinks that Caesar’s
ambition is not good for Rome.
5 Brutus says that he has offended or
hurt no one by killing Caesar.
6 Brutus manages to make the
murder of Caesar seem reasonable
because, as he insists that he did it for
the good of Rome, he offers to let
himself be killed if he also is not good
for Rome.
R eading A nswer K ey
LESSON 52
Julius Caesar
Instruction
The valiant never taste of death
but once.
I know not what you mean by that
But those that understood him smiled
at one another
But wherefore do you hold me here
so long
Discussion Questions 1 It is
important for Antony to explain that
he is burying Caesar rather than
praising him because he too is in
danger of being assassinated. He has
just pretended to side with the
conspirators to save his own life. In
addition, Brutus has convinced the
public that Caesar’s death was
essential for the continuation and
success of all that is Rome.
2 In lines 3–5, Antony seems to be
implying that whatever good Caesar
did will end and that whatever evil
Caesar committed will now have to be
dealt with. 3 In lines 5–8, the phrase
that implies that Antony may not be
agreeing with Brutus is if it were so.
4 The verb answered develops at a
high price. 5 In line 13, the alliterated
words emphasize that Caesar was a
good friend to Antony. 6 Caesar’s
virtues as a leader are: made Rome
rich through ransoming captives, had
compassion for the poor, and thrice
refused the title of king. 7 Antony is
communicating that Caesar is
sensitive to the plight of poor people.
The poor people would probably be
too busy surviving to cry, and Caesar
would not actually cry over this
situation. 8 The effect of lines 28–29
on the crowd is probably to catalyze
them into reacting against Brutus.
The lines demonstrate Antony’s sense
of fairness. He distances himself from
Brutus and emphasizes that he speaks
of his own experience. Yet he has just
spent many minutes demonstrating
Caesar’s greatness through the use of
L essons 41–60
irony. 9 In line 32, the alliterated
words emphasize a low level of life,
the life of animals that do not have
the ability to reason. He implies that
the crowd has not used their reason;
they have been “herded” into
supporting Brutus. It is interesting
that the word brutish recalls Brutus’s
name. 10 Antony stops speaking
because he is overcome with grief.
11 The prediction of the crowd’s
response should be supported by
references to specific parts of
Antony’s speech. 12 Shakespeare may
have composed Brutus’s speech in
prose and Antony’s in verse not only
to provide a contrast in style but also
to elevate Antony’s above Brutus’s.
The poetry in Antony’s speech seems
to indicate that his is somehow better
or truer. 13 Opinion should be
supported with specific references to
the speeches.
LESSON 53
Hamlet
Discussion Questions 1 Laertes is
traveling by boat as the words aboard
and sail indicate.
2 A. T B. T C. F D. T E. F F. T
G. F H. F 3 In lines 25–27, Polonius
advices his son to consult his own
heart and think and act accordingly.
If Laertes is true to himself, then his
interactions with others will then be
honest. 4 An analysis of Polonius’s
advice to his son should be supported
by references to the speech and
explanations. 5 From this speech,
which includes advice on clothing,
money, friendship, social interaction,
psychology, and spirituality, Polonius
seems to be the type of person who
needs to address all the facets of a
topic. He has no doubt that his advice
is worthwhile, yet there is no logical
order to the items. Also, he points out
that Laertes is late, but he detains him
with the advice.
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LESSON 54
Hamlet
Instruction Idiomatic translations of
Polonius’s speech will vary.
Application
Those friends thou hast, and their
adoption tried
Speak the speech, I pray you, as I
pronounced it to you
But such officers do the King best
service in the end
Therefore no more but to the matter
And it must follow, as the night
the day
LESSON 55
Henry IV
Discussion Questions 1 Henry does
not want more soldiers because the
fewer the soldiers, the greater their
share of honor. 2 honor 3 The
mythological allusion in line 7 is to
Jupiter or Jove, the king of the gods.
4 Henry’s “best hope” is to win this
battle and then to win the war so that
he can claim parts of France for
England. 5 Henry wants to send any
unwilling soldiers back to England.
This is ironic because the English
soldiers are already outnumbered and
reluctant soldiers are usually forced to
fight or are punished. 6 The old,
retired soldiers will celebrate the
anniversary of this battle with pride.
7 No old soldiers will ever forget the
battle of Agincourt. In fact, they will
be able to recall in detail how they
fought and with whom. They will
toast their fellow soldiers and tell
their battle stories to their sons.
8 Henry builds a sense of community
and comradeship when he calls his
leaders and soldiers his brothers.
Their fighting together in the battle
creates a bond that will never be
broken. 9 English gentlemen, who
missed this opportunity to fight, will
feel regret. They will also feel inferior
R eading A nswer K ey
as the veterans of the battle retell
their stories. 10 Opinion should be
supported by references to the speech
and explanations.
LESSON 56
Macbeth
Discussion Questions
1 Lady Macbeth wonders if her
husband will ever be king because he
is a moral person. 2 Lady Macbeth
thinks that her husband lacks the
ruthlessness that can convert
ambition into success. 3 When
Macbeth really desires something, he
wants to attain it in a right and moral
manner. 4 Lady Macbeth wants to
inject her husband with her own
single-minded resolve.
5 “Metaphysical aid” in line 15
probably refers to the witches. 6 In
lines 21–22, Lady Macbeth is implying
that King Duncan who plans on
leaving tomorrow will never see the
sun rise. He will be dead. 7 Answers
will vary. The look on Macbeth’s face
is so odd that people who see him will
know that something unusual has
occurred. 8 The hidden stage
direction is that Macbeth, without
words, will have a negative reaction to
what his wife is saying about the king
not waking up. Depending on the
actor, Macbeth may bury his face in
his hands, or look startled, or let his
mouth drop open in shock. 9 Lady
Macbeth wants her husband to look
innocent or like a welcoming host.
However, she wants him to act with
the ruthlessness it will take to seize the
throne. The images she uses are a
flower and a serpent. 10 In line 27 he
refers to King Duncan. 11 The king
needs a bedroom for himself, and,
because royalty rarely travel alone,
rooms are needed for the people who
accompany him. Duncan also needs a
meal and entertainment suited for his
station in life. In addition to these
public preparations, private plans must
be made for the king’s murder.
12 Lady Macbeth herself will be
managing the preparations. 13 The
L essons 41–60
preparations will result in the king’s
death. Shakespeare probably alliterated
solely sovereign sway to emphasize the
idea that in the near future Lady
Macbeth and her husband will be the
next queen and king of Scotland.
14 Yes, she is intent on bolstering her
husband’s resolve to do whatever it
takes to be king. Her ambition is so
powerful that she believes that
wickedness is an essential ingredient
in the plan for Macbeth to be king.
LESSON 57
Macbeth
Discussion Questions 1 In the first
excerpt, the phrase “then ‘tis time to
do’t” means it is time to murder the
king. It is 2 o’clock in the morning
when everyone should be asleep.
2 Macbeth seems to be feeling
frightened. She tries to shame him
into courage with “A soldier, and
afeard?” 3 The Macbeths do not have
to fear who knows Duncan is dead
because no one would suspect the
gracious host and hostess of having
killed their royal guest. 4 The “old
man” is the murdered King Duncan.
5 Lady Macbeth asks where Lady
Macduff is. Then she notices that her
hands are not clean, implying that
they are stained with blood. 6 Lady
Macbeth imagines that she is seeing
her husband looking shocked or
having a fit. 7 In the third excerpt,
the reason for Lady Macbeth rubbing
her hands becomes clear. They are
figuratively stained with blood. She
can actually wash blood off her hands
but psychologically her guilt at the
bloodshed she has initiated is making
her replay actions that have actually
occurred. 8 In the fourth excerpt,
Lady Macbeth asks her husband to
look natural to cover up what has
happened. In this case, Banquo is
dead, another bloody victim. 9 Lady
Macbeth tries to assure her husband
that once someone is buried, he
cannot come to life again. 10 King
Duncan has been murdered by the
Macbeths. She wants to get in bed so
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that when the murder is discovered
she and her husband can pretend that
they have been sleeping all night. It
will further enhance their innocent
appearance. 11 Shakespeare may
have chosen prose instead of blank
verse to create a contrast between
Lady Macbeth’s evilly ambitious
character at the beginning of the play
and her pitiful guilt-ridden character
later. The blank verse gives Lady
Macbeth a vehicle to be powerfully
and poetically ambitious.
Contents of lists and informal
paragraph will vary but should
demonstrate the change in Lady
Macbeth’s character. In Act I, Lady
Macbeth is energized and goaloriented, willing to use any means to
attain her end. She analyzes her
husband’s character traits, identifying
which ones he lacks that would help
him be king. She is so filled with
ambition that she wants to infuse her
husband with evil and to murder the
king. In Act V, her guilty conscience
causes her to sleep walk. In that state
she thinks that her hands are stained
with blood. She is obsessed with
cleaning her hands, and she relives
moments from the past that involve
bloodshed and treachery. She is
helpless.
LESSON 58
Romeo and Juliet
Discussion Questions 1 During the
Prince’s first two lines, he is trying to
stop the fighting. Capulets and
Montagues are fighting while others
are trying to stop them. The action
would be matched by sound: sighs,
groans, yells, clashing swords, etc.
2 The Prince might address the first
part of line 3 to one of his servants or
fighting men. He also might be
talking to himself. This is an example
of how an actor can interpret
Shakespeare in different ways.
3 subjects, enemies, profaners, men,
beasts 4 Answers will vary.
5 Fighting has erupted three times.
6 Answers will vary. Temper can refer
R eading A nswer K ey
to a state or habit of mind; anger; or
even calmness! Tempered also refers
to the process by which metals, such
as swords, are hardened. Mis- is a
prefix which means mistaken or
wrong. The mistempered weapons
could mean mistakenly hardened for
a fight that is not worth fighting for
or angry swords that are being
banged together and whipped around
in a dangerous way. The misterpered
weapons, although actual, could also
symbolize hate. 7 The penalty is
death. The fighters will be executed.
8 The Prince will talk to Capulet and
Montague separately. He will
apparently assess individual penalties
(“our farther pleasure”). Capulet will
meet with the Prince first; Montague
will meet with him later in the day.
L essons 41–60
still look and smell like itself. She
realizes that if Romeo had a different
name, he would still be himself.
Therefore, his name, his family, is not
important.
LESSON 59
Romeo and Juliet
Discussion Questions 1 east, sun.
The sun outshines the moon.
2 Romeo’s allusion to Diana suggests
that Juliet is even more beautiful than
a goddess. 3 Answers will vary. After
Romeo speaks line 9, an actress could
sigh or open her mouth as if she were
going to speak. 4 Two stars ask
Juliet’s eyes if they will take their
place in heaven for a while.
5 Juliet’s cheeks would outshine her
eyes. The simile is: “The brightness of
her cheek would shame those stars, /
As daylight doth a lamp.”
6 If Juliet’s eyes were in the sky, the
night time birds would think day had
arrived and would start singing. 7 In
line 20, the hidden stage direction is
that Juliet will rest her face on her
hand. 8 Juliet is like an angel because
she is on her balcony above Romeo
just like angels step from cloud to
cloud as astonished humans watch
them with up-turned eyes. 9 Juliet is
asking why Romeo is a Montague, a
member of the family who is
considered an enemy to her family.
10 Juliet decides that a person’s name
is not essential to identity. If a rose
were called a daisy, the rose would
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Reading
Activities
Answer Keys
Lessons 41–60
Activity 9
ACTIVITY 10
Comparing and Contrasting Two Poems
The Roman Empire in The Time of Julius Caesar
(Reading Lesson 45)
(Reading Lesson 51)
Answers will vary. Suggestions follow.
Atmosphere 1 shocking and mysterious: after shot,
silence then reaction 2 suspenseful and mysterious: dark,
deep, cold; there’s a ghost
Observation: In the first poem, there’s a silent shock after an
event, then an uneasy reaction sets in. In the second poem,
legend has increased the mysteriousness of the setting over
time.
GAUL
ITALY
SPAIN
Imagery that Supports Atmosphere 1 broken vase;
broken jar 2 shadow, with a stoop and a swing; phantom,
with a stoop and swing
STI
CYPRUS
PAL
E
CRETE
NE
SICILY GREECE
Observation In the first poem, some of the imagery is
sharp and clear, just like the gunshot sounded. In the
second poem, the imagery has movement and rhythm, just
like the ghost who skates.
AFRICA
ACTIVITY 11
Ending of the Story 1 The reader doesn’t know who fired
the gun or at what or if there is danger. 2 The reader
doesn’t know if there really is a ghost or if the “haunting”
is just an owl.
Figurative Language in Julius Caesar
(Reading Lesson 52)
Observation The disturbing mystery in the first poem
occurs once, yet it seems to say something about the
danger that can intrude on peace even to the point of
possibly being life-threatening. In the second poem,
although there is the question of who or what is haunting
the lake, being fearful of a natural setting does not seem as
serious as the sound and effect of a gunshot.
The following are suggested answers.
Some suggestions for additional categories are: Use of
Sound Devices, Role of Nature, and Role of Humans.
C. Literal: In the coffin is Caesar’s corpse and someone
else’s heart. Figurative: I am feeling depressed about
Caesar’s death.
A. Literal: Take your ears off your head and hand them to
me. Figurative: Please listen to me.
B. Literal: In addition to a corpse, a person’s coffin is
crammed with all the good things they did in life.
Figurative: The good that a person does in life ends with
his death.
D. Literal: Place a mountain in my upper chest between
my heart and my tongue. Figurative: Keep me from saying
what I really feel.
E. Literal: The color on his lips sprouted wings and flew
away. Figurative: He turned pale.
F. Literal: Several guilty tongues were tied together.
Figurative: Because of their guilt, they couldn’t speak.
G. Literal: Brave people can put death in their mouths and
taste it once. Figurative: Brave people often die.
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R eading A ctivities A nswer K ey
L essons 41–60
ACTIVITY 12
ACTIVITY 14
The Danish Empire
The World of King Henry V
(Reading Lesson 53)
(Reading Lesson 55)
es
Tham
r
Rive
NORWAY
London
ENGLAND
Calais
Southampton
Agincourt
SWEDEN
SCOTLAND
Abbeville
English Channel
Amiens
Dieppe
DENMARK
IRELAND
Nesle
Harfleur
Helsingør
Sein
e Riv
Copenhagen
er
Paris
ENGLAND
FRANCE
ACTIVITY 13
ACTIVITY 15
Old, Middle, and Modern English
(Reading Lesson 54)
Following is a free translation of the passage. A series of
dependent clauses leads to the last line, which is an
independent clause. The student’s will differ.
The Lowlands, the Highlands, and the Islands
(Reading Lesson 56)
Orkney
Islands
When in April the sweet showers
eb
ri
de
s
Pierce the drought of March to the root,
H
And when every living thing is bathed in such liquid
N o r t h
S e a
Cawdor
Inverness
Through whose power the flower is born,
Glamis
SCOTLAND
And when the West Wind with his sweet breath
Edinburgh
Has given life in all the forests and pastures
To the tender crops, and when the young sun
Has run half its course (now that it’s April),
IRELAND
I r i s h
S e a
And the little birds make music
ENGLAND
That sleep all night with open eye
ACTIVITY 15
So Mother Nature pricks them in their hearts,
At that time, people want to go on pilgrimages.
Comic Relief in Shakespeare’s Romeo and Juliet
(Reading Lesson 58)
Profession
Servant’s Version
Correct Tool
Shoemaker
yard
last
Tailor
last
yard(stick)
Fisher
pencil
nets
Painter
nets
pencil
The servant knows that he needs help. He decides to find
someone (the learned) who can read the list for him.
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History &
Geography
Workbook
Answer Keys
Lessons 41–60
Activity 33
Activity 35
A Constitutional Issue
The Pacific States and Capitals
(Lesson 41–49)
(Lesson 50)
Answers will vary. Use the Rubric for Self-Assessment, p.
275, America, to evaluate the final written speech. Check
each stage of the student’s work. He should have a list of
sources, note cards, a sheet showing identification of his
possible solutions, a thesis statement, a rough draft, and a
final essay. Encourage him read his final draft aloud, just
as it would be read if he were in Congress.
Activity 34
The Mountain States and Capitals
(Lesson 45)
Activity 36
Taxes
(Lesson 51)
Possible Revenue Choices for the New Government
Income Source
Sell land or exchange
bonds for land west
of the Appalachians.
1, 6, 15
Disadvantages
7, 10, 12
Tax imports—all
manufactured goods.
2, 9
3, 5, 11, 13
Tax on all agricultural
products sold in the
United States.
8, 14
4, 11
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Advantages
History & Geography Workbook Answer Key
L essons 41–60
Activity 37
Answers will vary, but the remainder should be about the
presidential accomplishments of his life.
The Northwest Territory
John Adams 91
(Lesson 52)
Massachusetts John Adams 91 July 4, 1826 Braintree,
Massachusetts United First Parish Church, Quincy,
Massachusetts
1 Lake Erie to Erie Canal to the Hudson River
2 Mississippi River to Gulf of Mexico to Atlantic Ocean to
Chesapeake Bay to Potomac River 3 Illinois River to
Mississippi River 4 Lake Erie to Erie Canal to Hudson
River to Atlantic Ocean 5 Wabash River to Ohio River to
Mississippi River to Gulf of Mexico to Atlantic Ocean
6 Missouri River to Mississippi River to Gulf of Mexico to
Atlantic Ocean
Adams October 30, 1735 Braintree, Massachusetts John
Adams and Susanna Boylston. He was educated at
Harvard University. Abigail Smith Adams October 25,
1764 Massachusetts five Abigail, John, Susanna, Charles,
and Thomas Adams
Answers will vary, but the remainder should be about the
presidential accomplishments of his life.
Activity 39
Thomas Jefferson 83
The Physical Features of the East
Virginia Thomas Jefferson 83 July 4, 1826 Monticello,
Virginia his home in the family cemetery
(Lesson 55)
Jefferson April 23, 1743 Albemarle County, Virginia Jane
Randolph and Peter Jefferson He was educated at the
College of William and Mary. Martha Wayles Skelton
January 1, 1772 Virginia three Martha, Patsy, and Mary
Answers will vary, but the remainder should be about the
presidential accomplishments of his life.
Activity 41
The Louisiana Purchase
(Lesson 57)
The final photo-essay will vary. Look for the following:
1 a title 2 at least 12 photographs 3 Each photograph has
a brief caption or explanation. 4 The choice of
photographs that explains the title has a clear “theme.”
Activity 42
The Star-Spangled Banner
(Lesson 59)
Activity 40
Translations will vary.
Obituary for a President
(Lessons 56 and 58)
George Washington 67
Virginia George Washington 67 December 14, 1799
Mount Vernon, Virginia his home
Washington February 22, 1732 Westmorland County,
Virginia Augustine Washington and Mary Ball
Washington He was educated only until his 16th birthday.
Martha Dandridge Custis January 6, 1759 Virginia two
stepchildren John Parke Custis and Martha (“Patsy”)
Parke Custis
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Science
Textbook
Answer Keys
Lessons 41–60
© Pearson Prentice Hall
Earth’s Changing Surface
Page 46
Skills Lab
Rock Shake
Expected Outcome The pieces in
container D will show the greatest
change in mass because those pieces
were subjected to both chemical and
mechanical weathering (acid and
shaking). The pieces in container A
will show little or no change in mass
because they were subjected to neither
chemical nor mechanical weathering.
The pieces in container C will
probably show a greater change in
mass than the pieces in container B,
depending on the type of limestone.
Analyze and Conclude 1 The percent
change in mass of the pieces in each
container will vary significantly,
depending on the type of limestone
used, the original mass of the pieces,
the strength of the acid, and the
amount of shaking. The exact figures
are not important but how the figures
compare is important. 2 There
should be a change in the mass of the
pieces in containers B, C, and D.
There should be little or no change in
mass of the pieces in container A.
3 The pieces in container D should
show the greatest change in total mass
because they were subjected to both
acid and shaking. The pieces in
container A should show the least
change because they were not
subjected to acid or shaking.
4 Most students correctly predict that
the acid and shaking will cause the
greatest amount of weathering.
5 The mass of the pieces in container
D showed the greatest change because
those pieces were soaked in acid
overnight and shaken the next day.
6 Most students will suggest that the
acid was more responsible for
breaking down the limestone because
the change in mass of the pieces in
container C was greater than the
change in mass of the pieces in
container B. 7 Two variables were
tested in this experiment—the effect
of shaking and the effect of acid. The
two containers that were not shaken
differ only in the absence or presence
of acid, so this variable is tested
exclusively. Shaking the two
containers the same amount of time
allowed the acidity variable to be
tested with shaking. The shaking
variable is tested in water by the
water, no shaking and water, shaking
containers. The shaking variable is
tested in acid by the vinegar, no
shaking and vinegar, shaking
containers.
Extend Inquiry
Design an Experiment Encourage
students to continue testing limestone
or other types of rock. Granite, for
example, is more resistant to both
acid and shaking.
Section 2
How Soil Forms
Page 48
Target Reading Skill
As the student reads each passage that
contains a key term, remind him to
write a sentence in his own words.
Encourage him to write one or two
descriptive phrases to help him
remember the key term. Call on him
to share his definitions.
Discover Activity
Expected Outcome Recipes should
reflect a variety of different particles
in the soil, including rock fragments
and organic matter.
Think It Over Answers will vary. A
typical answer might suggest that soil
is a mixture of different particles,
including sand, clay, rock fragments,
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and material derived from living
things.
Page 49
Figure 6 Water and air
Page 50
Figure 8 The A horizon
Page 51
Try This Activity
Expected Outcome Students may
find rocks, sand, clay, silt, insects,
worms, and plants. The soil’s fertility
is based on its composition,
particularly the amount of humus.
Figure 9 Alaska
Reading Checkpoint forest, prairie,
desert, mountain, tundra, and tropical
Page 53
Figure 10 Earthworms and
burrowing animals
Page 54
Figure 11 The soil is likely to be very
fertile because earthworms carry
humus down to the subsoil and pass
out soil as waste, which is enriched
with substances plants need to grow.
Reading Checkpoint Earthworms
Reviewing Key Concepts
1 a Rock particles, minerals, decayed
organic material, air, and water b Soil
horizons form as bedrock weathers,
and rock breaks up into soil particles.
Plants weather rock mechanically and
chemically and add organic material
to the soil. Rainwater washes clay and
minerals from topsoil to other soil
horizons. c Topsoil, subsoil, C
horizon, bedrock 2 a Climate, plants,
and soil composition b Tundra soils
and desert soils would form most
slowly. Tundras are cold, and deserts
are dry. 3 a Some soil organisms
make humus, a material that makes
S cience T extbook A nswer K ey
soil fertile. Other soil organisms mix
the soil and make spaces for air and
water. b Decomposers include fungi,
bacteria, and worms. They digest or
decompose dead organic material and
mix it with the soil. c The soil would
become less fertile because the
decomposers make humus.
Writing in Science
Writing Skill Persuasion
Scoring Rubric: 4 Exceeds criteria in
some way; for example, by reading
and appearing like an actual product
label 3 Meets criteria but does not go
beyond requirements 2 Includes only
brief description of required elements
1 Is incorrect and incomplete
Page 55
Consumer Lab
Comparing Soils
Expected Outcome Specific outcomes
will depend on the soil samples used.
Student should be able to observe
various characteristics of his sample.
Analyze and Conclude 1 Answers
will vary, depending on the local soil
samples used. Most bagged topsoil
samples will have high percentages of
organic materials. Most natural soils
will have less organic material.
2 Student should be able to estimate
what proportions of the sample are
clay, silt, and sand. Organic material
will float in water. 3 Student might
note that the bagged topsoil contains
more organic matter and was formed
from more plant matter than the local
soil. 4 Hypotheses will vary depending
on the soil samples. Normally, bagged
topsoil is a good mix for flowers and
vegetables. 5 Reports will vary.
Student’s suggestions should be
supported by data.
Extend Inquiry
Design an Experiment Student’s
experiments should have the two
different soil samples as the
independent variable. The factors to
control include the amount of
sunlight, the amount of water, and the
temperature. Student should develop
L essons 41–60
a procedure, a list of materials, and a
method of recording data.
Section 3
Soil Conservation
Page 56
Target Reading Skill
Possible answers: Where was the Dust
Bowl? (The Dust Bowl was in western
Oklahoma and parts of the
surrounding states.) What caused the
Dust Bowl? (Farming practices
exposed the soil so that in times of
drought the topsoil quickly dried out,
turned to dust, and blew away.)
Discover Activity
Expected Outcome Student will
discover a variety of ways to prevent
the soil from washing away.
Think It Over Answers will vary.
Typical answers might suggest ways
that protect the soil or bind it
together.
Page 57
Figure 12 Nitrogen
Reading Checkpoint Fertile soil is
valuable because there is only a
limited supply of it.
Page 58
Reading Checkpoint A combination
of overplowing and drought
Page 59
Figure 14 It prevents excess rainfall
from washing the soil away.
Reading Checkpoint It disturbs the
soil as little as possible, leaving plants
in the ground to retain nutrients and
moisture to prevent erosion.
Reviewing Key Concepts
1 a Anything in the environment that
humans use b All living organisms
depend, either directly or indirectly,
on soil to live and grow. 2 a Loss of
fertility and loss of topsoil b Topsoil
is lost because of erosion by wind and
water. c A combination of
overplowing and drought turned the
soil in the Great Plains to dust.
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3 a The management of soil to
prevent its destruction b Contour
plowing, conservation plowing, and
crop rotation c A combination of
conservation plowing to reduce
erosion and crop rotation to maintain
soil fertility
Writing in Science
Writing Skill Persuasion
Scoring Rubric: 4 Exceeds criteria in
some way; for example, by referencing
the Dust Bowl of the 1930s 3 Meets
criteria but does not go beyond
requirements 2 Includes only brief
description of required elements
1 Is incorrect and incomplete
Page 61
Review and Assessment
Organizing Information a The C
horizon forms as bedrock breaks
apart. b The A horizon develops from
the C horizon when plants grow in it.
c The B horizon develops as clay and
minerals wash down from the A
horizon.
Reviewing Key Terms 1 c 2 a 3 b
4 a 5 d 6 erosion 7 true 8 humus
9 true 10 conservation plowing
Writing in Science
Writing Skill Description
Scoring Rubric: 4 Exceeds criteria in
some way; for example, by including
methods the farmer might use to
preserve topsoil 3 Meets criteria but
does not go beyond requirements
2 Includes only brief description of
required elements 1 Is incorrect and
incomplete
Page 62
Checking Concepts 11 The principle
of uniformitarianism states that the
same processes that operate today
operated in the past. 12 Plants are an
agent of mechanical weathering when
their roots pry open cracks in rock.
Plants are an agent of chemical
weathering when their roots produce
weak acids that slowly dissolve rock.
13 Oxygen combines with iron in a
process called oxidation, which results
S cience T extbook A nswer K ey
in rust. Carbon dioxide dissolves in
water to form carbonic acid, which
weathers rock. 14 Soil forms as rock
is broken down by weathering and
mixes with other materials on the
surface. 15 Topsoil contains more
humus than subsoil. Because topsoil
contains more humus, it is more
fertile than subsoil. 16 Earthworms
do most of the work of mixing humus
into soil. 17 Grass held the soil in
place and provided organic matter to
the soil. 18 Conservation plowing
disturbs the soil and plant cover as
little as possible, thus keeping soil in
place, retaining moisture, and
conserving soil nutrients. When using
crop rotation, the farmer plants
different crops each year at the same
location, allowing crops to
periodically restore nutrients that
have been lost.
Thinking Critically 19 Breaking a
rock into pieces increases the rate at
which the rock will weather
chemically because the broken rock
has more surface area exposed to
weathering agents. 20 a The A
horizon contains highly weathered
rock and mineral pieces and abundant
humus from the decay of organic
remains. b The B horizon is less
weathered and contains less humus
than the A horizon does. It is enriched
in clay and some other minerals that
were washed down from the A
horizon. c The C horizon is the least
weathered horizon. It is similar to
bedrock. 21 Mechanical; chemical;
chemical
Applying Skills 22 The sandy soil
would lose water more quickly
because water can move through the
spaces between grains easily. Clay
particles hold water better.
23 Answers will vary. A typical design
could include the following: use two
identical flowerpots with drain holes;
place gravel at the bottom of each pot,
and cover with equal amounts of the
sample soils; suspend the pots over
two catch basins, and pour equal
amounts of water into the pots.
L essons 41–60
Compare how quickly water passes
through the pots. 24 Answers will
vary. Sample questions: In what kind
of soil do soybeans grow best? What
needs to be added to either type of soil
to make it suitable for growing
soybeans?
Page 63
Standardized Test Prep
1 D 2 H 3 D 4 J 5 A 6 The rates
of chemical weathering, mechanical
weathering, or both might have been
faster where the mature soil formed.
These differences could be due to
climate or vegetation differences. Tree
roots might have increased
mechanical weathering. High
temperature and moisture might have
increased acid weathering and
oxidation. Also, the type of rock in the
area with immature soil might have
been more resistant to weathering
than the other type of rock.
Chapter 3
Section 1
Changing Earth’s Surface
Page 66
Target Reading Skill
One way that students might organize
the information is as follows.
Landslide: rapid, steep; Mudflow:
rapid, gentle to steep; Slump: rapid,
steep; Creep: slow, gentle to steep
Discover Activity
Expected Outcome Upon tipping the
board, the marble will immediately
roll down the slope, but the block of
wood will slide down only when the
board is tipped higher. When the
block of wood and board are covered
with sandpaper, the block will not
move unless the board is tipped up
almost to vertical.
Think It Over Hypotheses will vary.
A typical hypothesis might suggest
that downward movement depends on
the slope angle and on the frictional
resistance.
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Page 67
Figure 2 The land surface would
become flat and featureless.
Reading Checkpoint Loose pieces of
rock, soil, or animal and plant
remains that can be moved by erosion
Skills Activity
Expected Outcome Student models
and outcomes will vary. Student might
suggest improvements that include
changing the slope angle, sediment
size, or amount of water.
Page 68
Figure 3 Landslide
Page 69
Reading Checkpoint The main
difference between slump and
landslide is that the material in a
slump moves as one large mass.
Reviewing Key Concepts 1 a Five
agents of erosion are gravity, running
water, glaciers, waves, and wind.
b Deposition is a process that occurs
when agents of erosion lay down
sediment, which changes the shape
of the land. c Erosion will gradually
wear away the mountain range.
Deposition will fill valleys with
sediment. 2 a Four types of mass
movement are landslide, mudflow,
slump, and creep. b Gravity causes
all types of mass movement. c The
fence moved as a result of creep.
At-Home Activity
Evidence of Erosion Encourage
student to make his erosion survey
around his neighborhood. Advise him
to look for evidence of sediment that
has moved downhill because of
gravity. Student can bring his
drawings or photos and share
interesting examples.
Page 70
Skills Lab
Sand Hills
Expected Outcome Both the height
and the width of the sand hill increase
as more sand is added. Repeated
S cience T extbook A nswer K ey
L essons 41–60
tests show that the ratio between the
sand hill’s width and height remains
constant (that is, the points form
approximately a straight line on
the graph). The value of this ratio
can vary. It depends mostly on the
characteristics of the sand grains (size,
shape) and the amount of moisture in
the sand.
Analyze and Conclude 1 A typical
graph should show a line rising from
left to right. If height is on the x-axis
and width on the y-axis, the slope of
the line should be about 3. However,
this value can vary slightly. 2 The
ratio between height and width
remains the same. 3 Answers will
vary, depending on student’s
hypotheses. Student should compare
his original hypothesis with the data
he collected. 4 Advise student who
proposed a hypothesis that was not
supported to develop a new
hypothesis that is consistent with the
data collected. 5 Student extends the
line on the graph with a dashed line to
indicate that the ratio between width
and height will continue to remain the
same. Student could test this
prediction by trying to form sand hills
of appropriate size. 6 Student’s
answers will vary. Student might
mention that disturbing the sand hills
while taking measurements affected
results.
Discover Activity
Expected Outcome The dripping
water will wear a depression in the bar
of soap.
Extend Inquiry
Design an Experiment Hypotheses
will vary. Using wet sand will produce
hills that stand at a higher angle
(lower width-to-height ratio). Using
larger sediment, such as gravel, also
will produce hills that stand at a
higher angle.
Page 76
Section 2
Water Erosion
Page 72
Target Reading Skill
Q What features does a river produce
by erosion? A V-shaped valley, bluffs
Q What feature does a river produce
by deposition? A Delta
Think It Over Predictions will vary.
Typical predictions might suggest that
the depression would be larger after
another 10 minutes and larger still
after an hour. Increasing the flow
would speed up the process; decreasing
the flow would slow it down.
Page 73
Figure 4 Less than 0.25 cm
Page 74
Try This Activity
Expected Outcome The drops from
2 m will cause splashes that travel
farther than the splashes from the
1-m drops. Because the drops move
sediment when they hit the soil, the
2-m drops will cause more erosion.
The 2-m drops have more kinetic
energy because the water falls from
a greater distance.
Page 75
Figure 5 The land between the gullies
will become narrower as the sides of
the gullies erode.
Reading Checkpoint A stream or
river that flows into a larger river
Reading Checkpoint An oxbow lake
forms when a meander is cut off from
the river.
Page 77
Figure 9 The water in the river slows
down and deposits sediment in the
delta. The river’s main channel flows
almost to the tip of the delta, where it
divides into several channels to form
the “bird foot.”
Reading Checkpoint The sediment
that is deposited by a flood becomes
fertile soil.
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Page 79
Figure 10 Erosion: waterfalls,
V-shaped valleys, flood plain,
meanders, oxbow lake, bluffs;
Deposition: beaches, delta Note: An
oxbow lake involves both processes
but is classified under erosion in
this text.
Page 80
Reading Checkpoint Water that
contains calcium and carbonic acid
drips into a cave. When carbon
dioxide leaves the solution, a deposit
of calcite is left behind.
Page 81
Figure 12 The cave’s roof will
collapse to form a sinkhole.
Reviewing Key Concepts
1 a Moving water b Runoff, rill,
gully, stream, tributary, river
c A field with plowed soil and no
plants—there would not be anything
to hold the soil in place. 2 a Valleys,
waterfalls, flood plains, meanders, and
oxbow lakes b Alluvial fans, river
deltas, and soil on flood plains c The
flowing water of the river slows down
and deposits its sediment.
3 a Chemical weathering b Carbonic
acid in groundwater breaks down
limestone, which is carried away in
solution by the water. Eventually a cave
forms. If the level of groundwater
lowers, the cave becomes filled with air.
Stalactites and stalagmites can form
when water that contains carbonic acid
and calcium drips into the cave.
At-Home Activity
Erosion Cube Students will find that
some of the sugar of the large cube
dissolves in water from the paper
towel, which leaves the cube smaller
and misshapen. The purpose of
building a large cube with smaller
ones is to form cracks for water to
seep through. This is analogous to
water seeping through cracks in
limestone, eroding the rock, and then
carrying the material away in solution.
S cience T extbook A nswer K ey
Page 82
Skills Lab
Streams in Action
Expected Outcome In Part 1, the
water erodes the diatomaceous earth.
The dripped water will form a
channel; the 10-minute drip will cause
a deeper channel than the 5-minute
drip. In Part 2, increasing the angle of
slope will produce a deeper channel
and cause more erosion.
Analyze and Conclude 1 The
10-minute stream should have a
deeper channel than the 5-minute
stream. The longer the water flowed,
the more erosion occurred along the
stream bed. 2 Most students will have
predicted that increasing the angle of
slope would result in a deeper channel
and more erosion; the student’s
results should confirm this prediction.
3 The eroded material moved down
the slope until it was deposited.
4 Student observed a channel that is
more deeply incised at its head. Other
features, such as meanders, might
have been observed away from the
stream’s head. Student might suggest
that allowing the drip to continue for
a longer time will allow more features
to develop. 5 The characteristics of
the sediment or bedrock, the amount
and type of vegetation, the frequency
and intensity of floods 6 Answers will
vary. Make certain student includes
details about the erosion event he
describes.
Extend Inquiry
Design an Experiment Designs will
vary. Student might suggest dripping
water onto opposite sides of the slope
at two different rates and measuring
the erosion caused by each stream.
After reviewing the design, encourage
student to conduct his experiment.
Section 3
The Force of Moving Water
Page 86
Target Reading Skill
As student reads each passage that
contains a key term, remind him to
write a sentence in his own words.
L essons 41–60
Encourage him to write one or two
descriptive phrases to help him
remember the key term. Ask him to
share his definitions.
Discover Activity
Expected Outcome Student will
observe the settling of the sediments.
The larger particles will settle first, and
the smaller grains will settle last. After
10 to 15 minutes, most of the particles
will have settled, but the water will
remain cloudy because of the continued
suspension of fine clay particles.
Think It Over The particles are
deposited according to size. Gravity
acting on the different sizes of grains
causes the pattern.
Page 87
Figure 14 A boulder would likely roll
or slide downstream.
Reading Checkpoint Gravity and the
force of the moving water
Skills Activity
Expected Outcome A typical
hypothesis might suggest that the
river that produced the gravel-boulder
alluvial fan had a greater slope and
volume of flow than the river that
produced the sand-silt fan.
Extend Challenge student to design
an experiment to test his hypothesis
using a stream table.
Page 88
Figure 15 At the highest point
Page 89
Math Analyzing Data 1 Stream
velocity 2 Diameter of sediment
particles 3 About 50 cm/sec; about 90
cm/sec; about 800 cm/sec 4 Small
boulders 5 Possible answer: The
faster the speed of the flowing water,
the larger the particles the stream is
able to move.
Page 90
Figure 17 The water speed is slowest
there.
Reading Checkpoint On the outside
of the curve
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Reviewing Key Concepts
1 a The ability to do work or to cause
change b Gravity causes river water
to move down a slope. As the water
flows, its potential energy changes
into kinetic energy. c Erosion and
deposition 2 a Mass movement and
runoff b Sand and other sediment
grains can strike the rock of the
stream’s bed and wear it away. This
process is called abrasion. c The piece
of rock will become smaller and more
rounded as it bounces or rolls along
the stream bed. This occurs because
pieces get broken off the rock. Jagged
corners are more easily broken, so the
rock becomes rounded. 3 a Slope,
volume of flow, and shape of the
stream bed b The river’s bank will
eventually erode, and the curve will
become larger.
Writing in Science
Writing Mode Description
Scoring Rubric: 4 Exceeds criteria in
some way, for example, explaining
how the particles cause erosion of the
stream bed 3 Meets criteria but does
not go beyond requirements
2 Includes only brief description of
required elements 1 Is incorrect and
incomplete
Section 4
Glaciers
Page 91
Target Reading Skill
Q What kinds of glaciers are there?
A Valley glaciers and continental
glaciers Q How do glaciers shape the
land? A By erosion and deposition
Discover Activity
Expected Outcome The sand should
have frozen into the bottom of the ice.
Rubbing the sand side of the ice block
over soap will produce grooves and
striations.
Think It Over Answers will vary. A
typical answer might suggest that the
sediment in ice changes the land by
scratching and scraping the
underlying rock.
S cience T extbook A nswer K ey
Page 93
Figure 19 Sharp ridges called arêtes
and valleys that hang above a lower
valley
Reading Checkpoint Mountain
valleys that were formed originally
by rivers
Page 95
Figure 20 Drumlin, deposition; horn,
erosion; cirque, erosion; moraine,
deposition; U-shaped valley, erosion
Reading Checkpoint A terminal
moraine is a ridge of till deposited at
the farthest point reached by a glacier.
Reviewing Key Concepts
1 a A continental glacier is a glacier
that covers much of a continent or
large island. b A valley glacier is a
long, narrow glacier in a mountain
valley. c Both types of glaciers are
large masses of ice that move over
land. Valley glaciers are long and
narrow—the sides of the valley keep
them from spreading. Continental
glaciers spread out over a large area
of land. 2 a Glaciers form in areas
where more snow falls than melts.
b Glaciers flow downhill because of
the force of gravity. c Snow changes
to ice as it is compacted by overlying
snow. 3 a Plucking and abrasion
b Deposition occurs when the glacier
melts and leaves rock and sediment
on the land.
Writing in Science
Writing Mode Persuasion
Scoring Rubric: 4 Exceeds criteria in
some way, for example, using vivid
descriptions and engaging the reader
3 Meets criteria but does not go
beyond requirements 2 Includes only
brief description of required elements
1 Is incorrect and incomplete
Page 96
Target Reading Skill
Detail: Energy in waves breaks apart
rocks. Detail: Sediment wears away
rock. Detail: Landforms are created.
L essons 41–60
Discover Activity
Expected Outcome Student probably
will observe differences between the
two samples. Differences might include
grain shape, size, or color.
Think It Over Questions will vary.
Possible questions: Is beach sand a
result of erosion? How is beach sand
deposited? What causes differences in
beach sand at different places?
Page 97
Figure 21 The headlands will erode,
and the shoreline will be straighter.
Page 99
Figure 22 The sea arch eventually will
collapse because of continued erosion.
Reading Checkpoint Waves erode
the base of a rocky cliff, causing sea
caves or a collapse of the upper
portion of the cliff.
Skills Activity
Expected Outcome The student will
set up and solve an equation to find
the total erosion. Total Erosion =
(1.25 m/y) (50 y) + (3.75 m/storm)
(12 storms) = 107.5 meters
Page 100
Figure 23 Two
Reading Checkpoint Barrier beaches
form when storm waves pile sand
above sea level.
Writing in Science
Writing Mode Exposition Cause and
Effect
Scoring Rubric: 4 Exceeds criteria in
some way, for example, explaining the
risk of building a home on a barrier
beach 3 Meets criteria but does not
go beyond requirements 2 Includes
only brief description of required
elements 1 Is incorrect and
incomplete
through the air. Medium-sized
particles skip and bounce. Larger
particles slide or roll.
Discover Activity
Think It Over Student will observe
that blowing gently through the straw
eroded cornmeal from some places.
Page 103
Figure 24 In both processes, larger
grains slide or roll, and smaller grains
are carried in suspension. One major
difference is that water carries some
dissolved material.
Reading Checkpoint Wind erosion
often is evident in areas where there
are few plants to hold soil in place.
Reviewing Key Concepts
1 a Deflation and abrasion b Fine
particles are carried through air,
medium-sized particles skip or
bounce, and heavier particles slide or
roll. c The sand would erode much
more than the rocks, so the land
surface eventually would be mostly
rocks. 2 a Sediment is deposited
when wind slows down or blows
around an obstacle. b Sand dunes
and loess deposits c Plants, such as
grass, could be planted on the dunes,
or a fence might be placed at the edge
of the dunes.
At-Home Activity
Desert Pavement Caution student to
make sure family members are far
enough away to avoid getting flour in
their eyes. Student should be prepared
to explain what deflation is and what
the coins and flour represent.
Page 105
Review and Assessment
Organizing Information a Rills form
b Gullies form c Gullies join together
d Stream forms
Reviewing Key Terms 1 c 2 a 3 b
4 b 5 b 6 deposition 7 Runoff
8 true 9 true 10 moraine
Section 6
Wind
Page 101
Target Reading Skill
Wind picks up smallest particles of
sediment. Fine particles are carried
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Writing in Science
Writing Mode Description
S cience T extbook A nswer K ey
Scoring Rubric: 4 Exceeds criteria
in some way, for example, uses vivid
adjectives and gives a personalized
account 3 Meets criteria but does not
go beyond requirements 2 Includes
only brief description of required
elements 1 Is incorrect and
incomplete
Page 106
Checking Concepts 11 The agents of
erosion that are assisted by the force
of gravity are moving water and
glaciers. Gravity itself causes mass
movement and is therefore also an
agent of erosion. 12 In general,
higher slope and higher volume of
flow increase a river’s sediment load.
13 Turbulence is rough-flowing
water. It slows the speed of a river but
often increases its power to erode.
14 The speed of the flowing water in
a river is the slowest near the bottom,
where friction is greatest. 15 Ice ages
are times when glaciers cover large
parts of Earth’s surface. 16 Kettle
lakes form when a large piece of
glacial ice is left in a glacial deposit.
When the ice melts, a depression
forms and fills with water. 17 Loess
deposits form as fine particles that are
carried by wind fall to the ground and
accumulate.
Thinking Critically 18 Both are
types of mass movement that occur
rapidly and can be triggered by an
earthquake. Unlike landslides, which
are mostly dry, mudflows have a high
percentage of water. 19 Abrasion
occurs when particles of sediment in
flowing water bump into the stream
bed again and again. A very turbulent
stream or the fast-flowing water of a
flooding river would cause the most
abrasion. 20 A house right on a
riverbank is probably within the
river’s flood plain. A family should
hesitate because the house might be
damaged or destroyed by a future
flood. 21 a A sinkhole forms when
the roof of a cave collapses.
b Stalactites form as calcium
carbonate precipitates from water
dripping from the ceiling.
L essons 41–60
c Stalagmites form as calcium
carbonate precipitates from drops that
fall to the cave floor. 22 Answers will
vary. Possible answer: You could
observe the landforms in front of the
glacier. If it is retreating, terminal
moraines and other till deposits
should exist far in front of the glacier.
23 The sand came from rivers that
carried the grains to the ocean, where
waves dropped them to form the
beach.
Applying Skills 24 The flow and load
were greatest in April. They were
lowest in January. 25 A river’s load
varies directly with its volume of flow.
26 Rainfall or melting snow probably
increased throughout the drainage
basin in April, creating more runoff
and eroding more sediment.
What You Learned 1 Molds and
casts are types of fossils. 2 Organisms
are also preserved in amber, tar, and
ice. 3 Fossils tell us about past
climates, changes in Earth’s surface,
and how organisms have changed
over time.
Discover Activity
Think It Over The rock contains one
or more fossils. A typical explanation
of how the fossils formed might
suggest that an organism fell into
sediments that later solidified.
Page 111
Figure 1 Sedimentary rock
Page 112
Figure 2 Mold
Page 113
Page 107
Standardized Test Prep
1 C 2 J 3 A 4 F 5 A 6 Erosion is
the picking up and moving of rock,
sediment, or soil. Gravity causes
erosion by mass movement, running
water, and glaciers. During mass
movement, gravity pulls rock or
sediment downhill. Running water
moves downhill because of the force
of gravity. As the water flows, it
erodes Earth’s surface. Gravity also
causes glacier ice to flow. The flowing
ice erodes rock and sediment from
some places and deposits rock and
sediment at other places.
Chapter 4
Section 1
Fossils
Reading Checkpoint Remains can be
trapped in tar, amber, or ice.
Try This Activity
Expected Outcome The sugar cube
entirely wrapped in clay is preserved,
and the other sugar cube dissolves
into the water. The activity models
how mud or other sediment can
prevent the decay of an organism by
protecting it from exposure to water.
Page 115
Figure 3 The bat’s body may have
fallen into the mud when the bat died.
Accept all reasonable responses.
Page 116
Figure 4 It is an extinct animal.
Reading Checkpoint A well-tested
concept that explains a wide range of
observations
Page 110
Target Reading Skill
Possible answers:
What You Know 1 Fossils come
from ancient organisms. 2 Fossils are
found in hardened rock. 3 Fossils
show us how some present-day
organisms looked different in the past.
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Reviewing Key Concepts
1 a The preserved remains or traces of
a living thing b Most fossils are
formed when living things die and are
buried by sediments. The sediments
slowly harden into rock and preserve
the shapes of the organisms. c Hard
parts of an organism usually form
fossils because they are less likely to
be lost by decay. 2 a Petrified fossils,
S cience T extbook A nswer K ey
L essons 41–60
molds, casts, carbon films, and trace
fossils b When an organism is buried
by sediment, gases from the organism
evaporate, leaving behind a thin film
of carbon that preserves parts of the
organism. c They are similar because
the remains of both are not destroyed
by decay. They are different because
preserved remains are the actual
organism, whereas the soft parts of
petrified organisms are replaced by
minerals. 3 a Past environments and
how groups of organisms have
changed over time b Life on Earth
has evolved, or changed over time.
Simple organisms have given rise to
more complex plants and animals.
Think It Over The oldest layer is
found on the outside ring, touching
the bowl.
At-Home Activity
Family Fossils Encourage student to
ask older members of his family to
find something that has been passed
down from generation to generation.
Suggest that he write down why the
object was preserved to help him
remember in telling the story.
Page 120
Section 2
The Relative Age of Rocks
Page 121
Page 117
Reviewing Key Concepts
1 a Relative age states whether a rock
is younger or older than another rock.
Absolute age is a rock’s age in years.
b In horizontal layers of sedimentary
rock, the oldest layer is at the bottom,
and each higher layer is younger than
the layer below it. c The bottom; it
was the first to be formed by deposits.
2 a Igneous rock intrusions and
extrusions, faults, and unconformities
b Both form from molten material.
Lava that hardens on the surface is an
extrusion. Magma that cools below
the surface is an intrusion. c The
extrusion; intrusions are always
younger than the rock layers through
which they pass. 3 a A fossil that is
used to determine the relative age of
rocks b No. They have existed with
little change for a long time.
Target Reading Skill
Possible questions and answers: What
does the position of rock layers reveal?
(The oldest layers—and the oldest
fossils—are at the bottom.) How do
geologists determine the relative age
of a rock? (The position of rock layers,
extrusions and intrusions of igneous
rock, faults, and gaps in the geologic
record) How are fossils used to date
rocks? (The age of an index fossil tells
the age of the rock layer in which it
occurs.)
Discover Activity
Expected Outcome The oldest layer
is the bottom layer when the layers are
flat. When the layers are pressed over
the bowl and the top of the dome is
cut off, the oldest layer is in the center
of the dome, even if it rises above the
other layers.
Page 119
Figure 5 The Supai Sandstone; the
oldest layer is at the bottom.
Reading Checkpoint The sediment
that forms sedimentary rocks is
deposited in flat layers one on top of
the other.
Try This Activity
Expected Outcome The oldest is the
bottom; the youngest is the top. Core
samples provide information about
layers of rock.
Figure 7 Erosion and deposition
Reading Checkpoint A gap in the
geological record
Reading Checkpoint It must be
widely distributed, and it must have
existed for only a brief period of time.
Figure 8 The trilobites in Layer A
At-Home Activity
Drawer to the Past Encourage student
to carry out the activity. Clues used to
determine relative ages might include
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the memories of family members and
the condition of an item. Some items,
such as coins, may contain dates that
indicate an absolute age.
Page 122
Skills Lab
Finding Clues to Rock Layers
Analyze and Conclude 1 Fossils of
marine animals in layers A and B
indicate a marine environment.
Dinosaur tracks and a leaf suggest that
a land environment created layer D.
2 According to the law of
superposition, layer A is the oldest
because it is below all other layers.
3 According to the law of
superposition, layer G formed most
recently because it is above all other
layers. 4 Layers C and E are
extrusions of igneous rock, in which
fossils can’t form. 5 Dinosaur, plant,
and bird fossils 6 Layer B 7 Rock
layers that are missing from the
sequence at Site 2 provide clues of an
unconformity. Layers E and D are
missing between layers X and Y,
which suggests that the boundary
between Y and X is an unconformity.
Layer A is also missing, which
suggests that there is an unconformity
below W. 8 Layer Y is older because
an intrusion is always younger than
the layer through which it passes.
9 The environment most likely started
out as an ocean environment.
Volcanic extrusions covered the
environment over many years,
eventually creating a swamplike
environment in which dinosaurs lived.
Extend Inquiry
More to Explore Because faults can
occur only after rock layers have
formed, any layers the fault cuts
across would be older than the fault.
Section 3
Radioactive Dating
Page 123
Target Reading Skill
Possible answers: Main Idea: Using
radioactive dating, scientists can
S cience T extbook A nswer K ey
determine . . .; Detail: the absolute ages
of the most ancient rocks using
potassium-40; Detail: the absolute ages
of fossils using carbon-14 up to about
50,000 years ago; Detail: the ages of
sedimentary rocks by dating the
igneous intrusions and extrusions near
the sedimentary rock.
Discover Activity
Expected Outcome By cutting the
clay in half three times, student will
reduce the size of the cube to oneeighth the original size.
Think It Over The remaining piece
will be very small, possibly too small
to cut in half again with the knife.
Page 124
Figure 11 12.5% or 1/8
Reading Checkpoint The time it
takes for half of the radioactive atoms
in an element to decay
Page 125
Math Skills 3.125%
Page 126
Section 4
The Geologic Time Scale
Page 127
Target Reading Skill
The flowchart will be filled in as
follows: Geologic Time Scale
Precambrian Time; Paleozoic Era:
Cambrian Period; Paleozoic Era:
Ordovician Period; Paleozoic Era:
Silurian; Paleozoic Era: Devonian;
Paleozoic Era: Carboniferous;
Paleozoic Era: Permian; Mesozoic Era:
Triassic; Mesozoic Era: Jurassic;
Mesozoic Era: Cretaceous; Cenozoic
Era: Tertiary; Cenozoic Era:
Quaternary
Discover Activity
Expected Outcome Student will place
ten or more events along the timeline.
Think It Over If student follows the
suggested divisions, the most
important events of his life will
probably fall within the middle school
years because he can more easily
remember recent events than events
earlier in life.
Figure 13 The shale is younger than
the extrusion but older than the
intrusion.
Page 128
Reading Checkpoint Potassiumargon dating and carbon-14 dating
Page 129
Reviewing Key Concepts
1 a Possible answer: The process in
which an element changes to another
element because the atoms break
down b The amount of the
radioactive element decreases. The
amount of the new element increases.
c The rate of decay is constant—it
never changes. 2 a Radioactive dating
b The particles in sedimentary rocks
are made up of different substances of
different ages. c The scientist could
use radioactive dating to find the ages
of the two igneous extrusions. The age
of the sedimentary rock would be
somewhere in between the two ages.
Math Practice 3 0.78125%
L essons 41–60
Figure 14 245 million years ago
Reading Checkpoint Mesozoic
Reviewing Key Concepts
1 a A record of the life forms and
geological events in Earth’s history
b Scientists studied rock layers and
fossils worldwide and placed Earth’s
rock layers in order by relative age.
Later, radioactive dating helped them
determine the absolute ages of the
divisions. 2 a Eras and periods
b Precambrian Time; 4.6 billion years
ago; 544 million years ago
c Triassic, Jurassic, Cretaceous,
Tertiary, Quaternary
Writing in Science
Writing Skill Description
Scoring rubric: 4 Exceeds criteria,
includes its length, the era to which it
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belongs, the names of the periods
before and after it, and its position
relative to the present 3 Meets criteria
except position relative to the present
2 Includes two of the three criteria
1 Includes only one criterion or
inaccurate information
Section 5
Early Earth
Page 130
Target Reading Skill
Possible answers: Early Earth:
Atmosphere—Hydrogen and helium
Oceans—Earth’s surface is too hot.
All water evaporates into water vapor.
Continents—Less dense rock at
surface forms continents. Later
Precambrian Earth: Atmosphere—
Carbon dioxide, nitrogen, and water
vapor Oceans—Earth cools, water
vapor condenses, and rain falls. Rain
forms oceans. Continents—Old
continents break apart and new
continents form as a result of
continental drift.
Discover Activity
Expected Outcome The iron filings
will gather around the poles of the
magnet.
Think It Over The iron filings would
continue to gather in clumps around
the magnet. The model shows how
early materials in space were gathered
in a ball by the force of gravity to
form Earth. In the magnet model, the
force is the attraction of iron to the
poles of the magnet.
Page 131
Reading Checkpoint Gravity
Page 132
Skills Activity
Expected Outcome Precambrian
Time lasted for 86% of Earth’s history.
About 11% of Precambrian Time
elapsed before the development of the
continents.
S cience T extbook A nswer K ey
Figure 17 The first atmosphere
contained hydrogen and helium. The
second atmosphere contained
nitrogen, oxygen, carbon dioxide,
water vapor, and argon.
Reading Checkpoint The process by
which the continents move very
slowly over Earth’s surface because of
forces inside Earth
Page 133
Reviewing Key Concepts
1 a About 4.6 billion years ago
b Radioactive dating of rocks from
Earth and the moon 2 a Oceans, the
atmosphere, and continents
b They released carbon dioxide and
water vapor into the atmosphere.
c Rain 3 a Bacteria-like organisms
b It would have little or no oxygen.
Writing in Science
Writing Mode Description
Scoring rubric: 4 Exceeds criteria;
plan includes information about early
Earth’s atmosphere, oceans,
continents, and life forms; sketches
and descriptions are accurate and
informative 3 Meets criteria but
sketches and descriptions are not
imaginative 2 Includes only some
criteria 1 Is inaccurate and incomplete
L essons 41–60
student will probably not be able to
identify.
Think It Over Student’s questions
will vary. Typical questions: When did
each of these organisms live? In what
type of environment did these
organisms live? What organisms ate
these organisms?
Page 136
Figure 21 Amphibians, reptiles,
insects, ferns, and cone-bearing
plants.
Page 137
Math Analyzing Data 1 The x-axis
shows time in millions of years before
the present; the y-axis shows the
number of families of ocean animals
2 Slightly more than 50 million years
ago 3 The one that occurred about
230 million years ago 4 The number
of families of ocean animals
immediately dropped but then
increased.
Reading Checkpoint A
supercontinent formed when Earth’s
continents moved together about 260
million years ago.
Page 143
Figure 23 It has claws on its wings.
Section 6
Eras of Earth’s History
Reading Checkpoint Dinosaurs,
mammals, birds, and flowering plants
Page 134
Page 144
Target Reading Skill
Possible questions and answers: What
geologic events happened during
Precambrian Time? (Earth, the
oceans, and the first sedimentary
rocks formed.) When did dinosaurs
appear on Earth? (About 225 million
years ago.) What caused the mass
extinction at the end of the
Cretaceous Period? (An object from
space struck Earth and blocked the
sunlight.)
Lab Zone
Discover Activity
Expected Outcome Each fossil is an
impression or carbon film. Fossil A is
a leaf. Fossil B is a eurypterid, which
Try This Activity
Expected Outcome Order of events:
oldest fossils form, 3.5 billion years
ago; “explosion” of invertebrates
occurs, 544 million years ago; first fish
appear, 400 million years ago;
Pangaea forms, 260 million years ago;
dinosaurs become extinct, 65 million
years ago; human ancestors appear,
3.5 million years ago; continental
glaciers retreat, 20,000 years ago. The
time since the dinosaurs’ extinction is
relatively recent.
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Page 145
Reading Checkpoint The climate
cooled, causing continental glaciers to
advance and retreat over Earth’s
surface. Eventually, the climate
warmed and glaciers melted.
Reviewing Key Concepts
1 a Cambrian, Ordovician, Silurian,
Devonian, Carboniferous, Permian
b There was an invertebrate
“explosion” as many new life forms
appeared. c Climate change resulting
from continental drift 2 a Reptiles
b Possible answers: Mammals ate
smaller organisms than themselves,
such as insects, so they were not
competing with dinosaurs for food.
Mammals were small enough to hide
from dinosaurs. c Plant-eating
dinosaurs were food for the meateating dinosaurs. When the planteaters died out, there was no source of
food for the meat-eaters, so they also
died out. 3 a The Age of Mammals
b Dinosaurs had become extinct, so it
made way for the evolution of
mammals. Grasses evolved, which
provided food sources for larger,
grazing animals.
Writing in Science
Writing Mode Description
Scoring rubric: 4 Exceeds criteria,
includes a complete description of
organisms and events for all periods
of the era; description is accurate and
detailed 3 Meets all criteria, but
description is not detailed 2 Includes
only one or two of the periods
1 Includes inaccurate information
Page 146
Skills Lab
As Time Goes By
Expected Outcome Student will
become aware of the immensity of
geologic time, especially when
compared with the span of his own
life and the length of human history.
Analyze and Conclude
1 Answers will vary depending on the
height of the classroom. The height of
a classroom is typically about 2.5 m,
S cience T extbook A nswer K ey
or 250 cm. About 55 reams of paper
with a width of 4.5 cm each would be
needed to reach the ceiling. That
would represent 55 million years.
Only two events, the end of the last
ice age and the evolution of whales,
would fall on a ream inside the
classroom. 2 Answers will vary
depending on the figure obtained in
Question 1. At 55 reams per classroom,
about 84 classrooms (4,600 ÷ 55)
would be needed to represent the age
of Earth. About 9.5 (530 ÷ 55)
classrooms would be needed to
represent the time when vertebrates
appeared. 3 The thickness of the stack
would need to be about 20 times
higher (4,600 ÷ 225). 4 A typical
answer might suggest using different
colors of paper for each of the eras
and then marking the divisions
between periods with cardboard
dividers. Major events can be shown
with flags on sticks stuck in the stack.
5 Most students will think that the
scale is not practical. Advantages of a
1-m model include that it could easily
fit on a wall and that it could be used
for quick reference. Disadvantages
include that the time from the
beginning of the Paleozoic Era to the
present would be such a short length
that it would be difficult to include
many relatively recent major events.
Extend Inquiry
More to Explore Student’s version
will vary depending on the shape he
chooses. Have him use the geologic
time scale in the section
The Geologic Time Scale to mark the
divisions between eras and each of
their periods. Student might draw the
outline of a ribbon or spiral with a
black pencil and then use the colored
pencils to color in the era and period
lengths.
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Review and Assessment
Organizing Information a molds
and casts b trace fossils c amber
d ice
L essons 41–60
Reviewing Key Terms
1 a 2 b 3 b 4 d 5 c 6 true
7 petrified fossil 8 absolute age
9 true 10 asteroid hitting Earth
Writing in Science
Writing Mode Description
Scoring Rubric: 4 Exceeds criteria,
includes the different layers as shown
in figure 5 and the life forms that
existed at those times 3 Meets all
criteria but is not as detailed
2 Includes only brief description
1 Includes inaccurate information
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Checking Concepts 11 Sediment
covers the remains of an organism.
Then water rich in minerals seeps into
the spaces of the organism’s cells.
Over time, the water evaporates,
leaving the hardened minerals behind.
Petrified fossils also form by
replacement, in which minerals in
water make a copy of the organism.
12 A bony fish has a better chance of
leaving a fossil because it has hard
parts that do not decay quickly, but a
jellyfish does not have hard parts.
13 Sometimes, deeply buried layers of
rock are lifted up to Earth’s surface.
At the surface, the exposed rock
erodes away. Then sediments are
deposited on top of the eroded surface
of the older rocks and harden into
rock layers. The place where an old
eroded surface is in contact with a
newer rock layer is called an
unconformity. 14 A scientist would
use radioactive dating to determine
the absolute ages of intrusions and
extrusions near the sedimentary rock
in which the fossil was found.
15 Scientists think that the oceans
formed during the first several
hundred million years of Precambrian
Time. As Earth cooled, water vapor
condensed, forming rain. The
rainwater eventually accumulated to
form the oceans. 16 During the
Tertiary Period, Earth’s climates were
generally warm and mild. During the
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Quaternary Period, Earth’s climate
cooled, causing a series of ice ages.
Thinking Critically 17 The
paleontologists could conclude that
both rock layers formed at about the
same time. 18 Precambrian Time
begins with the formation of Earth 4.6
billion years ago and ends 544 million
years ago. Carbon-14 would be of no
use in dating the fossil because its
half-life is much too short. Therefore,
the uranium-235 would be better to
use. 19 Amphibians live part of their
lives in water, and reptiles are land
animals. When the climate became
drier, the amphibians had less water.
A drier climate, then, would favor
reptiles. 20 The movie would not be
scientifically accurate because
dinosaurs became extinct at the end of
the Mesozoic Era and humans did not
evolve until well into the Cenozoic
Era, over 60 million years later.
Math Practice
21 After 9 half-lives, 0.1953125
percent of a radioactive element will
remain.
Applying Skills 22 According to the
law of superposition, layer 1 is the
oldest layer and layer 4 is the
youngest. 23 A scientist must have
used radioactive dating to determine
the ages of the intrusion and
extrusion. 24 Layer 3 is younger than
the 60-million-year-old intrusion but
older than the 34-million-year-old
intrusion. 25 Layer 4 is younger than
the 34-million-year-old intrusion but
older than the 20-million-year-old
intrusion.
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Standardized Test Prep
1 C 2 J 3 A 4 G 5 B 6 Possible
answer: Scientists study the position
of sedimentary rock layers to
determine the relative ages of rocks by
comparing where the rocks lie in
relation to each other. According to
the law of superposition, rocks on the
bottom layers are generally younger
than rocks on the top layers. Index
S cience T extbook A nswer K ey
L essons 41–60
fossils are also used to date rock
layers. Scientists make use of the
process of radioactive decay to find
the absolute ages of igneous rock.
They identify and measure the
amount of a radioactive element in a
rock and determine its half-life.
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Answer Keys
Lessons 41–60
Science
Manual Exercises
Lesson 54
Application The sediment that
formed layer 3 could not have been
deposited underneath the hardened
rock of layer 4. Answers in chart will
vary.
Lesson 57
See the circle graph at the end of this
section.
1 The components in the atmosphere
are different amounts. 2 Early lifeforms gave off oxygen as a waste
product.
Earth’s Early Atmosphere
Nitrogen
5%
Other Gases
3%
Carbon Dioxide
92%
Oxygen 0%
Today’s Atmosphere
2
Other Gases (including CO )
1%
Oxygen
21%
Nitrogen
78%
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Science
Activities
Answer Keys
Lessons 41–60
© Pearson Prentice Hall
Activity 15
Activity 18
It’s Creepy
Researching a Geologic Time Period
(Science Lesson 44)
(Science Lesson 56)
1 creep 2 Water expands when it freezes. 3 The rock and
soil particles rise because the water between them freezes
and expands. 4 They rise perpendicular to the slope of the
hill. 5 They fall when the ground thaws. 6 They fall down
vertically toward the center of Earth. 7 Water seeps into
the ground, filling spaces between soil and rock particles.
When that water freezes, it lifts the particles up,
perpendicular to the hill. When the ground thaws, the
particles fall down vertically. The result is movement
downhill.
Answers will vary.
Activity 16
Great Rivers of the World
(Science Lesson 46)
1 They are ranked on the basis of volume of flow. 2 The
Mississippi has a volume of flow of 17.400 m3/s, while the
Amazon has a volume of flow of 140,000 m3/s, or about
eight times as much. 3 Nile River 4 The Amazon has the
longest drainage basin. 5 Almost all encyclopedias contain
an entry for each of these rivers. Student could also find
these rivers on a world map and then use an atlas.
Activity 17
Glaciers
(Science Lesson 49)
1 moraine 2 erosion 3 erosion 4 kettle 5 erosion
6 erosion 7 deposition 8 A valley glacier is a long, narrow
glacier that forms in a mountain valley. A continental
glacier is a glacier that covers much of a continent or large
island. 9 They form in areas where more snow falls than
melts. Snow builds up, and pressure compacts snow,
forming ice that then begins to move downhill. 10 Once
the depth of a glacier reaches about 30–40 meters, the
glacier begins to move downhill because of gravity.
11 When a glacier melts, it deposits sediment.
12 plucking and abrasion 13 Deposition occurs when the
glacier melts and leaves rock and sediment on the land.
14 plucking 15 ice ages 16 glacier 17 till
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