8th Grade Science

Directed Reading Packet

Astronomy

Name: ___________________________

Teacher: _____________ Period: _____

Chapter 1, Section 1: Telescopes

Introduction

1. What makes astronomy different from all other branches of science?

2. ___________________ are one of the only actual objects that astronomers can observe and study

directly and in person.

Electromagnetic Spectrum

3. The way astronomers study the parts of our universe is by observing _________ (the visible part of

the electromagnetic spectrum).

The Speed of Light

4. How do we define a light year, AND about how big is this unit in kilometers?

5. What is the nearest star to our solar system, AND how far away is it?

Looking Back in Time

6. Why can’t we see what the Andromeda galaxy actually looks like?

Electromagnetic Waves

7. In EM waves, the ____________________ is the distance between two wave crests, whereas the

______________________ is the number of wavelengths per second.

The Electromagnetic Spectrum

8. Label the diagram below:

9. A. What types of objects emit gamma and X-rays?

B. What about radio waves?

Types of Telescopes

10. Optical telescopes come in two basic types: refracting and reflecting. What’s the difference between the two? Which kind is better at collecting light?

11. _____________ telescopes (which collect radio waves) look like a __________________________.

12. What’s unique about the Arecibo Observatory in Puerto Rico?

13. The Hubble telescope is the most well-known ___________ telescope. This type of telescope avoids

interference and can form extremely clear images, since it is in _______________ above the Earth’s

_______________________.

Observations With Telescopes

14. The Greek word for planet, means “wanderer”. Why do you think this is?

15. Galileo was the first astronomer view the night sky through a telescope. What did he discover about each of the following?

A. The Milky Way

B. The Moon

C. Venus

D. Jupiter

16. In addition to telescopes, modern astronomers also use a tool called a ______________________ to

analyze the different wavelengths emitted by distant objects.

Summary

Astronomers study _______________ from stars and galaxies.

Visible light is part of the _______________ _______________.

_______________ make distance objects appear both nearer and larger. You can see many more stars

through a _______________ than with the unaided eye.

A _______________ produces a spectrum from starlight. _______________ can learn a lot about a star

by studying its _______________.

Chapter 1, Section 2: Early Space Exploration Satellites

1. One of the first uses of _______________ in space was to launch satellites.

2. What is a satellite?

3. List 4 natural satellites:

How Satellites Stay in Orbit

4. Isaac Newton demonstrated how objects stay in orbit using a famous thought experiment involving the

launching of a _____________________ at extremely high speed.

5. List three common uses for artificial satellites:

6. How is it possible for communications satellites to stay at the same exact spot above the Earth’s surface if they’re orbiting at thousands of miles per hour?

The Space Race

7. The Cold War was between the __________________ and the ____________________. During this

time, both nations worked to increase their weapons arsenal, until the year __________.

8. What was Sputnik?

9. What did the United States do in response to the Sputnik program?

10. List the important event the happened on each date below:

October 4, 1957

November 3, 1957

January 31, 1958

April 12, 1961

February 1962

May 25, 1961

July 20, 1969

December 11, 1972

Exploring Other Planets

11. A __________________________ is an unmanned spacecraft., which collects data by flying near or

landing on an object in space.

12. Which three planets have probes actually landed on?

13. Why do you think space probes never landed on Jupiter, Saturn, Neptune or Uranus?

14. Which probes are now beyond the edges of the inner solar system?

Summary

A _______________ orbits a larger object. ___________ are natural satellites.

Newton’s law of ____________________________ explains how the force of gravity works, both on

Earth and across space.

_________________ holds satellites in _______________.

_______________________ satellites are used to take pictures of Earth and other planets, for

____________________ and for ______________________.

The launch of the ________________ satellite started the ______________________ between the US

and the Soviet Union.

The United States’ ________________ mission put the first humans on the ____________.

The US and Soviet Union also sent several ______________ to other planets.

Chapter 2, Section 1: Planet Earth Earth’s Gravity

1. ______________ and _____________ orbit each other. This Earth-Moon system orbits the ___________

in a regular path.

2. Earth’s gravity pulls the Moon toward _____________________. Without gravity, the Moon would

continue moving in a _____________________ into space.

3. What two things does the strength of gravitational force depend on?

Earth’s Magnetism

4. What gives the Earth its magnetic field?

5. How is this magnetic field helpful for life on Earth?

Earth’s Motions

6. What’s the difference between rotation and revolution?

7. Along with the Sun, the Moon, stars, planets and everything else in the night sky also rise in the

__________ and set in the __________.

8. What makes them look like they’re rising and setting?

Earth’s Seasons

9. TRUE / FALSE: Earth’s seasons are due to the Earth being closer or farther away from the Sun.

10. We have seasons on Earth because the axis is tilted at an angle of ________ degrees.

11. In the Northern hemisphere, summer begins on _______________. This is the longest __________ and

the shortest ___________ of the year.

12. The hemisphere that is tilted away from the Sun is __________ because it receives less __________ rays.

13. Draw a diagram showing the orientation of the Earth and Sun in summer (for the Northern hemisphere):

14. Look at the diagram you just drew. If it’s summer for us, what season would it be in Australia, and WHY?

Earth’s Revolution

15. How long does it take the Earth to make a complete revolution around the Sun?

16. What shape is the Earth orbit (along with all the planets)?

17. It takes Mercury only _______________ to orbit the Sun, while it takes Saturn _________________.

18. Finish this sentence: The farther away a planet is from the Sun, the…

Summary

The planets in our solar system all spin as they ____________ around the Sun in fixed paths called

___________.

The balance between ____________ and our motion around the Sun, keep the planets in orbit.

Earth has a _______________________, created by motion within Earth’s outer ___________ iron core.

The magnetic field shields us from harmful _______________.

Earth rotates on its axis once each ____________ and revolves around the Sun once every __________.

The ___________ of the Earth’s axis produces the seasons.

Chapter 2, Section 2: Earth’s Moon

Introduction

1. What was the name of the missions that sent people to the moon (and back)?

2. No astronauts have visited the moon since __________.

Lunar Characteristics

3. How big is the Moon compared to the Earth’s size?

4. How strong is the Moon’s gravity compared to Earth?

5. When we see a full Moon (or any other lunar phase), it looks like the Moon is shining. Why is this?

6. Why do we always see the same side of the Moon from Earth?

7. Why do you think the Moon has no atmosphere? (HINT Look back at question 4.)

8. Temperatures on the Moon range from ___________ to ___________.

9. In 1969, Neil Armstrong was the first man to set foot on the Moon. Do you think his footprints are still

there on the lunar surface? Why or why not?

Lesson Summary

Evidence suggests that the Moon formed when a ________ sized planet ______________ with the Earth.

The Moon makes one _________________ on its axis for each ______________ around the Earth.

The Moon is made of materials similar to the Earth and has a ____________, mantle, and ____________,

just like Earth.

Chapter 2, Section 3: The Sun

Introduction

1. Our Sun is just one _________ among hundreds of billions of others in our galaxy.

2. The Sun makes up ___________% of the mass of the solar system.

3. Look at Fig. 2.11: If the Sun were the size of a basketball, how big would the Earth be in comparison?

Layers of the Sun

4. What is the Sun made of?

5. Describe each of the three inner layers of the Sun:

Core

Radiative zone

Convection zone

6. Which of these three inner layers is the source of the Sun’s energy? _____________________

7. Which layer does it take 50 million years for light energy to travel through? _____________________

8. In which layer does hot material rise, then cool and sink back down again? _____________________

The Sun’s Atmosphere

9. Use the circle on the right to

represent the Sun. Draw in the

three layers of the Sun’s

atmosphere. Label their names

AND their temperatures.

10. Which of these layers is the one

that we see shining?

11. What is the temperature of this layer?

12. When is the Sun’s corona actually visible to us?

Surface Features of the Sun

13. The most noticeable activity of the Sun is the appearance of _______________, which are ___________,

darker areas on the Sun’s surface.

14. Sunspots fluctuate on a cycle of about _______ years.

15. What happens when a loop of the Sun’s magnetic field breaks?

16. How is it possible that solar activity can cause damage 93 million miles away, here on Earth?

17. At certain times, solar particles interact with the Earth’s magnetic field to produce another effect that is

visible in our sky. What is the name of this spectacular phenomenon, which you’ve probably heard of?

(HINT You’d have to go north to see it.)

Solar Prominences

18. In a solar prominence, ____________ flows along a loop that connects ______________.

19. How long can solar prominences last?

Summary

The mass of the Sun is _________% of the mass of our solar system.

The Sun is mostly ______________ with smaller amounts of _______________. The material is in the

form of _______________.

The main part of the Sun has three layers: the ___________, the radiative zone, and the

________________ zone.

The Sun’s ____________________ also has three layers: the ____________________, the

chromosphere and the ________________.

Nuclear ______________ of hydrogen in the core of the Sun produces tremendous amounts of energy

that ________________ out from the Sun.

Chapter 2, Section 4: Moon Phases and Eclipses

Introduction

1. What is the opposite of a full moon? ______________

Solar Eclipses

2. Describe in what happens during a solar eclipse.

3. Draw a sketch of positions of the Earth, Moon and Sun during a solar eclipse.

4. What is the difference between the umbra and penumbra?

5. What is the difference between a partial and a total solar eclipse?

6. Draw sketches of what you think these solar eclipses would look like as seen from Earth.

A Lunar Eclipse

7. Describe what happens during a lunar eclipse.

8. Draw a sketch of positions of the Earth, Moon and Sun during a lunar eclipse.

The Phases of the Moon

9. Why do we see the illuminated moon? Where does the light come from?

Partial solar eclipse in North America – 10/23/14 Total solar eclipse in North America – 8/21/17

10. What causes the full moon?

11. A full lunar cycle (from one new moon phase to the next) takes _______ days.

12. What lunar phase will you see 7.4 days after the new moon? ____________________

13. What lunar phase will you see in another 7.4 days? ____________________

14. What lunar phase will you see in another 7.4 days? ____________________

15. After another 7.4 days, the lunar phase is back to a ___________________ again.

16. What shape would the moon be just a day before or after the new moon? ___________________

17. Sketch the relative postions of the Earth, Moon and Sun during moon phases.

Summary

When the ____________ moon comes between the Earth and the Sun along the ecliptic, a

_____________ eclipse is produced.

When the Earth comes between the __________ and the Sun along the ecliptic, a _____________

eclipse occurs.

Observing the Moon from the Earth, we see a sequence of _______________ as the side facing us

goes from completely _______________ to completely _______________ and back again every

______ days.

New Moon First-quarter Moon

Last-quarter Moon Full Moon

Earth M Sun Sun

Sun Sun

Chapter 2, Section 5: Tides

The Tides

1) What is the primary cause of the tides? _____________

2) What is the secondary cause of the tides? _____________

3) Why does the Moon have a greater effect on the tides than the Sun?

4) Draw a sketch of the Moon, Earth and tidal bulges being generated. Label the areas experiencing high and low tides.

5) Each day, there are ________ high tides and _______ low tides.

Tidal Range

6) What is tidal range?

7) What factor determines an area’s tidal range?

Monthly Tidal Patterns

8) Draw sketches of the Moon, Earth and Sun during spring tides and neap tides.

Summary

The primary cause of the tides is the _______________ attraction of the Moon, which causes

__________ high and __________ low tides a day.

When the Sun’s and Moon’s tides match, there are _______________ tides; when they are opposed,

there are _______________ tides.

The difference between the daily high and daily low is the _______________ range.

Spring Tides Neap Tides

M S E

S E

S E

S E

Chapter 3, Section 1: Stars

Introduction 1) What is a star?

2) We live in a galaxy called the Milky Way, which is a collection of hundreds of billions of stars. Do you think all the stars we see in the night sky are part of our own galaxy? Why or why not?

Constellations

3) Are the stars that make up the constellation Orion actually close to each other in space? Explain.

4) Are the stars in Orion similar to each other at all? __________

5) Do the constellations change over time? __________

6) Why do constellations move across the sky from dusk to dawn?

7) Why do we see different constellations in summer than in winter? Energy of Stars

8) The Sun is just an __________________ star, but it appears much bigger and brighter than any of the

other stars because it is very ________________.

9) The process the powers the core of a star and releases so much energy is called nuclear ____________.

10) Describe this process:

How Stars Are Classified

11) TRUE / FALSE: Red means hot and blue means cold.

12) What color are the hottest stars? ________________

13) What color are the coolest stars? ________________

14) What class (letter) stars are the hottest? __________

15) What class (letter) stars are the coolest? __________

16) Fill in the chart below with the correct information regarding spectral class:

Star Classification

17) Look back at the chart from the Flexbook. Which spectral class (letter) do most stars belong to? _____

18) What is the name of these super-common small, cool stars? ____________________

Lifetimes of Stars

19) Write a quick description of each stage of a star’s life cycle:

Formation

Main Sequence

Red Giant

White Dwarf

Supergiant

Phrase Spectral

class Color

Temperature (Kelvin)

Oh Blue

Be

A

6000 – 7500 K

Good

Orange 3500 – 5000 K

M

Supernova

Neutron Star

Black Hole

Measuring Star Distances

20) What unit do scientists use to measure distances between stars? ____________________

21) Define a light year:

22) Look at the following picture of a star system.

What’s different about it compared to our own Sun?

Summary

A star generates ____________ by nuclear _____________ reactions in its core.

The ___________ of a star is determined by its surface _____________________.

Stars are classified by color and temperature. The most common system uses the letters:

_____ _____ _____ _____ _____ _____ _____ (from hottest to coolest)

Stars form from clouds of ___________________ called nebulas. Nebulas _______________ until

nuclear fusion starts.

Stars spend most of their lives on the _________________________, fusing hydrogen into helium.

Sun-like stars expand into ___________________, and then fade out as ____________________ stars.

Very massive stars expand into red ________________________, explode in supernovas, then end up as

neutron stars or ____________________.

Star distances can be measured in a number of creative ways.

Many stars orbit another star to form a ______________ system.

Chapter 3, Section 2: Galaxies

Introduction 1) What is a galaxy?

2) How many stars are in a galaxy? _____________________

3) How many galaxies are there in the universe? _____________________

Star Clusters 4) Look at this picture of the Pleiades star cluster.

Based on its appearance, is this an open cluster or a globular cluster? How can you tell?

Types of Galaxies

5) Which do you think is bigger: a star cluster or a galaxy?

6) What is the name of our closest galactic neighbor? _______________________

7) How far away is this galaxy? ____________________________

8) Draw a quick sketch of each of the three main galaxy types:

Spiral Elliptical Irregular

9) What gives spiral galaxies their shape?

10) How did irregular galaxies get so irregular?

11) Why do you think the oldest, largest galaxies in the universe tend to be elliptical in shape?

Pleiades star cluster

The Milky Way Galaxy

12) What does the Milky Way galaxy look like to us?

13) Why does the Milky Way look different than other galaxies?

14) Record the following data about our galaxy:

Type (shape) = ____________________________

Number of stars = _________________________

Length = _______________________________

Thickness = _____________________________

15) Where is our own solar system located in the Milky Way? How do you think we can tell this?

16) Does our Sun stay in the same place in the galaxy? Explain:

Summary

_______________ clusters are groups of ______________ stars loosely held together by gravity.

_________________ clusters are spherical groups of ________ stars held tightly together by gravity.

_______________ are collections of millions to many billions of stars.

Spiral galaxies have a _________________ disk of stars and dust, a ______________ in the middle, and

several _________________ spiraling out from the center.

Typical elliptical galaxies are __________ shaped, red or yellow, and contain mostly __________ stars.

___________________ galaxies were deformed by other galaxies.

The band of light called the Milky Way is the disk of our galaxy, which is a typical ____________ galaxy.

Our __________________ is in a spiral arm of the Milky Way galaxy, a little more than _______________

from the center to the edge of the disk. Most of the _________ we see are in our spiral arm.

Chapter 3, Section 3: The Universe

Introduction

1) What objects are included as part of the universe?

2) Who discovered the exitence of other galaxies? _______________________ The Expanding Universe

3) What connection did he notice led him to the discovery that the universe is actually expanding? What is this law now called?

4) As the universe expands, what is actually expanding? The Big Bang Theory

5) As best we can tell, how old is the entire universe? _______________________________

6) If galaxies are moving apart, at one point, they must have once been ____________________.

7) Do you think we can know what happened BEFORE the Big Bang? Why or why not?

After the Big Bang

8) What did the universe look like immediately AFTER the Big Bang?

9) What was the first element to form? ___________________

10) What caused all the matter of the universe to start clumping together into gas clouds, stars, galaxies, star clusters, etc.?

11) Draw a series of pictures that depict what the universe looked like at various stages up until the present:

Before Big Bang During Big Bang Early Universe Present Universe

Dark Matter

12) How can we know that “dark matter” exists if we can’t see it and don’t even know what it is?

13) What do scientists think dark matter might be made of?

14) TRUE / FALSE: There seems to be way more ordinary matter in he universe than dark matter. Explain.

Dark Energy

15) What is the “Big Crunch”, and does it seem to be true or not?

16) What role does dark energy play in the eventual fate of the universe?

17) If the universe just keeps expanding and expanding forever into the future, what do you think it will eventually look like? (What will happen to stars and planets? Will conditions still support life?)

Summary

The _______________ contains all matter and all energy as well as all of __________________________.

We can see that galaxies are moving ________________ which tells us that the universe is ___________.

In the past, the universe was squeezed into a very small ________________.

The ______________________ theory proposes that the universe formed in an enormous explosion

about ____________________ years ago.

Recent evidence shows that there is a lot of matter in the universe that we cannot __________. This

matter is called ____________________.

The rate of the expansion of the universe is ___________________. The cause of this increase is

unknown; one possible explanation involves a new form of energy called __________________.

Chapter 4, Section 1: Introduction to the Solar System

Introduction

1) Name the objects that make up our solar system: Changing Views of the Solar System

2) Why do you think the ancient Greeks think there were only five planets?

3) How can planets be distinguished from the rest of the stars in the night sky? Earth at the Center of the Universe

4) Why did the ancient Greeks (and almost everybody until the 1600s) think the universe was geocentric?

5) Draw a basic diagram of this geocentric model, and label the planets in their orbits around the Earth.

The Sun at the Center of the Universe

6) To the right is a diagram drawn by Copernicus. What does it depict?

7) Why didn’t Copernicus publish his theory while he was still alive?

8) Who expanded on Copernicus’ ideas by making observations of the night sky with a telescope?

Planets and Their Motions

9) Look at the data table listing the mass and diameter of each planet compared to the Sun.

A. Which planet is the most similar to Earth in terms of size? ___________________

B. Which planet is the smallest? ___________________

C. Jupiter is about _____ times the mass of Saturn? 2 3 5 10 100 (choose one)

D. How would you describe the overall differences between the four inner planets and the four outer planets?

What is (and is not) a planet?

10) Why is Pluto now considered a dwarf planet?

11) Is Pluto the only dwarf planet? YES / NO

The Size and Shape of Orbits (circle one)

12) Which shape accurately depicts how most of the planets orbit the Sun?

13) Define astronomical unit (AU):

14) 1 AU = _____________________ km = _____________________ miles

15) Look at the data table showing relative distance between each planet and the Sun.

A. Which planet has the shortest day? ________________________

B. Which planet has the longest day? ________________________

C. Which planet has the longest year? ________________________

D. Which planet has the shortest year? ________________________

E. Is there any connection between a planet’s distance from the Sun and the length of its day? _____

F. Is there any connection between the length of a planet’s day and the length of its year? _____

G. Is there any connection between a planet’s distance from the Sun and the length of its year? _____

The Role of Gravity

16) What holds the planets in orbit around the Sun? _____________

17) What would happen to the Earth’s motion if the Sun suddenly disappeared?

Extrasolar Planets

18) What is an exoplanet?

19) Since exoplanets are too small and distant to actually see, how can we detect their presence?

Formation of the Solar System

20) What are the two clues that tell us how our solar system formed?

21) What is the solar nebula hypothesis?

22) What happens to a nebula as it contracts, getting smaller and smaller?

23) How old is the solar system? _______________________

24) The __________ was the first object to form in the solar system.

25) Why did the outer planets turn out so differently than the inner ones?

Summary

The Sun and all the objects held by its ____________ make up the _____________________.

There are ____________ planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, and

Neptune. Pluto, Eris, Ceres, Makemake and Haumea are ____________________.

Ancient Greeks believed Earth was at the ___________ of the universe and everything else orbited Earth.

Copernicus proposed the _________ as the center of the universe, the planets and stars orbiting the Sun.

Planets are held by the force of gravity in _______________ orbits around the Sun.

The solar system formed from a giant _______________ and dust about _______________ years ago.

This model explains why the planets all lie in one _____________ and orbit in the same ______________

around the Sun.

Chapter 4, Section 4: Other Objects in the Solar System

Introduction

1) Where did the asteroids and comets come from?

Asteroids

2) List 5 facts about asteroids:

3) How much mass do all the asteroids in the asteroid belt amount to?

4) What prevented all these rocks from coming together to form their own planet?

5) How many near-Earth asteroids are there? ____________

6) How many of these are considered very large (over 1 km in diameter)? ______________

7) What do you think it would feel like to stand on a large asteroid? (HINT Think about how much gravity an object of this size has.)

Meteors

8) What is the difference between a meteoroid, a meteor and a meteorite?

Meteoroid

Meteor

Meteorite Comets

9) What are comets made of?

10) How does a comet’s orbit compare to the orbit of the planets and asteroids?

11) What gives a comet its tail?

12) Draw the comet’s tail in the diagram below. (HINTS (1) The tail only appears when the comet gets close to the Sun and should be most prevalent when it’s closest. (2) The tail should always extend out AWAY from the Sun.)

13) Why do we only see Halley’s comet once every 75 years?

14) Where do most short-period comets originate? ______________________

15) Where do most long-period comets originate? ______________________

Dwarf Planets

16) Why was Pluto finally demoted from official planetary status? (What was discovered?)

17) What are some of the unusual characteristics of Pluto?

18) Name four other dwarf planets besides Pluto:

Summary

Asteroids are ________________ shaped, rocky bodies that orbit the Sun. Most of them are found in the

____________________, between the orbits of Mars and Jupiter.

_____________________ are smaller than asteroids, ranging from the size of boulders to the size of sand grains.

When meteoroids enter Earth’s atmosphere, they vaporize, creating a trail of glowing gas called a _____________.

Comets are small, icy objects that orbit the Sun in very ___________________ orbits. When they are close to the

Sun, they form comas and ________________, which glow and make the comet more visible.

___________ planets are ________________ bodies that orbit the Sun, but that have not cleared their orbit of

smaller objects. _____________ is a dwarf planet in the asteroid belt. Eris, Pluto, Makemake and Haumea are

dwarf planets in the ______________ belt.

S