Reading Comprehension - Passage: "Planet Earth: Our Place in Space!"

Contributed by:
This passage talks about our home planet, Earth, and its relative characteristics compared to other planets in the Solar System.
Planet Earth!
Our Place in Space
2. The word “Earth” is defined in 2 ways:
1) this planet, our home, and...
2) soil or dirt- which make up planet Earth’s surface

3. Planet Earth! Be nae
med eu eee tae)
+ Location and Neighbors
— Our solar system
+ Movement

— Tilting, spinning, and rotating
+ Features
— Layers
— Continents and Oceans
— Landforms
+ History
— From its beginnings to today
* Maps
— How to get to know Earth better

Bas aN

4. Location and Neighbors: Our Solar System
+ It may appear that we live in a busy neighborhood, right? There are planets, moons, our own star-
the Sun, comets, meteors, asteroids, but mostly- there 1s a lot of space, nothingness!
* Millions and millions of miles separate us from each other. Our neighborhood is a very safe place,
we never seem to bump into one another!
+ The Sun helps keep the neighborhood together. It is huge and because of the force of gravity it
continually pulls on its neighbors, keeping them close and circling around it.

5. Location and Neighbors: Our Solar System
* Our 2 best buddies in our Solar System are the Sun and Moon
+ Weare the third planet from the Sun. We travel around the Sun with our Moon. So do the other 8
planets (9 in total including us). They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus,
Neptune, and Pluto.
* We all rotate around the Sun... at different
distances, speeds, and circles- called orbits.

6. Location and Neighbors: Our Solar System
You can even have your own set of marble planets... and you don’t have to travel millions of miles to
see them up close!
Can you pick out which marble looks most like Earth?

7. Do you remember us saying that the Earth travels around the Sun? Well, it also
spins. And it tilts. It is moving in different directions all at the same time. Let's look
at these images and then discuss each to help us understand these movements:

Our tilt/tip

Round and
Round we Spin
Rotating/Circling Around the Sun
8. Movement: Tilting
Scientist believe that several millions of years ago, when the planets were still
forming, another and smaller planet collided with Earth (see picture), causing it to
tip or tilt. The Moon formed from what bounced off the Earth in this impact.
This tilt never changes during Earth’s orbit and is called an “axis.” We spin on this
axis. The seasons we experience are a factor of the tilt and not how close we are to
the Sun.

9. Movement: Spinning
Our solar system formed out of a gas cloud and dust. All this came together by the force of
gravity. The dust and gas was already whirling around in a circle. As it all clumped
together to form the Sun and planets, these new objects started to spin — and
then spin faster. We will discuss this some more in the section called History.

The Earth spins at 1,000 miles per hour. It takes 24 hours... 1 day, for it to complete one
revolution or turn. Why don't we fall off? Well, we are traveling with the Earth, its oceans,
and atmosphere. This is the same reason we do not feel any movement.

Are you worried the Earth might stop spinning?
Don’t be! We are in space. iter sao
friction, nothing to slow us down, We've been
here, doing the same thing for millions of years.
Ahthh, good to know, right!?

10. Movement: Rotating
The Earth rotates around the sun because of the sun's gravitational pull —
Earth keeps moving forward, and the gravitational pull means it travels, or rotates
around the sun. You can see this work yourself at home using a ball and string. Try
it-you are the Sun; the ball is the Earth. That's how it is with the Sun and Earth. The
Moon rotates around the Earth in the same way.

The path Earth travels is not a perfect
circle but an oval. The Earth is closest to
the Sun in January and furthest in July.
This seems odd but remember, it is the
tilt of the Earth that causes our seasons,
not our distance to the Sun.

Movement: What About Our Friend Mr. Moon?
While the Earth spins and rotates around the Sun, the Moon circles around td
the Earth. Strangely, it spins with us, so we only see one side of the Moon! Only
satellite's and astronaut’s on missions to the Moon have seen “the far side of the Moon.”

Our Solar System is very unusual, isn't it?
What do you think the far side of the moon looks like?
Features: Layers of the Earth
Based on all we've learned about whirling gases and dust you might think the
Earth simply formed into a big rock. Far from that! The Earth is like an onion. It
has several, very different layers.

* Crust: Earth’s surface of rock, minerals, sand, water, and dirt of all types.
The Crust is the thinnest at only a few miles and is the coolest layer.
Mantle: This is the thickest layer. The pressure here is immense, very hot,
rock-like, and while solid it is actually a super-thick liquid. Over time it pushes
to the surface (volcano lava) and causes the crust to move (shifting landforms and

* Quter Core: Like the Mantle, the outer core flows crt _]
over time. It is made of liquid metals. — Mantle

Inner Core: This is very hot, dense, and solid metal. {Inner Core
Itis just a big ball of heavy, heavy iron.
Outer Core
13. Features: The Atmosphere is a Layer Too
Our 6,000-mile high atmosphere- the air we breathe, that breeze we feel, where we
fly our kites, the clouds we see, and storms, make up another of Earth’s layers. Our
atmosphere has its own 5 layers. After that we are truly in outer space. The
atmosphere moves with the Earth as it spins on its axis and rotates around the Sun.
The lowest level of the atmosphere is warmest and where we find most air, oxygen,
moisture (clouds), and where airplanes and hot-air balloons fly. Temperatures get
less and less as you go up, so does oxygen for breathing.
Satellites and spacecraft travel above our atmosphere, in space.

14. Features: Continents and Oceans
Earth is home to 7 large land masses, called continents and 5 oceans.
Each has different landforms (this includes the ocean floor), weather,
people, plants, and animals.
7 Continents 5 Oceans
+ North America + Pacific
* South America * Atlantic
+ Europe * Arctic
eA brica * Southern
+ Antarctica * Indian
+ Asia
* Australia

SE egg

15. Features: Continents
Some interesting facts to know about Earth’s Continents include:
The United States is a part of North America, along with Canada,
Mexico, and Greenland- the worlds largest island
Asia is the largest and Australia the smallest of the Continents
As early explorers discovered North and South America, they
became known as the “New World”
Scientists have thought that the continents were once one large
land mass
Continents are always moving... you will remember that we learned
the flow of the Earth’s Mantle causes movement of the Earth’s Crust

16. Features: Oceans
Some interesting facts to know about Earth’s Ocean’s include:
The Ocean’s cover 70% (most) of Earth’s surface
The Ocean’s contain saltwater, not the fresh water we drink that
comes from rivers and lakes
Just as the Continents once formed 1 large land mass the Ocean’s
were 1 large body of water
All the Ocean’s are connected. The Continents are not
Like land, Ocean floors have their own special features. For
example, the Mariana Trench in the Pacific Ocean is 7-miles deep!


18. Features: Landform Examples Hix

How many of these landforms can you name?
The history of Earth is filled with amazing events that go back BILLIONS of years; yes,
billions...actually 4,500,000,000! Here are some special events along this very long
formation of Earth. We call this a timeline:
+ Rocks and dust whirling around our new Sun, slowly form into planets — and Earth
+ Water collects on Earth and small micro-organisms appear, so do early continents
Earth undergoes major changes- from several ice ages, to asteroid impacts and
temperatures that kill everything, to the dinosaurs, to movements of the continents,
and to the growth of many different plants and animals, to another killer asteroid
+ The Earth then begins to look more like we see it today. This includes the appearance
of humans, more land and sea creatures, vegetation, and changing landforms like
glaciers, mountains, plains, and deserts as we discussed earlier in this lesson
From Earth’s creation billions of years ago to a more familiar look from millions of years
ago we have a rich history to learn about and appreciate. Take a look:
Maps: How to get to know Earth better
Imagine trying to go someplace- anyplace, without knowing how far it is and what
turns are needed to get there. Try this- explain to a friend how to get to your house...
was that easy or hard? What if you were to make a drawing that showed the streets and
houses... easier?
Maps are drawings or images of places. We need maps to teach us about the
Earth... its history, where to find water, how far to travel, obstacles to getting
somewhere, and much more. There are a lot of different kinds of maps. Who uses
Car and truck drivers
Ship captains
Airplane pilots
+ Hikers
+ Ambulance drivers
+ YOU AND ME! Let’s look at some different maps next

22. REG ws
. ——

23. School Map (istfloor)

25. The End
To challenge yourself on all
you leamed try completing
ihe Planet Earth Activity
You can do it!