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TEACHER
RESOURCE
PLANETARIUM
&
RY
TO
VA
ER
BS
O
E
M
O
RD
A
ST
VITIES ON...
H
T
R
A
E
HELLO
TI
FACTS, RESOURCES AND AC
THE COMPOSITION
OF THE EARTH
diameter
from the Sun and with a
Earth is the third planet
four inner, rocky,
the
of
est
larg
the
is
it
,
of around 12,000 km
planet in
tem and the fifth largest
planets of our Solar Sys
y planet that
onl
the
also
is
th
Ear
.
the entire Solar System
d Earth’s
form of life. We’ve divide
we know of, that has any
before and after life.
history into two parts –
a vast,
e 4.6 billion years ago from
Earth began forming som
the
of
n
atio
over from the form
swirling disk of debris left
ris
deb
the
of
gas
and
t
the dus
Sun. Gravity slowly pulled
re and more
mo
in
led
pul
n
the
ich
cloud into clumps wh
go on to
er. These clumps would
material, growing ever larg
esimals.
net
pla
ll planets known as
become asteroids and sma
the
e
tim
r
ove
er;
eth
l things tog
Gravity continued to pul
h one
s collided and merged wit
planetesimals and asteroid
est
larg
the
w
gre
t
tha
se
again. Tho
another, growing larger
uding Earth.
incl
,
tem
Sys
ar
Sol
our
became the planets of
net very hot.
created Earth left our pla
All of the collisions that
This let light
.
t much of it was molten
The Earth was so hot tha
toward the
t
floa
gen
oxy
carbon and
materials such as silicon,
tals such as
me
als,
teri
ma
vy
hea
ile
surface of the Earth wh
Earth.
k toward the centre of the
iron, gold and uranium san
of the Earth and
tre
cen
the
at
still
are
These heavy materials
up the
e of the stuff that makes
form the Earth’s core. Som
t. Because of
hea
of
lot
a
tes
era
gen
core is radioactive and
as the
e of Earth remains as hot
this radioactivity, the cor
, even though
lten
mo
still
is
t
par
in
,
surface of the Sun and
cooled substantially.
the rest of the Earth has
molten
Earth has a hot, partially
It’s a good thing that the
molten
the
ct,
effe
o
am
ed the dyn
core. Due to a process call
covers our
ich
wh
d
fiel
tic
gne
ma
a
core of the Earth makes
Sun
harmful radiation from the
planet and protects it from
protective
this
e
hav
n’t
did
th
Ear
If
known as the solar wind.
elop on
have had a chance to dev
force field, life may never
our planet!
million
d forming within 10 to 20
The Earth largely finishe
rs its surface
yea
lion
mil
d
dre
hun
years. After another few
ous
that one of the most fam
had cooled down enough
water
uid
Liq
er!
wat
be:
to
e
features of our planet cam
The mantle
is 67% of
Earth’s mass and
is 2,900 km
thick.
The core is
33% of Earth’s
mass and has
a radius of
3,430 km.
While we know that the Earth is over
4 billion years old, finding the exact age is
very difficult because the rocks used to date
Earth formed slowly from the molten mass.
tem but
y common in the Solar Sys
specifically. Water is ver
ced in our
pla
ly
nice
is
th
Ear
e
aus
is usually found as ice. Bec
water
from the Sun that all its
Solar System it isn’t so far
t all its water
tha
Sun
the
to
se
clo
so
freezes into ice, nor is it
called
and not too cold, and is
boils away. It’s not too hot
‘The Goldilocks Zone’.
teria,
life forming on Earth – bac
In part two we’ll look at
!
ans
hum
jellyfish, dinosaurs, and
Download a FREE Earth poster here...
www.stardome.org.nz/wp-content/uploads/2015/03/
Stardome_Education-Planet-Posters-2014_Earth.pdf
DISCUSSION
POINTS
How did tmhe?
Moon for HIs Earth still changing?
ow do we see
in the Earth’s changes
surface?
The crust is
less than 1%
of Earth’s mass
and is 5–100 km
thick.
SCIENC
CONTEN E
T/
CURRICU
LUM L
INK
NATURE
OF SCIEN
CE –
INVESTIG
ATING IN
SCIENCE
EXTEND
THEIR EX
PERIENC
AND PER
ES
SONAL E
XPLANATI
OF THE N
ONS
ATURAL
WORLD
THROUG
H EXPLO
RATION,
PLAY, ASK
ING QUE
STIONS,
AND DISC
USSING
SIMPLE M
ODELS.
STARDOME.ORG.NZ
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