Teacher
:
So
you've
got
a
few
minutes
to
discuss
with
your
partner
.
Student
1
:
So
,
as
as
I
know
,
the
main
similarity
between
Mars
and
Earth
is
that
they
can
both
support
human
life
.
Student
2
:
Yeah
,
but
do
we
that's
actually
true
?
I
mean
,
Mars
is
much
colder
than
Earth
,
it
?
It
says
here
it's
about
minus
55
degrees
most
of
the
time
,
whereas
on
Earth
only
places
like
Antarctica
get
that
cold
.
Student
1
:
True
.
Well
then
,
I
you
could
say
both
planets
are
a
similar
distance
from
the
Sun
?
Student
2
:
No
way
!
Mars
is
much
further
away
!
It
here
it's
about
228
million
kilometres
,
while
Earth
is
about
150
million
.
Student
1
:
Yes
,
but
in
space
that's
that
far
.
Jupiter
is
,
like
,
almost
780
million
kilometres
.
That's
why
we
astronomical
units
when
we
talk
about
distances
in
space
.
Earth
is
1
astronomical
unit
from
the
Sun
and
Mars
is
1
.
3
.
The
difference
doesn't
sound
so
big
when
you
look
at
it
that
way
.
Student
2
:
I
see
what
you
.
Jupiter
is
5
.
2
astronomical
units
so
I
guess
you're
right
.
What
other
similarities
are
there
between
the
two
planets
?
Student
1
:
Let's
?
not
the
colour
,
obviously
!
Student
2
:
Yeah
!
Earth
is
the
blue
planet
and
Mars
is
called
the
red
planet
for
pretty
obvious
reasons
!
Student
1
:
Their
sizes
are
pretty
different
.
Mars
is
about
half
the
size
of
Earth
.
Student
2
:
What
about
this
?
It
like
the
days
on
both
planets
are
almost
the
same
length
.
Earth's
day
is
24
hours
but
Mars's
is
about
half
an
hour
longer
.
Student
1
:
right
.
OK
,
any
other
things
they
both
share
?
Student
2
:
I
suppose
you
could
say
they
have
water
in
common
.
Student
1
:
you
?
How
?
Student
2
:
Well
,
Earth
is
70
per
cent
water
and
Mars
probably
had
huge
oceans
in
the
past
.
It's
just
that
most
of
the
water
there
now
is
probably
frozen
.
Student
1
:
Ah
,
I
see
.
I
don't
we
can
say
the
air
is
the
same
,
though
.
Most
of
Earth's
air
is
nitrogen
and
oxygen
,
but
Mars
?
?
Student
2
:
Mars
really
have
air
,
not
compared
with
Earth
.
It's
got
about
one
per
cent
as
much
air
as
Earth
.
Student
1
:
Right
,
and
it's
mostly
carbon
dioxide
.
Student
2
:
Gravity
is
another
difference
.
I
know
this
,
but
Mars
has
higher
gravity
than
the
Moon
.
But
it's
much
less
than
on
Earth
,
of
course
.
Student
1
:
Oh
,
yes
.
It
says
Mars
about
38
per
cent
of
Earth's
gravity
.
Teacher
:
OK
,
let's
see
what
you've
found
?