Welcome to Seasons ... Start
Seasons
Have you ever thought about why we have seasons?

Did you know that not all
parts of the Earth have seasons?

The reasons are quite complicated ... let's start
with some basics.
Are you sure you want
to leave this activity?
Yes No
Seasons
Earth
Sun
Not to scale
Here is a view from space, showing the Earth and the
Sun from above the North
Pole.

The diagram isn't to scale. In reality, the Earth is much smaller than the Sun and
much further away.

Use the animation controls to see how the Earth moves.
You can also select the Earth and move it to any position.
Are you sure you want
to leave this activity?
Yes No
Seasons
Earth
Sun
Not to scale
The path that the Earth takes as it moves around the Sun is called its orbit. The shape of the Earth's orbit is an ellipse, which is like a circle that is slightly stretched out.

Let's move to a different position in space.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
Earth
Sun
Not to scale
Now we're viewing the Earth from a different position, but it moves around the Sun in
the same orbit as before. We have a counter to measure how long it really takes for
the Earth to move once
around the Sun.

How long do you think it will take?
327 days
365 days
372 days
Use the animation controls and watch the Day counter
to find out.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 5
Earth
Sun
Not to scale
Correct!

It takes about 365 days for
one complete revolution.

This is the period of time we refer to as a year — the time
it takes the Earth to revolve once around the Sun.
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
Here is a closer view of the Earth. As it revolves around the Sun, the Earth moves in another way — it rotates.

The Earth rotates around an imaginary line that is tilted
at an angle that goes through the North and South Poles.
This is called the Earth's axis.
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
How long do you think it
takes for the Earth to complete one full rotation around its axis?
24 hours
12 hours
6 hours
Use the animation controls and watch the hours
counter to find out.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
Correct!

It takes 24 hours for the
Earth to complete one full
rotation — one day and one
night.

The combination of the Earth
orbiting the Sun and rotating
around its tilted axis affects
many things, such as seasons
and the length of day and
night.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
Here are two models. The
top one shows the Earth and the Sun together. The
bottom model shows a close-up view of the Earth rotating as it moves around the Sun.

Select A or B to view the
Earth from two different viewpoints as it rotates and moves along its orbital path. You can switch views at any time.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
Sun path
W
N
E
Melbourne
View from: Melbourne
As the Earth rotates, to a
fixed observer on the Earth,
the Sun appears to travel
across the sky from east to west.

This new diagram shows the apparent path of the Sun across the sky as viewed from Melbourne.

Look at where Melbourne is
on the Earth model when the Sun is rising in the lower diagram.

Use Rotate to see the Sun
rise and set.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
Sun path
W
N
E
Melbourne
View from: Melbourne
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
Sun path
W
N
E
Melbourne
Correct.

The Earth's rotation makes it appear as if the Sun is moving across the sky.

Since the Earth spins in an easterly direction, from a fixed point on the Earth, the Sun appears to rise in the east and set in the west.
View from: Melbourne
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
Sun path
W
N
E
W
N
E
S
Melbourne
View from: Melbourne View from: Melbourne
Here is another diagram showing the Sun's path.

To the observer in
Melbourne, the Sun appears
to move in an arc across the sky.

Use Rotate to see the Sun
rise and set.
Are you sure you want
to leave this activity?
Yes No
Seasons
1000 km
This diagram shows a beam
of the Sun's energy striking
the Earth north of the
equator.

At this point on the Earth's surface, it spreads over a circular area 1000 kilometres in diameter. It provides light and heat.

Select the beam of sunlight and move it up as far as you can, so that it strikes the
area at the North Pole.
Are you sure you want
to leave this activity?
Yes No
Seasons
1000 km
3600 km
Sunlight
Notice how the same beam
of energy from the Sun
strikes a much larger area
near the pole. Now it covers an oblong area of about 3600 kilometres.

This means that the Sun's
light and heat are spread
over a much larger area at
the poles. The result is less heating of the Earth's surface in these locations, so it is colder.
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
A
B
C
The Earth's atmosphere also affects how the Sun's energy reaches the Earth. Near the poles, the Sun's rays have to travel through more of the atmosphere, so more of their energy is reflected back into space.

Where on the Earth does the beam go through the
minimum amount of the atmosphere?
Location A
Location B
Location C
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
A
B
C
Correct!

The more directly overhead the Sun is, the less of the atmosphere its rays have to travel through. This means that the maximum amount of heat energy reaches the Earth at or near the equator.
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
A
B
C
Where does the beam move through the maximum
amount of the atmosphere?
Location A
Location B
Location C
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
0.0 hours
Earth's axis of rotation North Equator South
A
B
C
Correct!

The lower the Sun appears in the sky, the more of the atmosphere the beam has to travel through. This reflects more of its energy into space, reducing its heating effect.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
W
Y
X
Z
There are four locations marked on the Earth:

W is in the Arctic Ocean.
X is on the equator.
Y is near the equator.
Z is in Antarctica.

Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
W
Y
X
Z
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
W
0 ºC
Y
28 ºC
X
30 ºC
Z
–60 ºC
Correct!

The temperatures at the two locations near the equator (X and Y) are warmer than the locations near the North and South Poles.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
W
0 ºC
Y
28 ºC
X
30 ºC
Z
–60 ºC
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
W
0 ºC
Y
28 ºC
X
30 ºC
Z
–60 ºC
Correct!

Sunlight strikes the Earth at the poles at a much lower angle, therefore its energy is spread over a much greater area.

This reduces its heating
effect compared to near the equator, where the Sun can
be directly overhead, with its energy concentrated on a smaller area.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
A
B
Not to scale
1
2
3
4
Compared to the plane in which the Earth revolves around the Sun, the Earth's axis of rotation is tilted.

This means that at different times during the year, the northern or southern hemisphere is tilted towards the Sun.

In position 1 of this model,
the northern hemisphere is tilted towards the Sun.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
A
B
1
2
3
4
You can select the Earth in
the top diagram and move it
to different positions in its orbital path.

Now move it to the position where its southern
hemisphere is tilted towards the Sun.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
0.0 hours
View: A B
A
B
Rotate
play
Orbit
play
Correct!

When the Earth is in this position, the southern hemisphere is tilted towards the Sun.
Are you sure you want
to leave this activity?
Yes No
That's not it.

Australia is in the southern hemisphere. Look at the close-up view of the Earth and use Australia's position as a guide.
Try again
That's still not right.

Try moving the Earth to
position 3.
Try again
Seasons
Day 184
12.00 am
View: A B
Daylight: 14 hr 51 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Melbourne is in the southern hemisphere.

The View from Melbourne shows the apparent path of
the Sun across the sky as viewed from Melbourne.

Use Rotate to see the Sun
rise and set.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
12.00 am
View: A B
Daylight: 14 hr 51 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
When the Earth is at this position in its orbit, what season do you think it is in Melbourne?
Summer
Autumn
Winter
Spring
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
12.00 am
View: A B
Daylight: 14 hr 51 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Correct!

When the southern hemisphere is tilted towards the Sun, it is summer there.

The Sun is high in the sky, so it has a stronger heating effect. Also, more hours of daylight mean that heating occurs for a longer period.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
12.00 am
View: A B
Daylight: 9 hr 10 min
Melbourne
W
N
E
S
A
B
1
2
3
4
Rotate
play pause View from: Melbourne
Now move the Earth to a position along its orbit when
it is winter in Melbourne.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
12.00 am
View: A B
Daylight: 9 hr 9 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Orbit
play
Correct!

When the southern
hemisphere is tilted away
from the Sun, it is winter there.
Are you sure you want
to leave this activity?
Yes No
That's not it.

The Sun is high in the sky when
the Earth is tilted towards it.
What effect do you think that has on temperatures?
Try again
Incorrect.

Remember, the Sun is high in the sky, so it has a stronger heating effect.
Try again
That's still not right.

When the Earth is in this position
in its orbit, it is summer in Melbourne.
Try again
Seasons
Day 1
12.00 am
View: A B
Daylight: 9 hr 9 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Now look at the View from Melbourne.

Compared to its position in summer, would you say that
in winter the Sun is:
High in the sky
Low in the sky
Neither high nor low
You can use Back to review the Sun's position in
summer.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
12.00 am
View: A B
Daylight: 9 hr 9 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Orbit
play
Correct!

In this position, the southern hemisphere is tilted away from the Sun, which means the Sun appears low in the sky. There are also less hours of daylight. These things make it colder.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
0.0 hours
View: A B
A
B
1
2
3
4
Now move the Earth to a position in its orbit so that neither hemisphere is tilted towards the Sun.

Note that there are two
views of the Earth — A and B. You may need to check both views to confirm your choice.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 92
0.0 hours
View: A B
Correct!

At this position in its orbit, neither of the Earth's hemispheres is tilted towards the Sun.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 274
12.00 pm
View: A B
Daylight: 12 hr 0 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
At this position in the Earth's orbit, what season do you think it is in Melbourne?
Summer
Autumn
Winter
Spring
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 274
12.00 pm
View: A B
Daylight: 12 hr 0 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Correct!

The Earth is moving from a point where it was summer in the southern hemisphere to a point where it will be winter.

So at the position halfway in between, it is autumn in Melbourne.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 274
12.00 am
View: A B
Daylight: 9 hr 9 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Look at the View from Melbourne.

Compared to its position in summer and winter, would
you say that in autumn the
Sun is:
High in the sky
Low in the sky
Neither high nor low
You can use Back to review the Sun's position in
summer and winter.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 274
12.00 am
View: A B
Daylight: 9 hr 9 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Correct!

At this position in the Earth's orbit, the southern hemisphere is not tilted towards or away from the Sun. So during autumn in Melbourne, the Sun is neither high nor low in the sky.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
12.00 am
View: A B
Daylight: 9 hr 9 min
Melbourne
W
N
E
S
A
B
1
2
3
4
Rotate
play pause View from: Melbourne
Now move the Earth to the position in its orbit where it
is spring in Melbourne.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 92
12.00 am
View: A B
Daylight: 11 hr 57 min
Melbourne
W
N
E
S
Rotate
play pause View from: Melbourne
Correct!

The Earth is moving from a point where it was winter in the southern hemisphere to a point where it will be summer.

So at the position halfway in between, it is spring in Melbourne.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 1
5.30 am
View: A B
Daylight: 14 hr 51 min
Beijing
W
N
E
S
A
B
1
2
3
4
Rotate
play pause View from: Beijing
Here is a city in the northern hemisphere — Beijing.

Move the Earth to the
position in its orbit where it
is winter in Beijing.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
5.30 am
View: A B
Daylight: 9 hr 9 min
Beijing
W
N
E
S
Rotate
play pause View from: Beijing
Correct!

Beijing is in the northern hemisphere, which is tilted away from the Sun at this time of the year. So it is winter there.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
4.30 pm
View: A B
Daylight: 9 hr 9 min
Beijing
Melbourne
W
N
E
S
Rotate
play pause View from: Beijing
When it is winter in Beijing, what season is it in
Melbourne?
Summer
Autumn
Winter
Spring
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 184
4.30 pm
View: A B
Daylight: 9 hr 9 min
Beijing
Melbourne
W
N
E
S
Rotate
play pause View from: Beijing
Correct!

When one hemisphere is tilted towards the Sun, the other is tilted away. So when it is winter in one hemisphere, it is summer in the other.
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 2
6.30 am
View: A B
Daylight: 12 hr 0 min
Singapore
W
N
E
S
Rotate
play pause View from: Singapore
Here is another city, Singapore. It is almost right
on the equator.

At this position in the Earth's orbit, what season do you think it is in Singapore?
Summer
Winter
Neither of the above
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Day 2
6.30 am
View: A B
Daylight: 12 hr 0 min
Singapore
W
N
E
S
A
B
Rotate
play pause View from: Singapore
Correct!

Places near the equator do not experience much seasonal variation because the Sun is always high in the sky. This makes it warm to hot all year round.

The climate of places near the equator is affected more by prevailing winds, elevation and rainfall.
Are you sure you want
to leave this activity?
Yes No
Seasons
21 June
Now let's pretend the Earth's axis was not tilted. How do
you think that would affect
the seasons?

Move the Earth to the various positions in its orbit to investigate.

Which statement is correct?
The seasons are unaffected.
The seasons are reversed.
There are no seasons.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
21 June
Correct!

Without a tilted axis, neither hemisphere tilts either towards or away from the Sun at any time during the year. So seasons would not exist.
Are you sure you want
to leave this activity?
Yes No
Seasons
1.30 am
View: A B
Daylight: 9 hr 9 min Add
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui
Rotate
play pause View from:  Wanganui
Wanganui in New Zealand has
a latitude of approximately
40 south.

The View from Wanganui
shows the apparent path of
the Sun across the sky as viewed from Wanganui in
June.

Use Rotate to see the Sun moving across the sky.
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: 9 hr 9 min Add
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui
Rotate
play pause View from:  Wanganui
The Daylight counter shows approximately how many
hours of daylight Wanganui experiences on a given day.

Use Orbit to change the date and you will see the duration of daylight change.

Select Add to put the hours
of daylight in the table.
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: 9 hr 9 min Add
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui
Rotate
play pause View from:  Wanganui
Use the arrows on either side of the date to move the
Earth forward or backward a day at a time.

Selecting Add will replace
the data in your table from
the previous setting.
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: 9 hr 9 min Add
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui
Rotate
play pause View from:  Wanganui
Move the Earth to the first date in the calendar year
when there are
approximately 12 hours of daylight in Wanganui.

Use the date and orbit controls, and look at the Daylight counter to help you find the correct date.

Select Add to complete the table, then select Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: 9 hr 9 min Add
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui
Rotate
play pause View from:  Wanganui
Good work.

Now find another position in the Earth's orbit when the
day in Wanganui is approximately 12 hours long.

Select Add to complete the table, then select Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
5.30 pm
View: A B
Daylight: Add
W
N
E
S
21 September
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Rotate
play pause View from:  
Excellent.

The two 12-hour days in Wanganui occur on 21 March and 21 September.
Are you sure you want
to leave this activity?
Yes No
That's not it.

Watch the Daylight counter for Wanganui as you try the Earth in different positions around the
Sun.

Make sure you select the second date in the calendar year on
which a day in Wanganui is 12 hours long.
Try again
That's still not right.

Move the Earth so that the date is 21 September.
Try again
Seasons
8.00 pm
View: A B
Daylight: 9 hr 9 min Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing
Rotate
play pause View from:  Beijing
Beijing, China, has a latitude of about 40 north.

There are two days a year when there are
approximately 12 hours of daylight in Beijing.

Move the Earth to the
position in its orbit when it is the first time in the year this occurs.

Select Add to complete the table, then select Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: 9 hr 9 min Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing
Rotate
play pause View from:  Beijing
Good work.

That is one of the dates
when the day is
approximately 12 hours long
in Beijing.

Now move the Earth to another time of the year
when the day in Beijing is
12 hours long.

Select Add to complete the table, then select Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 September
A
B
Location Date Daylight
Wanganui 31 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Rotate
play pause View from:  
Correct!

Did you notice that the two
12-hour days in Wanganui are the same dates as the two
12-hour days in Beijing —
21 March and 21 September?

The dates when day and
night have equal length are called the equinoxes, and
they can vary by a day or so from year to year.
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Rotate
play View from:  
Orbit
play
Wanganui and Beijing are not the only cities to have approximately 12 hours of daylight on the equinoxes.
This is also the case in other cities as well.

In fact, give or take a few minutes, on these two days,
no matter where you are in
the world, the day is about
12 hours long.
Are you sure you want
to leave this activity?
Yes No
Seasons
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Rotate
play pause View from:  
Each year there are two equinoxes, when day and
night are equal length.

Why do you think the equinoxes happen at these
two points in the Earth's orbit around the Sun?

Because the Earth's axis is:
Tilted neither away from nor towards the Sun
Tilted towards the Sun
Tilted away from the Sun
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
21 March
0.0 hours
View: A B
Correct!

On the equinoxes, the tilt of the Earth's axis isn't away
from or towards the Sun, so the southern and northern hemispheres receive equal amounts of daylight.

Check View A and you will
see that the day/night boundary is in line with the axis at this position.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Daylight: 9 hr 9 min Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui
Rotate
play pause View from:  Wanganui
Now move the Earth to the position when there are the least hours of daylight in Wanganui.

Select Add to complete the table, then select Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Rotate
play View from:  
Orbit
play
Correct!

The shortest day of the year
in Wanganui is 21 June.
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Rotate
play View from:  
Orbit
play
The shortest day of the year
in Wanganui (approximately
9 hours and 9 minutes) is also the shortest day in other places in the southern hemisphere.

This is because:
Neither hemisphere tilts towards or away from the Sun.
The southern hemisphere tilts away from the Sun.
The southern hemisphere tilts towards the Sun.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Rotate
play View from:  
Orbit
play
Correct!

When the southern hemisphere is tilted away from the Sun, it has less time to receive daylight and warmth as the Earth rotates.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Daylight: 9 hr 9 min Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing
Rotate
play pause View from:  Beijing
Approximately how long is
the day in Beijing on
21 June?
9 hours and 9 minutes
12 hours
14 hours and 51 minutes
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
8.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Rotate
play View from:  
Orbit
play
Correct!

On this day, there are about
14 hours and 51 minutes of daylight.
Are you sure you want
to leave this activity?
Yes No
Seasons
4.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Rotate
play View from:  
Orbit
play
Beijing is the same latitude north of the equator as Wanganui is south of the equator. However, it has
much longer days around
21 June.

This is because:
Neither hemisphere tilts towards or away from the Sun.
The northern hemisphere tilts away from the Sun.
The northern hemisphere tilts towards the Sun.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
4.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Rotate
play View from:  
Orbit
play
Correct!

When the northern
hemisphere is tilted towards the Sun, it has more time to receive daylight and warmth
as the Earth rotates.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Daylight: 9 hr 9 min Add
Beijing
Wanganui
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Wanganui
Rotate
play pause View from:  Wanganui
Now move the Earth to the position when there are the most hours of daylight in Wanganui.

Select Add to complete the table, then select Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
4.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 December
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Wanganui 21 Dec 14 hr 51 min
Rotate
play View from:  
Orbit
play
Correct!

The longest day of the year
in Wanganui (approximately
15 hours) is 21 December. It
is also the longest day in
other places in the southern hemisphere.
Are you sure you want
to leave this activity?
Yes No
Seasons
4.00 pm
View: A B
Daylight: Add
Beijing
Wanganui
W
N
E
S
21 December
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Wanganui 21 Dec 14 hr 51 min
Rotate
play View from:  
Orbit
play
Are you sure you want
to leave this activity?
Yes No
Seasons
4.00 pm
View: A B
Daylight: Add
Beijing
W
N
E
S
21 December
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Wanganui 21 Dec 14 hr 51 min
Rotate
play View from:  
Orbit
play
Correct!

When the southern hemisphere is tilted towards the Sun, it has more time to receive daylight and warmth as the Earth rotates.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Daylight: 9 hr 9 min Add
Beijing
Wanganui
W
N
E
S
21 December
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 12 hr 0 min
Beijing 21 June 14 hr 51 min
Wanganui 21 Dec 14 hr 51 min
Beijing
Rotate
play pause View from:  Beijing
So approximately how long
do you think a day is in
Beijing on 21 December?
9 hours and 9 minutes
12 hours
14 hours and 51 minutes
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Daylight: Add
W
N
E
S
21 June
A
B
Location Date Daylight
Wanganui 21 Mar 12 hr 0 min
Wanganui 21 Sept 12 hr 0 min
Beijing 21 Mar 12 hr 0 min
Beijing 21 Sept 12 hr 0 min
Wanganui 21 June 9 hr 9 min
Beijing 21 June 14 hr 51 min
Wanganui 21 Dec 14 hr 51 min
Beijing 21 Dec 9 hr 9 min
Rotate
play View from:  
Orbit
play
Correct!

The shortest day in Beijing is about the same length as the shortest day in Wanganui.

Because Wanganui and
Beijing are the same distance from the equator (40 south
and 40 north), both their shortest and longest days are the same lengths. However, they occur six months apart because they are in different hemispheres.
Are you sure you want
to leave this activity?
Yes No
Seasons
21 June
Beijing
Wanganui
Now let's pretend the Earth's axis was not tilted.

How do you think this would affect the length of the days
at these locations at
different times of the year?
The length of the days would be unaffected.
The days would be approximately 12 hours long everywhere, all the time.
The days would be shorter in winter and longer in summer.
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
21 June
Beijing
Wanganui
Correct!

Without a tilted axis, neither hemisphere would lean either towards or away from the Sun at any time of the year.

So everywhere on Earth would face towards the Sun for 12 hours and away from the Sun for 12 hours, every day of the year.
Are you sure you want
to leave this activity?
Yes No
Seasons
90° North Equator  0° 90° South 60° 30° 60° 30°
The latitude of a location is
an angular measure, in degrees, north or south of
the equator.

The equator has a latitude of 0. The South Pole has a latitude of 90 south.

In this activity, you will investigate what effect latitude has on daylight hours in different locations.
That's not it.

The Sun's rays travel a smaller distance through the Earth's atmosphere at another location.
Try again
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Cairns
W
N
E
S
21 June
A
B
Location Date Daylight
Cairns
Rotate
play pause View from:  Cairns
In this view, the location of Cairns is shown on the Earth.

The View from Cairns shows the apparent path of the Sun across the sky as viewed from Cairns in June.

Use Rotate to see the Sun
rise and set.

When you are ready, select Calculate daylight hours for this location.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Cairns
W
N
E
S
21 June
A
B
Location Date Daylight
Cairns
Rotate
play pause View from:  Cairns
Use Orbit to change the
date, and you will see the
path of the Sun appears to change.

When you're ready, select Calculate daylight hours to
get a new reading.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Cairns
W
N
E
S
21 June
A
B
Location Date Daylight
Cairns
Rotate
play pause View from:  Cairns
Use the arrows on either side of the date to move the
Earth forward and backward
a day at a time.

Select Calculate daylight
hours
to replace your data in the table.
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Cairns
W
N
E
S
21 June
A
B
Location Date Daylight
Cairns
Rotate
play pause View from:  Cairns
Approximately how many daylight hours does Cairns experience on
21 December?

Move the Earth to the
position in its orbit when it is 21 December.

Select Calculate daylight hours, then Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
12.00 am
View: A B
Cairns
W
N
E
S
21 June
A
B
Location Date Daylight
Cairns 21 Dec 13 hr 0 min
Rotate
play View from:  Cairns
Orbit
play
Correct!

On 21 December, Cairns gets about 13 hours of daylight.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  Kisumu
Now there are four locations marked on the globe.

Kisumu, Kenya is almost
   right on the equator, at
   0 latitude.


Cairns, Australia has a    latitude of approximately
   17 south.


Wanganui, New Zealand
   has a latitude of
   40 south.


The Mawson Antarctic Base
   is located at a latitude of
   67.5 south.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  Kisumu
Move the Earth to the
position in its orbit when it is 21 March.

Select a location in the
table.

Then use Calculate daylight hours to add the data to the table.

Repeat this process for each location, then Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Well done.

You've found that the length
of the day on 21 March at all four locations is the same — approximately 12 hours.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  Kisumu
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Correct!

On 21 March, all locations on the Earth experience approximately 12 hours of daylight.
Are you sure you want
to leave this activity?
Yes No
Seasons
21 March
0.0 hours
View: A B
Look at the Earth's axis. Compared to the plane of the Earth's orbit, it is tilted.

Use the diagrams to find out
if, on 21 March, the Earth's axis is:
Tilted towards the Sun
Tilted away from the Sun
Neither tilted towards nor away from the Sun
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
21 March
0.0 hours
View: A B
Orbit
play
Correct!

The tilt of the Earth's axis is neither towards nor away from the Sun on 21 March.
Are you sure you want
to leave this activity?
Yes No
Seasons
21 March
0.0 hours
View: A B
A
B
Orbit
play
In this position, the tilt of
the Earth's axis is neither towards nor away from the Sun.

So all locations receive light from the Sun for half of the
24 hours it takes the Earth to rotate around its axis.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  Kisumu
Now the Earth is in the position of its orbit on
21 June.

Do you think these four locations will have the same daylight hours on 21 June?

Select a location in the
table, then use Calculate daylight hours to add the
data to the table.

Repeat this process for each location, then select
Submit table.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Kisumu has approximately
12 hours of daylight, but all the other day lengths are different.

This is because the daylight hours depend on the latitude of the location:
Only on 21 June
At most times during the year
Every day of the year
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Correct!

At most times of the year, the length of the day depends on the latitude of the location. However, you've already found that this isn't the case on 21 March.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Look at the Earth's axis
again.

On 21 June, which
hemisphere is tilted towards the Sun?
The southern hemisphere
The northern hemisphere
Neither hemisphere
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Correct!

Because of the tilt of the Earth's axis, the northern hemisphere is tilted towards the Sun on 21 June.

This means that the southern hemisphere is tilted away from the Sun, so it doesn't receive as much daylight as on 21 March.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  
Orbit
play
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Correct!

In the southern hemisphere at this time of year, places near the equator (low latitudes) receive the most light as the Earth rotates on its tilted axis.

Places at very high latitudes, such as the Mawson Antarctic Base, receive no light.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
On 21 June, places in the southern hemisphere experience their shortest day of the year. The shorter days at this time of year mean
that the Sun has less time to heat the southern parts of
the Earth.

This is one reason why it is colder during winter.

But the main reason is that, where it's winter, the Sun's
rays hit the planet at a
shallow angle. This means their energy is spread more thinly over a larger area, and the temperature is lower.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  Kisumu
Find the position in the
Earth's orbit where places in the southern hemisphere experience their longest day
of the year and complete the table for that date.
Submit table
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Good work.

On 21 December, places in
the southern hemisphere experience their longest day
of the year.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Look at the Earth's axis. On
21 December, which hemisphere is tilted towards the Sun?
The southern hemisphere
The northern hemisphere
Neither hemisphere
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play View from:  
Orbit
play
Correct!

Because of the tilt of the Earth's axis, in December the southern hemisphere is tilted towards the Sun.

This means it is summer,
when locations in the
southern hemisphere receive their maximum amount of daylight.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play play View from:  
Orbit
play
Seasons
Rotate
play View from:  
Orbit
play
Correct!

At this time of year, places in the southern hemisphere
with very high latitudes, such as the Mawson Antarctic
Base, receive 24 hours of daylight as the Earth rotates on its tilted axis.

Places near the equator receive slightly more than
12 hours.
Are you sure you want
to leave this activity?
Yes No
Seasons
Rotate
play pause View from:  Kisumu
Now complete the table for each location on
21 September.
Submit table
Are you sure you want
to leave this activity?
Yes No
That's not it.

Make sure all the day lengths are for 21 September.
Try again
That's still not it.

The incorrect answers have been removed from the table.
Try again
That still wasn't right.

These are the correct answers.
OK
Seasons
Rotate
play View from:  
Orbit
play
Good work.

You've found another date (21 September) when the length of the day at all four locations is the same.
Are you sure you want
to leave this activity?
Yes No
Seasons
21 September
0.0 hours
View: A B
A
B
Orbit
play
On 21 September, which hemisphere is tilted towards the Sun?
The southern hemisphere
The northern hemisphere
Neither hemisphere
Submit
Are you sure you want
to leave this activity?
Yes No
Seasons
21 September
0.0 hours
View: A B
A
B
Orbit
play
Correct!

Just like on 21 March, neither hemisphere is tilted towards the Sun on this date, so all locations receive light for half of the 24 hours it takes the Earth to rotate around its axis.
Are you sure you want
to leave this activity?
Yes No