8561RB AC Science Year 6 revised edition LR watermark

Earth and space sciences
Lesson 3
Why do we have seasons?
Content focus:
Science inquiry:
Patterns of change related to Earth’s tilt, rotation and revolution
Planning and conducting | Processing, modelling and analysing | Evaluating | Communicating
Background information
• Earth orbits the Sun on its tilted axis of 23.5 degrees from
the vertical, giving us seasons. When the southern (bottom)
part of Earth is facing the Sun, it is summer in the south.
Approximately six months later, the southern part of Earth is
facing away from the Sun, giving that part of Earth winter.
• The tilt causes some areas of Earth to experience slanting rays
of sunlight for part of the year and more direct rays of sunlight
at other times.
• In summer, the Sun appears higher in the sky. The length of the
shadows change throughout summer and winter, because of
the Sun’s differing height in the sky.
Preparation
• Students will require the following equipment for the
investigation on page 39: black paper; thermometer; torch;
ruler; sticky tape, white crayon.
The lesson
• Pages 37 and 38 are to be used together.
• Before reading the text, discuss with the class what they know
about seasons. Once the four seasons have been discussed,
ask the class why we have seasons. Read through the text to
clarify the answer.
• Students work in small groups to complete the experiment,
measuring and recording the temperature of the thermometer
when the torch is directly above and when it is at an angle.
The experiment could be done by measuring an angle of
23.5 degrees from the vertical, to mimic the tilt of Earth,
but the temperature results may not be as significant to
demonstrate the effects of a tilt.
• Discuss each group’s experiment results. Record them as
a table on the board. How does this relate to why we have
seasons? Remind the students that Earth’s axis is on a tilt of
23.5 degrees from the vertical.
• Ask students to consider how they could conduct another
activity that focuses on demonstrating the seasons
in Antarctica.
Do any of your students find it challenging to work
in groups?
Consider having them assign each member of their group a
role (e.g. leader, notetaker, reporter, help seeker) during the
‘Demonstrating the reason for seasons’ activity.
Answers
Page 38
1.
summer
winter
autumn
spring
Measure in a minute
spring
autumn
winter
summer
2. Earth is tilted at an angle, so some of its parts are tilted
further towards the Sun than others. The parts of Earth that
receive more sunlight are warmer and experience summer.
The opposite parts of Earth receive less sunlight, making them
colder, which is when they experience winter.
3. (a) winter (b) summer
4. True
5. There are only two seasons in Antarctica.
6. It is still cold because the Sun that reaches Antarctica is not as
strong or as warm, due to the low-lying angle of Antarctica.
7. The polar night relates to Antarctica’s winter sky, which is
almost always dark from March to October.
Page 39
Teacher check: The experiment should demonstrate a reduced
temperature, as well as a light that is less intense and more
spread out, when the torch is at an angle. This is similar to how
the tilt of Earth affects the intensity of sunlight that it receives in
different parts.
© R.I.C. Publications
Low resolution display copy
Give each student a small whiteboard and marker, and ask
them to draw and label how Earth moves and experiences
seasons.
36 Australian Curriculum Science (Year 6) 978-1-923005-13-6 R.I.C. Publications ® ricpublications.com.au