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Reasons
for Seasons
Exploring the Astronomy of the Seasons
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Mini-Unit—
To fully
grasp what causes seasons, students need a variety of opportunities over
time to explore light, shadows, and Earth-Sun models. The five activities
in this mini-unit require few materials and offer some basic strategies
for exploration. You can use them sequentially or individually to reinforce
or lay the groundwork for your students' online investigations of seasonal
change.
Watching
seasonal change is at the heart of Journey North. Students observe evidence
of seasonal change all around them, yet all of these changes are driven
by one underlying factor: changes in available sunlight.
This includes:
- the amount
of available sunlight (called daylength or photoperiod)
- the sun's
intensity (related to the
angle at which it strikes the Earth).
Mini-Unit
Objectives
These background lessons are designed to reinforce or
lay the groundwork for your students' Journey North studies. The lessons
can be used sequentially or individually. After this series of lessons,
students in grades 4-8 should be able to:
- Model
the tilt of the Earth as it orbits the Sun.
- Understand
the meaning and characteristics of solstices and equinoxes.
- Understand
that sunlight hits the Earth at different angles at different locations
over the course of a year and that this affects temperatures.
- Explain
what causes seasonal changes.
Activity |
Overview |
1.
Exploring Shadows and Sunlight |
By measuring
changes in shadows over time, students notice daily and seasonal patterns. |
2.
Following the Sun |
Students
use a simple model of the Earth and Sun as seen from space to explore
the sun's apparent movement across the sky over the course of a day
and year. |
3.
Modeling the Seasons |
Students
explore a model of the Earth’s daily rotation and annual revolution
around the sun; they try to puzzle out at which point each season
occurs in their part of the world. |
4.
Heating Up: Direct and Indirect Sunlight |
By conducting
simulations, students explore the effects of direct and indirect sunlight
on heating of the Earth. |
5.
Sunrise, Sunset, and Seasons |
Students
track photoperiod (daylight hours) over time, predict how daylight
will change during different seasons, and use this to enhance their
understanding of seasonal change. |
Laying
the Groundwork for This Unit
Younger
Students
- Ask students
to create a list of things they see, do, and feel during different seasons.
Ask, How do these things change from season to season? Do any of
these relate to the environment (e.g., temperature changes)? Describe
how. (E.g., You can ice skate because it’s cold enough for
water to freeze; robins come back because it’s warmer.) What
do you think causes these changes?
- Generate
list of questions raised by this exercise and use it as a springboard
for some of this mini-unit's activities.
Older
Students
- Ask students
to try to characterize the different seasons by discussing weather,
appearance of living things, human activities, and so on. Ask, What
do you think causes each of these changes?
- Invite
students to share what they know about the reasons for seasons.
- Generate
a class list of things they’re unsure of and questions they have.
Use these as a springboard for some this mini-unit's activities.
Related
Links
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