Reasons
for Seasons
Exploring the Astronomy of Spring (a mini-unit)
Watching
the wave of spring sweep northward is at the heart of Journey North. Students
see seasonal changes all around them, yet these changes are all driven
by one underlying factor: changes in available sunlight.
This includes:
- the amount
of available sunlight (called day length 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.
Lesson |
Overview |
Exploring
Hourly Shadows and Sunlight |
This
slideshow inspires students to investigate shadows and sunlight outdoors
over the course of a day. Students begin to grasp what happens as
locations on earth move into and out of the sun's light each day. |
Exploring
Seasonal Shadows and Sunlight |
Students
measure shadows from fall through spring. They begin to understand
the relationship of sunlight, shadows, and seasons. This will help
them later grasp how the Earth's tilt on its axis influences these
phenomena. |
Following
the Sun for a Day |
Students create a simple model of the Earth and sun as seen from space.
They use it to explore the sun's apparent movement across the sky.
They begin to understand that the Earth's rotation toward the east
causes the sun to appear to move west each day. |
Following
the Sun Through the Year |
Students
create a simple model of the Earth and Sun as seen from space. They
use it to explore the apparent changes in the sun's angle (height
above the horizon) throughout a year. They begin to make connections
between the sun's angle in the sky, temperatures, and the seasons. |
Modeling
the Seasons |
Students
create 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. |
Heating
Up: Direct and Indirect Sunlight |
By
conducting simulations, students explore the effects of direct and
indirect sunlight on heating of the Earth. |
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. |
Note:
To
fully grasp what causes seasons, your students need a variety of opportunities
over time to explore light, shadows, and Earth-Sun models. These activities,
which require few materials, offer some basic strategies for getting started.
Visit the links below to dig deeper and find inquiries designed for different
grade levels.
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.
Assessment
Choose
from these tasks and tools
to document student understanding of key concepts in this mini-unit.
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