Unit Overview
Both the National Standards and the Benchmarks
emphasize concrete observations in teaching about “space
science” (astronomy) in elementary school, and they
de-emphasize in-depth explanations. This puts them in
some conflict with the state standards, which appear to
emphasize explanation. On the other hand, the astronomy
questions on the 4th grade ISAT exam do not
involve explanations (of seasons, moon phases, etc.) and
do, in fact, emphasize familiarity with the relative
positions and characteristics of the sun, moon, planets,
and stars; and the observable changes that signal
differences in seasons (change in the position of the
sun in the sky), etc. Therefore, the emphasis in this
unit is on the concepts defined by the national
standards and tested on the ISAT exam.
From the
Benchmarks for Science Literacy:
“In grades 3-5, students should begin to develop an
inventory of the variety of things in the universe.
Planets can be shown to be different from stars in two
essential ways—their appearance and their motion.
Learning the constellation names is not important in
itself. When students know that the star patterns stay
the same as they move across the sky (and gradually
shift with the seasons), they can then observe that the
planets change their position against the pattern of
stars.
Once students have looked
directly at the stars, moon, and planets, use can be
made of photographs of planets and their moons and of
various collections of stars to point out their variety
of size, appearance, and motion. No particular
educational value comes from memorizing their names or
counting them, although some students will enjoy doing
so. Nor should students invest much time in trying to
get the scale of distances firmly in mind. As to numbers
of stars in the universe, few children will have much of
an idea of what a billion is; thousands are enough of a
challenge. (At this stage, a billion means more than a
person could ever count one-at-a-time in an entire
lifetime.)
Students' grasp of many
of the ideas of the composition and magnitude of the
universe has to grow slowly over time. Moreover, in
spite of its common depiction, the sun-centered system
seriously conflicts with common intuition. Students may
need compelling reasons to really abandon their
earth-centered views. Unfortunately, some of the best
reasons are subtle and make sense only at a fairly high
level of sophistication.
Some ideas about light
and sight are prerequisite to understanding astronomical
phenomena. Children should learn early that a large
light source at a great distance looks like a small
light source that is much closer. This phenomenon should
be observed directly (and, if possible,
photographically) outside at night. How things are seen
by their reflected light is a difficult concept for
children at this age, but is probably necessary for them
to learn before phases of the moon will make sense.”
From the National Science Education
Standards:
“By observing the day and night sky regularly, children
in grades K-4 will learn to identify sequences of
changes and to look for patterns in these changes. As
they observe changes, such as the movement of an
object’s shadow during the course of a day, and the
positions of the sun and the moon, they will find the
patterns in these movements. They can draw the moon’s
shape for each evening on a calendar and then determine
the pattern in the shapes over several weeks.
These
understandings should be confined to observations,
descriptions, and finding patterns. Attempting to extend
this understanding into explanations using models will
be limited by the ability of young children to
understand that earth is spherical. They also have
little understanding of gravity and usually have
misconceptions about the properties of light that allow
us to see objects such as the moon. (Although children
will say they live on a ball, probing questions reveal
that their thinking may be very different.)” |
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Activity List
-
The
Universe—Overview and Introduction
-
Planetarium Visit; Observations and Journals
-
History
of Astronomy
-
Sun and
Earth: Apparent Movement of the Sun
-
Sun and
Earth: Shadows
-
Sun and
Earth: Orbit, Tilt, and Seasons
-
Earth
and Moon: Apparent Motion and Phases of the Moon
-
Eclipses
-
The
Solar System: Planets
-
The
Solar System: Planetesimals (optional)
-
Stars,
and Constellations
-
Student-Designed Investigations
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Learning Objectives
Students
will know and/or experience:
- The sun,
moon, stars, and clouds all have properties, locations, and
movements that can be observed and described.
- The
science of astronomy has been practiced by people for a long
time.
- Men and
women have made a variety of contributions throughout the
history of astronomy.
- The sun
appears to change position or move across the sky during
daylight hours.
- The
apparent movement of the sun is part of what defines our
sense of time, that is, defines our definition of a “day.”
- Shadows
formed by the sun will appear to move during the day in
correspondence with the movement of the sun in the sky.
- The shadow
of an object is always located on the side of the object
that is opposite the side of the sun or other light source.
- In
addition to spinning on its axis once every 24 hours, the
entire earth also moves in a circular path around the sun
(as do the other Solar System planets to be discussed
later). The amount of time that it takes for a planet to
make one full trip or orbit around the sun (i.e., return to
its starting place) is called one year.
- During the
one-year period that the earth orbits around the sun, there
are changes that take place in the climate at any one point
on the earth. These changes are repeated each year in a
pattern called the seasons.
- A very
important observable change that characterizes the seasons
is the length of time that the sun is in the sky and the
height that it reaches at mid-day. The sun is highest in the
sky—and the days are longest—in the summer, while the sun is
the lowest in the sky—and the days are shorter—in the
winter.*
- The moon
moves across the sky on a daily basis much like the sun. The
observable shape of the moon changes from day to day in a
cycle that lasts about a month.**
- The moon
has very different characteristics from the earth.***
-
Gravity is a force that holds us on the earth’s surface and
also holds the moon in orbit around the sun. The moon has
gravity as well (pulls on things), but it is much less than
on earth.
-
The earth is the
third planet from the sun in a system that includes the
moon, the sun, eight other planets, and their moons, and
smaller objects, such as asteroids and comets.
-
Like the earth, other planets have a
predictable orbit around the sun.
The amount of time that it takes
for a planet to make one full trip or orbit around the sun
(i.e., return to its starting place) is called one year.
Since each planet takes a different amount of time to make
one orbit, the length of a year is different on each planet.
- Each
planet has different characteristics; all other planets in
the solar system are very different from the earth.
-
Planets are held in orbit by the gravitational pull of the
sun; planets themselves also have varying amounts of
gravitational pull.
-
The order of the planets from the sun is: Mercury, Venus,
Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
- The Solar
System includes smaller objects, such as asteroids, comets,
meteors, and meteorites.
- Meteorites
give us clues to the origin and history of the solar system.
- Meteorites
may have been responsible for major changes on earth in the
distant past and may do so again in the future.
- Stars are
like the sun, some being smaller and some larger, but so far
away that they look like points of light.
- The
pattern of stars in the sky stays the same, although they
appear to move across the sky nightly and different stars
can be seen in different seasons.
* It is
ideal if the students make actual observations of this
phenomenon throughout the school year. If not observed, it
should be emphasized, as this is typically tested on the ISAT
(see sample questions at the end of the unit).
**Students at this grade
level are not expected to understand the explanation for why the
moon appears to change shape.
***Although none of the
standards for this grade level mention concepts related to the
characteristics of the moon and the planets, the ISAT exams do
test student knowledge of these characteristics. Therefore, this
content is included in this lesson and the next one.
Students
will practice*:
-
Formulating questions on a specific science topic and
choosing the steps needed to answer the questions
- Collecting
data for investigations using scientific process skills
including observing, estimating, and measuring
-
Constructing charts and visualizations to display data
- Using data
to produce reasonable explanations
- Reporting
and displaying the results of individual and group
investigations
*To
avoid repetition, these objectives are not listed in each
activity. Students practice one or more of these in virtually
all activities in the unit. |