FROM A DISTANCE. . .
OBJECTIVES:
After completing the pre-activity worksheet, experiencing the StarLab
presentation, and completing the extension activities, students will have a good
understanding of the vastness of the universe and the concept of light years.
RELATION
TO MISSOURI FRAMEWORKS:
Science
Frameworks
9-12:
VA1 The
current model of the universe was developed from evidence about its content and
theoretical assumptions based upon mathematical and computer-simulated models
9-12:
VA3 Because
of the vast distances between objects in the universe, light may take billions
of years to reach Earth.
Math
Frameworks
9-12:
I1
Problem-solving strategies such as organizing data, drawing a picture,
looking for a pattern, modeling, researching, and algebraic strategies.
9-12:
II2
Mathematical ideas may be represented with visual models.
9-12:
IV2
Mathematics is used in other subjects.
9-12:
IV3
Mathematics is used in the real world.
Earth
Science Curriculum
This lesson fits into the beginning of the astronomy unit.
It exposes, or
reviews,
some common terms and concepts of astronomy to lead into the concept of light
years. Light years will be studied
to help students understand the great distances between objects in the universe,
which accounts for the fact that it takes billions of years for light to reach
earth in many instances.
CONTEXT:
Grade level: 9-12
Group of 15-25 for StarLab presentation
PREREQUISITE:
Students should have completed the pre-activity worksheet that goes along
with this StarLab presentation.
MATERIALS:
StarLab Portable Planetarium
Starfield Cylinder
Solar System & Galaxy Cylinder
Arrow pointer
Red flashlight (for reading)
PROCEDURE:
1.
After all students are seated and
ready, turn off side lamps to allow their eyes to adjust to the dark.
2.
While sitting in the dark, review the
rules of the StarLab and discuss safety procedures in case of a power failure.
“If we must exit quickly, move to the center of the dome and sit
quietly. I will fold the dome,
which takes about five seconds, and we will then be able to move to the
bleachers or exit the building, depending on what is needed.
3.
Introduce the activity with these
questions: “What is astronomy?”
[Branch of science dedicated to the study of everything in the universe
that lies above Earth’s atmosphere.] “What
is a planetarium?” [A domed room
and a planetarium projector, a device that realistically represents the sky from
any place on Earth and any point in time.]
4.
Set the Starfield cylinder to 37
degrees latitude and today’s date at 9:00 p.m.
Turn on projector. Give the
students a minute to “be amazed.” Ask,
“What is a constellation?” [Grouping
of stars.]
5.
Use the pointer to point out some
common constellations and stars that are visible.
[Big Dipper, Polaris, Little Dipper, Draco the dragon, Cygnus the swan
(Northern Cross), Cepheus the king, and Cassiopeia the queen.]
Ask, “Will the stars stay in this position all night?”
[No. The stars appear to
move across the sky from East to West.]
6.
Turn on the rotator. Remind students that although it appears as though the stars
are moving, they are not. The Earth
is rotating on its axis, which creates the illusion that the stars are moving
through the night sky.
7.
Stop the rotator at 3:00 a.m.
Again, point out some common constellations to illustrate that the stars
change position in the night sky.
8.
Discuss with students that although the
stars appear as just tiny specks of light, through space exploration,
mathematical models, and computer-simulated models, astronomers now have a
better understanding of stars. Ask,
“What is a star?” [A glowing
ball of gas held together by its own gravity and powered by nuclear fusion in
its core.] Ask, “What is the name
of the star closest to Earth?” [The
Sun.]
9.
Ask, “What is the solar system?”
[The Sun and all the bodies that orbit it—Mercury, Venus, Earth, Mars,
Jupiter, Saturn, Uranus, Neptune, Pluto, their moons, the asteroids, and the
comets.] Review with students that
the Earth, along with the other planets, revolves around the Sun.
10.
Turn down projector light, and change
to the Solar System cylinder. Take
the cover off of the top to show the Milky Way Galaxy, but leave on the side
cover at this time. Place the
projector at 90 degrees latitude. While
it is still dark, ask, “What is a galaxy?”
[A gravitationally bound collection of a large number of stars.]
Ask, “What is the name of our galaxy?”
[The Milky Way Galaxy.]
11.
Turn on the projector to show the Milky
Way Galaxy. Point out that our
galaxy is 50,000 light years wide. Ask,
“What is a light year?” [The
distance that light can travel in 1 year. Equal
to 9.46 trillion kilometers or 5.88 trillion miles.]
12.
Inform the students that to calculate
the distance across the galaxy, you would take 9.46 trillion km times 50,000 or
5.88 trillion miles times 50,000, depending on what unit is desired.
However, the time needed for light to travel from one side of the galaxy
to the other is given. If the distance is 50,000 light years, then it takes 50,000
years for light to travel from one side of the galaxy to the other.
13.
Turn down projector light.
Take off the side cover of the cylinder.
Place the projector at 37 degrees latitude.
Turn on the projector.
14.
Point out the Sun and planets of our
solar system. Explain that the size
scale shows the relative size of the Sun and planets. Explain that the distance scale shows the relative distance
between the Sun and planets.
15.
Point out that Earth is about 93
million miles from the Sun. That is
equal to 0.000016 light years (1.6 x 10 e-5).
It would take light 8 minutes and 20 seconds to travel from the Sun to
the Earth.
16.
Point out that Pluto is about 3.7
billion miles, on average, from the Sun. (Discuss
that Pluto’s orbit is elongated, making its distance from the Sun vary a great
deal.) That is equal to 0.00069
light years (6.9 x 10 e-4). It
would take light 5 hours, 26 minutes, and 18 seconds, approximately, for light
to travel from the Sun to Pluto.
17.
Tell the students that the time needed
for light to travel from the Sun to Pluto is about 40 times longer than the time
needed for light to travel from the Sun to Earth.
18.
Conclude the presentation by explaining
that we will set up our own distance scale of the solar system during the next
class session. We will also
calculate the distance in light years between the Sun to each planet and the
time it takes for light to travel from the Sun to each planet.
REFERENCES:
A Manual for Using Portable Planetariums by Gerald L. Mallon, EdD.
The Regents of the University of California.
1993.
Astronomy Today by Eric Chaisson and Steve McMillan.
Prentice-Hall, Inc. 1999.
Earth Science Activities for the Elementary Classroom (KSAM),
Level 4-6. Edited by Ernest L.
Kern, PhD. Curriculum
Associates, Inc. 1997.
The Cosmic
Perspective by Jeffrey Bennett, Megan Donahue,
Nicholas Schneider, and Mark Voit. Addison
Wesley Longman. 1999.
EXTENSIONS
AND/OR ADAPTATIONS:
During the next day’s class period, complete the “How Far is Far”
KSAM activity along with the Light Year Worksheet.
CONTENT
BACKGROUND:
Looking into the night sky, we often observe the stars and the moon,
giving little thought to the distance from here to there.
In fact, most people probably don’t even comprehend the vastness of
this universe! However, the fact remains that our universe is truly
“astronomical” in size. Just
our Milky Way Galaxy is 4.73 x 10 e17 kilometers wide, or 2.94 x 10 e17 miles
across. In regular notation, that
number would look like this: 294,000,000,000,000,000
miles!
Obviously, using this size of numbers to talk about the stars, planets,
and galaxies would be almost unbearable, so scientists created the unit called
the light year. A
light year is defined as the distance light can travel in one year.
One light year is equal to 9.46 trillion kilometers or 5.88 million
miles.
APPENDIX:
“How Far is Far?” KSAM activity sheets
FROM A DISTANCE. . .
1.
What is astronomy?
2.
What is a planetarium?
3.
What is a constellation?
4.
What is a star?
5.
What is the name of the star closest to
Earth?
6.
What is the solar system?
7.
What is a galaxy?
8.
What is the name of our galaxy?
9. What is a
light year?
FROM A DISTANCE. . .
Distance in light years =
Distance from the Sun in kilometers
9,460,000,000,000
km/light year
Time needed for light to =
Distance from the Sun in kilometers
travel from the Sun to
Speed of light
that planet
(in seconds)
(Speed of light =
300,000 km/s)
Distance from
Time needed for light
Sun in
to travel from the
Light
years Sun to the planet
Sun
Mercury
Venus
Earth
Mars
Asteroids
Jupiter
Saturn
Uranus
Neptune
Pluto
Moon
Alpha
Centauri