Download Educator`s Guide for Dark Star Adventure

Dear Educator,
Welcome to the “DarkStar Adventure” planetarium show Teacher’s Guide! Produced by
Spitz Creative Media, DarkStar Adventure takes the audience on an unforgettable voyage
of discovery through the cosmos. This guide contains content and spectacular activities to
support your planetarium show experience. We encourage you to do as many of these
activities as possible before your trip so your students can better understand the concepts
in the show.
The guide contains three main sections:
1. Gravity In and Out
2. Bright Stars Tonight
3. DarkStar Dead Ahead
Gravity In and Out has fun activities related to Newton’s Law of Motion, escape velocity,
and rocketry. Bright Stars Tonight focuses on what we see in the night sky and its meaning.
DarkStar Dead Ahead looks at the role gravity plays in the lives of stars, particularly in the
development of black holes. All activities are directly related to phenomena your students
will experience in the show.
Each section has content pages to help you with the background of each activity. In
addition, there are black line masters, where needed, to support the activities. While most
of the acitvities are correlated to the National Science Education Standards for grades 5-8,
you’ll find activities appropriate for elementary and senior grades as well.
Enjoy your trip through the universe!
Spitz, Inc.
2
Table of Contents
Description of DarkStar Adventure Planetarium Show
3
Gravity In and Out
4
Escape Velocity: Discover how to get off the planet
5
Escape Velocity Rocket: Make your own classroom rockets
6
Bright Stars Tonight
7
Star Observations: Help students enjoy the wonder of star observation
8
Star Colors: Observe color changes as temperature rises
9
Star Distances: Examine enormous distances between us and stars
10
Are We There Yet?
11
Are We There Yet? Worksheet
12
DarkStar Dead Ahead
13
Stellar Evolution: Study the forces that make stars collapse
14
Shock Waves: See shock waves produced after supernova explosions
15
Black Holes: Experience the large gravitational force of black holes
16
DarkStar Adventure Planetarium Trip Sheet
18
Glossary and Suggested Resources
19
Description of DarkStar Adventure
Subrah is a mischievous teenage girl who is bored by science. She’s stuck with her father on a distant planet
as he studies a nearby star at the end of its life. The impending supernova forces Subrah and her father
to quickly abandon the planet, but an accident launches Subrah’s father into space without her! Subrah
draws on her science knowledge to explore pulsars, dodge black holes, and harness magnetic fields with
her trusty robot friend Sweeps until she is reunited with her father. She’s still not safe though; Subrah
needs to come up with one more brilliant and dangerous scheme before they can go home to planet Bekenel.
3
GRAVITY IN AND OUT
What is Gravity?
Isaac Newton was the first to describe gravity as an ‘attractive’ force associated with mass. We know it as
the force that seems to ‘pull’ objects together or make things fall to the floor or ground. Every object in
the universe that has mass, has gravity. Newton figured that the more massive an object is, the greater its
gravitational pull. Here’s an astronomical example: How much do you weigh? 150 pounds? The moon is
one-quarter the size of Earth and has a gravitational pull one-sixth that of Earth. So on the moon you’ll
weigh just 25 pounds. Think of it as instant weight loss!
Proximity also plays a role in gravitational attraction. As distance increases, gravitational pull decreases.
Since Earth itself is more massive than anything on it, all things on the Earth are being pulled to it.
Since our sun is the most massive object in the solar system, everything in our solar system is being
pulled towards it.
For more information about gravity, check out
http://www.sunblock99.org.uk/sb99/people/RWalsh/gravity/grav1.html
http://brp.arc.nasa.gov/Science/Y_GBL/bsc_resrch.html
Newton’s Cannon
EARTH
Escape Velocity – Speed needed to escape an object’s gravitational pull.
Imagine a cannon on top of a mountain, its barrel pointed toward the horizon.
When the cannon is fired, the cannonball, after traveling some distance, will fall
to the ground. Fired with more force, the cannonball may travel farther, but
gravity will eventually pull the cannonball to rest on the ground. If the cannonball can be launched with enough velocity, instead of falling back to earth it will
continuously fall around the earth!
The circular path described by a projectile falling
around the earth is called an orbit. For a rocket
to escape Earth’s gravitational pull, it needs to
travel fast enough to reach escape velocity – the
speed at which an object will leave the Earth’s
gravitational influence. An object launched at
low speeds will eventually fall back to Earth.
DARKSTAR ADVENTURE CONNECTION: Subrah must
escape impending doom by propelling her ship to a
high enough escape velocity to leave a planet.
For more information about escape velocity, check out:
http://quest/arc/nasa.gov/space/teachers/microgravity/3world.html
Launching Rockets
For rockets to fly off into space, they obey Newton’s Third Law: For every action, there is an equal and
opposite reaction. Our homemade rockets (page 8) illustrate this: air pressure inside the rockets builds and
pushes equally on all sides of the interior; when pressure is high enough, the stopper is pushed out, air pushes
out the opening but is still pushing against the inside of the rocket. As Newton’s Third Law states (see
Appendix A), the force of air pressure pushing inside the rocket must be equal to the force of the exhaust
pushing out the opening. It is the force inside the rocket that pushes it in a direction opposite the exhaust.
DARKSTAR ADVENTURE CONNECTION: When stuck, Subrah cleverly tows a useless ship along
and ejects it at the right moment and in the right direction, applying Newton’s third law; the
abandoned ship goes off in one direction, pushing her off in the right (opposite) direction.
4
ESCAPE VELOCITY
Objective:
Understand escape velocity by observing a ball drop.
National Science Education Standards:
Physical Science: Motions and forces
Earth and Space Science: Earth in the solar system
Materials:
Ball, table, chart paper
Things to Discuss Before:
Ask students how we launch rockets into outer space.
How fast is the rocket traveling?
Why do students think the rocket needs to travel so fast?
Things to Do:
1. On the floor, lay out a 10-foot strip of chart paper, trailing away from the edge of a table.
2. Bring a ball to the edge of that table and let the ball drop. Have students notice the path and
landing point of the ball (it should fall directly below the edge of the table) on the chart paper.
3. Push the ball so that it slowly rolls across the table and let it drop. Have students notice the path
and landing point of the ball (it should fall in a curved path and land further away from the table)
on the chart paper.
4. Push the ball harder so it rolls faster and observe what happens. Repeat at higher and higher speeds.
Things to Discuss After:
Ask students what they noticed and have them draw diagrams of their observations. Ask students what
would happen if you rolled the ball at even higher speeds and draw a diagram. Discuss why the ball keeps
dropping down (gravity). Draw a circle to represent Earth and draw a ball above. Ask students what path
the ball would take if it traveled very fast. Draw, and then repeat with the ball traveling at higher speeds
until ball orbits Earth. Explain that ball is actually falling towards Earth (due to gravity), but its high speed
prevents it from ever reaching the ground. Ask children what would happen if ball was traveling even
faster; it would escape Earth’s gravity and leave orbit. This speed is the escape velocity.
Extensions:
• Attach a ball to the end of a rope and swing in circles to represent the ball orbiting around Earth.
Pretend it is traveling fast enough to escape Earth’s gravity and let go.
• Have two students toss a ball to each other and back up until they are throwing the ball over a long
distance. What do students notice about the arc of the ball as distance increases? How about the
speed and required force? Can they imagine how much more speed and force is needed to launch
a rocket?
5
Escape Velocity Rocket
Objective:
Discover how rockets work by making your own.
National Science Education Standards:
Science as Inquiry: Design and conduct a scientific investigation and make the relationships between
evidence and explanations
Science and Technology: Abilities of technological design
Materials:
15 ml conical tubes with rubber stoppers to fit (enough for every one to four students), Alka-Seltzer
tablets (two per group), water, droppers, small trays.
Notes:
1. The 15 ml tubes can also be replaced with clear plastic 35mm film canisters with tightly fitting lids.
The film canisters must be the clear plastic ones, not grey or black.
2. You can use vinegar and baking soda in place of Alka-Seltzer and water.
3. These rockets can hit the ceiling. You may want to launch rockets from the floor or outside.
Things to Discuss Before:
Throw a ball up. Ask students how you can make it go higher. How
do you have to change your force or your speed? Is it possible it to
go higher without increasing speed? Explain that students are going
to make their own rockets and must figure out how to make them
go as high as possible. Their rocket fuel is limited, so they need
to budget carefully as they launch.
Have students practice capping
and standing tubes up without AlkaSeltzer; injuries can happen if the
rockets fly sideways instead of up.
Rocket Gas Explanation: In both rockets, the gas
produced is carbon dioxide. In the Alka-Seltzer,
the gas is released through the reaction of the
sodium bicarbonate and citric acid of the AlkaSeltzer tablet when water is added. Carbon
dioxide is released from the baking soda/vinegar
mixture when the acetic acid of the vinegar reacts
with the sodium bicarbonate of the baking soda.
Things to Do:
1. Have students put a couple squirts of water in tubes.
2. Have students break off a very small chunk of Alka-Seltzer
(less than the diameter of a pencil eraser).
3. Quickly put Alka-Seltzer in tubes, cap with stoppers, invert
tubes and place on trays, let go, and stand back.
4. Observe what happens inside the rockets and note how high rockets fly.
5. Let students experiment to figure out how to make rockets fly higher.
Things to Discuss After:
How did students make their rockets fly high? Why did their rockets fly? How much more force and speed
would they need to launch their rockets into outer space?
Extensions:
• Modify rockets with fins.
• Hold a challenge to see who can launch the highest rocket.
• Keep track on data sheets amount of water and Alka-Seltzer used in each trial. Experiment and
discover optimal mix of ingredients and technique.
• Make other types of rockets. Try the ones at these websites:
http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/other/liquid_bottle_rocket.html
http://www.calstatela.edu/dept/chem/chem2/LACTE/K12.html
6
Bright Stars Tonight
Star Colors
We usually think of stars as twinkling white, but if we look carefully we can actually find stars of several
colors. A star’s color is based on its temperature. A very cool star is dull red in color. As stellar temperatures
increase the colors change from red to orange, then yellow to white, and then blue.
These different colors relate to the star’s “thermal radiation.” As temperatures increase, the wavelength
of the emitted thermal radiation shortens, and the colors change.
Star Observations
It may seem challenging to observe stars, but all it takes to get started is a good pair of eyes. Star maps
(easily obtainable from the Internet or from you local library) and binoculars can help too, but your students
can enjoy astronomy without them.
You may want to start your students off with quick, five-minute glimpses at the sky to spot some easy-tofind reference points. Can they find the moon? What does it look like? How about planets or stars of
different colors? Some easy to find constellations include the Big Dipper, the Summer Triangle, the Great
Square of Pegasus, and Orion (visible during the school year).
As your students become more comfortable with the night sky, you can expand your search to include
binary stars, nebulae, fainter constellations, and other fascinating or ephemeral phenomena such as lunar
eclipses. You may even want to contact your local astronomy club to hold a star party for your grade or
your school. Often, astronomy clubs enjoy providing telescopic views of various astronomical objects for
free. This exposes your students to a new hobby; children may want to continue their astronomy observations
by attending club meetings. Parents are curious about the night sky too. Take advantage of their curiousity
to get them more involved in helping their children observe!
“Astronomy for Kids” http://www.dustbunny.com/afk/ has wonderful
information about constellations and tips for beginning sky watchers.
For some good basic tips on astronomy observations,
check out http://www.stargazing.net/david/eyes/index.html
7
Star Observations
Objective:
Examine the patterns and characteristics of stars through observations.
National Science Education Standards:
Earth and Space Science: Earth in the solar system
Materials:
Blank paper, colored pencils
Things to Discuss Before:
Ask children what objects they see in the night sky and list them.
Things to Do:
1. From either a classroom window or an outside play or recess area, help students identify different
parts of the sky.
a. Horizon – distant horizontal line where the sky meets the ground;
b. Zenith – point at the top of the sky directly overhead;
c. Nadir – point directly opposite the zenith - under your feet;
d. Meridian – imaginary vertical line running head to toe that when extended to the sky
directly ahead of you divides the eastern half of the sky from the western half.
2. Have children practice drawing what they see out toward the horizon from the horizon up to their
zenith. Then have children practice doing night sky observational drawing in the classroom; have
them pick an area of the room and draw what they see from the “horizon” (the floor) and up,
including the ceiling. You may want to hang pictures of stars and the moon around the room.
3. For homework, have children choose an area of sky to observe. Starting from the horizon, have
them draw everything they see, including objects at the horizon, bright stars, different colored stars
(using colored pencils), and the moon in the correct phase.
4. Repeat the exercise for several nights, observing and drawing the same part of the sky.
Things to Discuss After:
What did children notice during their observations? What patterns do they see?
Extensions:
• Discuss patterns the stars make, and introduce constellations. Have kids find basic constellations
in the sky (such as the Big Dipper, Orion, Pegasus or Leo).
• Look for meteor showers.
Use this link to find what’s available http://dustbunny.com/afk/skywonders/meteorshower/
• Encourage students to look
at night sky with binoculars.
You can find good, basic sky maps and observing information for beginners at
• Take your students on a
http://skyandtelescope.com/howto/basics/article_1100_1.asp
field trip to a local observatory.
For star maps for kids, go to http://www.dustbunny.com/afk
For detailed sky maps unique to your location and time, check out http://www.fourmilab.to/yoursky/
8
Star Colors
Objective:
Observe color changes as objects are heated, and understand that stars are also different colors
National Science Education Standards:
Physical Science: Transfer of Energy
Materials:
Objects that change color as they are heated and heat sources (see below), candles or Bunsen Burners
Things to Discuss Before:
Ask students what they know about star colors and what they have observed.
Things to Do:
1. Show students an object that changes color as it is heated and discuss what may be happening.
2. Have students observe candle flames or Bunsen burner flames (can also demo with propane torch)
and hypothesize about the temperatures of the different parts of the flames.
Things to Discuss After:
What can students say about colors and heat?
How does that relate to stars?
Extensions:
• Encourage students to go outside and look for different colors of stars.
Color changing objects as heated:
1. Incandescent light bulb turned on and off slowly with a dimmer switch.
2. Electric burner or hotplate on stove that is heated and cooled
Just as we can tell temperatures of objects here on Earth by their color,
so can we tell the temperature of stars in space. Here’s a guide to help
you easily identify star temperatures.
6000ºF
9000ºF
11000ºF
15000ºF
20000ºF
Bunsen burner, candle, and
propane torch flames have a
blue cone surrounded by orange.
For more information about flame colors and star colors check out these websites:
http://webexhibits.org/causesofcolor/3B.html
http://www.straightdope.com/mailbag/mhotflame.html
http://www.mira.org/fts0/stars/114/txt001w.htm
http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml
http://www.kidsastronomy.com/stars.htm
http://www.astronomycafe.net/qadir/q72.html
9
Star Distances
Distances in space are so vast that ‘miles’ are too small. To measure such vast distances we have to use
bigger ‘rulers.’ One way astronomers have found to measure the enormous distances in space is to use
“light speed” to describe them. Here’s an example: our own Sun is 93,000,000 miles away. Since light travels at 186,000 miles per second, the light from our Sun takes 8 minutes to reach Earth. When we look up in
the sky, we are not seeing the Sun as it is now, but as it was in the past 8 minutes ago!
Other stars are so far away that we use light years to describe them. A light year is the distance light travels
in one year. Since light travels at 186,000 miles per second, one light year is almost 6 trillion miles! The
nearest star, Proxima Centauri, is 4.2 light years away. Aldebaran, one of the brightest stars in our sky,
is 68 light years away. Therefore, when we look up in the sky at night, we are actually seeing stars as they
used to be, not as they are now. You could also describe this as looking back in time.
TABLE OF 20 BRIGHTEST STARS
Star
Name
Distance
(light years)
Brightness
(sun=1)
The Sun
Proxima
Beta Centauri 526
Procyon
Altair
Fomalhaut
Sirius
Pollux
Vega
Arcturus
Capella
Aldebaran
Achernar
Canopus
Spica
Alpha Crucis
Antares
Betelgeuse
Rigel
Deneb
-4.4
526
11
17
23
8.6
35
26
35
46
68
130
120
260
260
420
522
800
1600
1
1.5
5.5
7
11
15
23
33
53
100
160
170
830
2100
2300
3000
5700
10000
47000
67000
DARKSTAR ADVENTURE
CONNECTION: Subrah
must grapple with very
large distances as she
tries to get back home.
Source: Ottewell, Guy, 2003, To Know the Stars, Universal Workshop, Middleburg, VA; Observer’s Handbook 2004;
Gupta, Rajiv, Ed.; The Royal Astronomical Society of Canada, Toronto, University of Toronto Press, 2003
Notes:
1. Light Year – distance traveled in one year at the speed of light(186,000mph). A distance of nearly 6 trillion miles.
2. Brightness – How bright these stars are relative to our sun; the sun represents a brightness unit of 1.
10
Are We There Yet?
Objective:
Help students understand the vastness of space and distance of stars.
National Science Education Standards:
Earth and Space Science: Earth in the solar system
Materials:
“Are We There Yet?” worksheets, calculators
Things to Discuss Before:
Ask students how long they think it would take to go to the sun. Explain that even at the speed of light,
it takes 8 minutes to travel between the Earth and the Sun; therefore, we are seeing the sun as it was in
the past. If the sun explodes, we won’t know it until 8 minutes later! Ask students to guess how old the
light is from stars.
Things to Do:
1. Demonstrate the math necessary to do the worksheet on the following page.
2. Have kids fill out worksheets to calculate how long it takes to get to other orbiting bodies by
probe, telescopes, rovers, shuttles, and light.
Things to Discuss After:
What did students notice about the age of the light from stars? Were they surprised? Explain that we are
looking at stars as they were many years ago, not as they are now.
11
Are We There Yet?
Name: ___________________________________________________________
Calculate how long it takes to get to other stars. For example, Proxima Centauri is 25,000,000,000 miles
away from Earth. Therefore, to calculate how long its light takes to reach Earth, we would divide its
distance by the speed of light: 25,000,000,000,000 miles / 670,616,600 mph = 37,279 hours/24 hours
per day = 1553 days/365 days per year = 4.2 years
Star distance
from Earth
CAR
speed = 50 mph
SHUTTLE
speed = 17,000 mph
LIGHT
speed = 670,616,600 mph
Moon 239,000 miles
4.2 years
Sun 93,000,000 miles
Proxima Centauri:
25,000,000,000,000
miles
DISTANCES AROUND THE UNIVERSE
Venus average
26 million miles
Mars average
50 million miles
Pluto
3.6 billion miles
Polaris/North Star
431 ly
Orion Nebula
1500 ly
Center of Our Galaxy (the Milky Way)
50000 ly
Closest Galaxy – Large Magellanic Cloud
165,000 ly
Closest Spiral Galaxy – Andromeda Galaxy
2.9 million ly
Closest Black Hole – V4641 Sagittari
1600 ly
Closest Quasar
1 billion ly
Edge of the Observable Universe
13-15 billion ly
12
DarkStar Dead Ahead
The lives of stars are governed by gravity. Gravity causes clouds of gas and dust to collapse and form
new stars. A star will shine for perhaps billions of years as fusion reactions in its core change hydrogen to
helium. The core is always pushing outward, trying to expand, but is held in check by the surrounding large
gaseous envelope pressing inward due to gravity. Now a “main sequence” star, it shines at a steady rate.
Our Sun is a main sequence star.
This equilibrium lasts until the core runs out of energy and can no longer push outwards. In very massive
stars much bigger than our sun, exciting events rapidly happen. The core suddenly collapses. The gaseous
envelope collapses with the core, sucked in by gravity, but suddenly “bounces” off the core. The gases
shoot out into space in shock waves as the star explodes in a supernova.
While the gases explode outwards, the core collapses in on itself and becomes a very tight, small, and dense
ball of matter called a neutron star. This neutron star has such a strong magnetic field that it concentrates
light and radiation into cones, much like a double ended flashlight. It also rotates like a lighthouse beam.
The combination of the strong magnetic field and very rapid rotation creates a pulsar, a “flashing star”.
DarkStar Adventure Connection: An exploding supernova
and its shockwaves force Subrah to flee a planet. She
then collects oxygen for her ship from a pulsar nebula.
For more information about the life of stars check out these websites and books:
http://map.gsfc.nasa.gov/m_uni/uni_101stars.html
http://www.geocities.com/thesciencefiles/astar/isborn.html
http://imagine.gsfc.nasa.gov/docs/teachers/lessons/xray_spectra/background-lifecycles.html
http://nrumiano.free.fr/Eindex.html
http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle/
http://imagine.gsfc.nasa.gov/docs/teachers/lifecycles/LC_main_p1.html
Jarvis, Seth and Jarvis, Nathan Y., Lifestyles of the Big and Powerful, 1991, Capstone Press,
Chicago, dist. By Children’s Press, ISBN: 1560650117
13
Stellar Evolution
Objective:
Understand that massive stars explode as a result of collapsing cores.
National Science Education Standards:
Earth and Space Science: Earth in the solar system
Materials:
No special materials needed
Things to Discuss Before:
Explain that stars evolve as a result of gravity. When stars are at a steady state, like our sun, the core and
the gaseous envelope around the core have equal gravities; they push on each other equally. When star
cores run out of energy, however, the gravity forces become unequal.
Things to Do:
1. Have two equal sized students stand up and push against each other. There should be equilibrium,
or no movement. Ask students what is going on.
2. Swap one student for a much smaller one. Explain that the smaller student represents a star’s core
after it has run out of energy. Now have the students push against each other.
Things to Discuss After:
Discuss what happened in the demonstration. Why do stars collapse?
Extensions:
• Invite an astronomy club to hold a star party at your school to look for the remnants of exploded
stars. These are called nebulae.
• Search the Hubble Space Telescope website for images and descriptions of nebulae and
supernovae remnants. http://hubblesite.org/gallery/
14
Shock Waves
Objective:
Discover why shock waves are produced after supernova explosions.
National Science Education Standards:
Earth and Space Science: Earth in the solar system
Materials:
Small ball, big ball, shallow trays, water, eyedroppers
Things to Discuss Before:
Explain that very massive stars (bigger than our sun) at the end of their lives will explode in a supernova.
When the star’s core runs out of fuel, it collapses dramatically.
Things to Do:
1. Place a small ball on top of a big ball.
2. Hold balls about a yard off the ground, drop, and observe what happens (the small ball will
bounce much higher than the big ball). Explain that the small ball represents gas bouncing off the
core of the sun, or the big ball. The gas explodes into space.
3. Set out trays of water. Have students use eyedroppers to drip drops of water in the middle of the
trays. Observe rings of waves.
Things to Discuss After:
What do students notice about the rings of water? How do they move?
Explain that the rings of water represent shock waves, or the waves of gas produced by supernovas.
The core of the sun is shrinking, and the gaseous envelope
follows it (represented by the balls dropping). Eventually
the gas bounces off the core (represented by the large
bounce of the small ball).
All our heavy elements, from Iron to Lawrencium
including the precious metals gold and silver, are
produced in supernova explosions. The high-energy
explosions smash atoms together forming small
quantities of rare elements.
For more information check out these websites:
http://imagine.gsfc.nasa.gov/docs/teachers/lessons/xray_spectra/background-elements.html
http://aether.lbl.gov/www/tour/elements/stellar/stellar_a.html
15
Black Holes
A black hole is what’s left over after a big star (at least three times the size of our Sun) explodes in a
supernova at the end of its life. The leftover atomic nuclei collapse and condense together, compacting
and becoming more and more tightly packed. The result, a black hole, is an object of very high mass and
very high gravitational force: so strong that its escape velocity is higher than the speed of light. Except
under very special circumstances, nothing, not even light, can escape from a black hole.
Most popular descriptions of black holes use Newton’s concepts of gravitation to help people understand
their behavior. Unfortunately, in the case of strong gravity or speeds approaching the speed of light, (two
of the main features of black holes) Newton’s principles of gravitation fail miserably. Newton himself was
aware of his theory’s failings at those extremes. Einstein’s general theory of relatively far more accurately
describes gravitation as the geometry of the 4-dimensional spacetime within which everything in the
universe exists.
Visualizing 4-D spacetime is difficult since common sense can’t help us create that view. A crude model
using a flexible piece of stretchy fabric and a few manageable masses like sport balls may work.
In the following demo, we use a horizontally stretched piece of jersey to represent space and time. The
jersey flexes when we put objects on it, which represents the gravitational forces. A light, less massive
object bends the jersey very little and has little gravitational force. A more massive object makes a deep
depression in the jersey and has large gravitational force. The massive object represents a black hole.
A small object will roll towards the depression and fall, illustrating the enormous gravitational attraction
of the black hole.
For more information about black holes, visit
http://www.geocities.com/thesciencefiles/black/holes.html
DARKSTAR ADVENTURE CONNECTION: Subrah lands on
a planet that is being torn apart by a nearby black hole. She
needs to launch off the planet at a high enough escape velocity
to break away from the gravitational pull of the black hole—
which requires double emergency thrust!
16
Black Holes
Objective: Observe a model of the large gravity force exhibited by black holes.
National Science Education Standards:
Earth and Space Science: Earth in the solar system
Materials:
Old T-shirts or pieces of jersey (preferably black), cardboard boxes, scissors, tape, balls of various sizes
and densities (marbles, small and large steel balls – balls of different masses)
Things to Discuss Before:
Explain that when a really big star (three times the size of our Sun) is at the end of its life, it explodes in a
supernova, then collapses. The remains of the star become packed together and very dense, creating a
black hole. Objects with large masses, like the Earth, have strong gravity forces. Black holes have enormous masses in a small area, so they have extremely strong gravity forces. Not even light escapes, so anything close to black holes is trapped. Explain that students will create models where the fabric represents
what Einstein called spacetime. The bending of the fabric represents gravity.
Things to Do:
1. In groups, have students cut the T-shirt or jersey into a flat sheet and stretch and tape it over
an open end of box.
2. Place a small ball on the fabric and observe what happens.
3. Replace the ball with a larger, more massive ball.
4. Add other balls to the sheet and observe how they roll.
Things to Discuss After:
What did students notice?
How does the massive ball affect the spacetime fabric sheet?
How about the lighter balls?
How is the massive ball like a black hole?
Try other black hole/spacetime exercises at:
http://www.ktca.org/newtons/11/blckhole.html
You can also do this as a demo. Cut a large, flat piece of
jersey. Have two children hold the fabric taut horizontally.
Have other students place balls on the fabric.
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DARKSTAR ADVENTURE PLANETARIUM SHOW Trip Sheet
Name: ___________________________________________________________
1. When do you think Subrah was the most resourceful and creative in solving a problem? Why?
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2. What is your favorite scene in the show? Why?
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3. Draw a supernova, pulsar nebula, or a black hole.
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Glossary
Atomic nuclei
Black hole
Escape velocity
Light year
Mass
Magnetic field
Neutron star
Pulsar
Spacetime
Supernova
Velocity
Appendix A
Newton’s Three Laws of Motion
1. An object in motion will stay in motion. An object at rest will stay at rest.
2. Force equals mass times acceleration.
3. For every action there is an equal and opposite reaction.
See http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html for more information.
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