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SCIENCE FROM SOJOURNER, THE MARS ROVER
MASTER TEACHER Katherine Price
GRADES 9-12
OVERVIEW AND BACKGROUND
On July 4, 1997, NASA's Pathfinder landed on the Ares Vallis
region of Mars. Pathfinder carried a rover called Sojourner, named after
the abolitionist Sojourner Truth. Ares Vallis was chosen as a landing site
because it is thought to be an enormous ancient outwash plain -- a large region
over which many floods occurred in the early history of Mars. Such a site
had a good chance of yielding a variety of surface materials carried from
distant sources (upstream), and was relatively "safe" for a rover to
explore (no cliffs to fall off or very steep slopes to climb). This
portion of the Live from Mars series shows interviews with several scientists
who explain what, in their opinion, were the important findings of the
Pathfinder mission.
This lesson may take up to five class sessions, and will help
students to develop critical listening skills, graphing and graph analysis
skills, and elementary principles of image interpretation used in planetary
surface mapping.
ITV SERIES
Passport to Knowledge: Live from Mars: Program 4 - Destination
Mars
LEARNING OBJECTIVES
Students will be able to:
* elaborate on Earth-Mars comparisons derived from graphs
* critically evaluate the words of scientists
* describe some of the important scientific results of the
Pathfinder mission
* construct a surface map of a portion of Mars
VOCABULARY
Pathfinder - lander mission to Mars, landed on 4 July
1997
Sojourner - rover on the Pathfinder mission
APXS - Alpha Proton X-Ray Spectrometer, an instrument on
Sojourner to determine chemistry of surface materials
Ares Vallis - presumed fluvial outwash plain chosen for
the Pathfinder landing site
analog - something that is analogous or similar to
something else; in planetary science we look for features on Earth
(terrestrial analogs) that are similar to those seen on other planets
datum - the "zero" elevation on Mars;
because there is no sea level, a zero level had to be identified
differentiated - zoned or divided into different regions,
as the Earth is differentiated into crust, mantle and core
Viking missions - NASA missions to Mars included orbiters
and landers in the 1970s
mosaic - images are pieced together to form a larger
image, or mosaic
pixel - a shortened word for "picture element",
which is the smallest resolved unit in an image. Nothing smaller that the
pixel size can be seen on the image.
resolution - a measure of the detail shown on an image.
Usually expressed in a unit of length (meters, kilometers or miles) per pixel,
such as 1.8 km/pixel.
MATERIALS
For each student:
2 sheets of graph paper
pencil
Atmospheric Comparisons: Earth and Mars worksheet
Focus for Viewing handout
For each group:
transparency for creating map
transparency pens - one of each of at least 3 different colors
clear tape or paper clips
global map of Mars:
An Explorer's Guide to Mars.
40" x 26" poster #505. $6.00 each.
vendor:
The Planetary Society - Sales Dept.
65 North Catalina Avenue
Pasadena, CA 91106-2301
phone: (626) 793-1675
fax: (800) 966-7827
e-mail: http://planetary.org
PRE-VIEWING ACTIVITIES
Planetary atmospheres may be described in terms of pressure or
density. Examine the data on the Atmospheric Comparisons: Earth and
Mars worksheet. Discuss the data ranges, and determine appropriate scales
for graphing the data. Plot, then compare and contrast atmospheric
pressure and density profiles for Earth and Mars.
FOCUS FOR VIEWING
Distribute Focus for Viewing sheets, one to each student.
Tell students that questions about each video segment are grouped as Segments,
so they will focus on the first set of questions during the first video Segment
A. To give students a specific responsibility while viewing, before
viewing each segment, ask a student to volunteer to read aloud the questions for
that segment so that students will know what they are to watch for. At
each indicated pause point, allow students to work in pairs to check for
understanding the questions for that segment. If necessary, rewind and
replay the segment before continuing.
Segment A
Advance tape to MVP (Most Valuable Picture) introduction by
Valerie Sill (sp?) holding a basketball. Tell students that there were
many successes associated with the Pathfinder mission to Mars, and the wonderful
images were just one of the successes. Each scientist has a favorite
choice for MVP (Most Valuable Picture). Ask a student to read the Focus
for Viewing questions for Segment A. Begin Segment A. Pause
after Donna Shirley says, "that's why this is a very valuable picture; it's
unique". Video is of Sojourner next to a rock (Barnacle Bill).
Ask students to work in pairs to check for correct and complete answers to the
Focus for Viewing questions.
Segment B
Tell students that, because Earth and Mars are two of the four
rocky, or terrestrial planets (Mercury, Venus, Earth and Mars), scientists are
not surprised to find both similarities and differences between the two planets.
The next segment, "Marvelous Mars" shows some of the similarities and
differences related to volcanoes, weather, land area, and the presence of life
on Earth and Mars. Ask a student to read the questions under Segment B on
their Focus for Viewing sheet. Resume "Marvelous Mars" to look
for Earth-Mars comparisons. Pause after the narrator says, "Mars, at
least on the surface and in modern times, is lifeless". Video is of
computer-simulated flyover of the martian surface. Pairs check answers to
questions for Segment B.
Segment C
Remind students that scientists are all human and all have
different personalities; that means that some may be easier to understand
than others. Segment C shows three scientists responding to different
questions. Ask a student to read the questions under Segment C on their
Focus for Viewing sheet. Ask students to be thinking about which scientist
answers the questions most clearly and directly. Resume tape. Pause
after Joy Crisp says, "we may be breaking up that old idea".
Pairs work together to check answers. Encourage
discussion of these questions: "Which scientist do you think is most
clear and easy to understand? Why? Rephrase, or translate into your
own words, the responses of the scientists. What did you NOT understand?
What else would you like to know from these scientists?" Ask students
to support their opinions -- students need not come to agreement. Rewind
and review the segment if needed.
Segment D
Fast forward a short distance to "the most recent press
conference". Video shows a blonde asking a question about what are
the important things have we learned from Pathfinder. Tell students that
they will be watching Matt Golombek talking about four major findings from
Pathfinder. Pause after Golombek says, "And finally, the barometer is
rising - it's starting to get cold - plan for autumn on Mars." Pairs
work together to check answers.
Segment E
The last segment shows Matt Golombek -- this time he is
speculating what it would be like if we could be on the surface of Mars without
a space suit. Tell students that we will view this segment first without
taking notes, and then we will view it again to take notes. Resume tape.
Pause where Matt concludes, "being on the surface; a place where you
can actually imagine, and that's kinda fun". Rewind to beginning of
the Segment E. This time, ask students to write down adjectives and
images used in Matt's description of how he imagines the Mars surface
environment. Stop at the same place as before. Rewind and
replay segment if necessary.
POST-VIEWING ACTIVITIES
Create a map of a portion of Mars. The purpose of this
exercise is to develop a map of Mars surface features in order to determine the
relative sequence of events in a particular area.
Examine the global map of Mars to determine the general area
you would like to map. Make careful note of your location relative to
other large features on Mars.
Visit the PDS (Planetary Data System) Mars Explorer for the
Armchair Astronaut website:
http://www-pdsimage.wr.usgs.gov/PDS/public/mapmaker/mapmkr.htm
Generate your base map (the black and white image on which you
will overlay a map) from the global index map on the PDS website by clicking on
your area of interest. You can zoom in or out, or pan to find an
interesting area. Look for an area which contains craters, channels, and
perhaps volcanoes, mountains or islands. If your original choice looks
uninteresting, try another location. When you have a mosaic image you
like, print it out. Recognize that these mosaics are all assembled from
Viking images. Beginning in mid-1999, images will become available from
the Mars Global Surveyor mission.
Clip or tape the transparency to the base map.
Determine the resolution, scale, and the latitude and longitude range of your
map using the image statistics at the bottom of your printout. The image
size is given as the number of rows and columns of pixels, and the pixel size is
also given. So, if your image size is 500 rows (of pixels) by 500 columns
(of pixels), and the resolution is 1.8 km/pixel, then the image is 500 x 1.8 =
277.8 km on a side. Draw a scale bar on your map -- you will have to
figure out how many km on the Mars surface are represented by a centimeter on
your map. Label the latitude and longitude extents of your map (also found
in the image statistics section). Draw a north arrow on your map.
Decide on a color scheme for your map symbols. Use the
colored transparency pens to outline crater rims, crater ejecta (the material
splashed out of the crater on impact), channels, islands, and other features you
can identify. Create a small legend to explain your color and symbol
scheme.
Write a summary of the geologic history of your area.
Consider these questions: Which events are oldest, intermediate, and
youngest? How do you know? Why do some crater rims appear to be more
eroded than others? What caused the difference in crater size? Is
water still present on the surface?
(This activity is modified from Destination: Mars Activity
Packet, 1977, NASA JSC, Houston, Lesson 4. If you prefer, you may
implement their lesson plan, which can be found at: http://cass.jsc.nasa.gov/expmars/channels.html)
ACTION PLAN
Visit these and other linked web sites once each week, and keep
a journal of new findings from the next mission, Surveyor.
The TES (Thermal Emission Spectrometer Project) from Arizona
State University.
http://esther.la.asu.edu/asu_tes/
Mike Malin's camera is on the Surveyor. New images are
posted on the Malin Space Sciences Systems site.
http://barsoom.msss.com/
EXTENSIONS
English
Imagine there are intelligent inhabitants on Mars who wonder
what Earth is like. Describe for them what it is like to be on Earth.
Create your own message using a medium of your choice. For example, you
may use words in the form of an essay or poem, choreograph and perform a dance,
use any of the visual art media to create a visual message, or compose a musical
piece.
Geography
Examine a satellite mosaic of Earth from space (you can find
them on weather-related web sites, such as the Dallas Remote Imaging Group:
http://www.drig.com/). If you were from another planet, and you were
designing your first mission to Earth, where would you choose to land?
(Give latitude and longitude.) Why there? What scientific objectives
would your mission have? What image source did you use?
Journal writings and/or illustrations about your findings on
the websites listed under Action Plan.
Science
Write a letter to one of the scientists interviewed on the tape,
asking for clarification of his/her statement or for additional information
about the statements made.
Implement lessons from the Teacher's Guide for Live From
Mars. This Guide may be obtained by contacting:
Passport to Knowledge - Live From Mars
phone: 1-800-626-LIVE
http://quest.arc.nasa.gov/mars
Atmospheric Comparisons: Earth and Mars
1. The data table below shows the variation in pressure and
density with changing elevation for Earth and for Mars. Plot two graphs,
one to show pressure changes and the other to show density changes. On
each graph, plot elevation on the Y-axis. You may choose to use two
different scales on the X-axis, one for Earth data and one for Mars data.
Use one symbol for the Mars points and a different symbol for the Earth points.
Connect the points for Earth values with a smooth line; connect the Mars
points with a separate smooth line so that you can compare the atmospheric data.
2. What can you infer from these data?
3. If you plotted your graphs using different scales for the
X-axis, what would the graphs look like if you had used the same X-axis scale
for Earth and Mars data?
Or, if you plotted your graphs using the same scales for the
X-axis, what would the graphs look like if you had used different X-axis scales
for Earth and Mars data?
Earth
| Elevation Above Sea Level (km) |
Pressure
(mb) |
Density
(kg/m3) |
| 0 |
1013.25 |
1.225 |
| 2 |
794.95 |
1.007 |
| 4 |
616.40 |
0.819 |
| 6 |
471.81 |
0.660 |
| 8 |
355.99 |
0.525 |
| 10 |
264.36 |
0.413 |
| 20 |
54.75 |
0.088 |
| 30 |
11.72 |
0.018 |
| 40 |
2.78 |
0.004 |
| 50 |
0.76 |
0.001 |
Mars
| Elevation above datum (km) |
Pressure *
(mb) |
Density *
(kg/m3) |
| 0 |
6.1 |
0.20 |
| 2 |
|
0.12 |
| 4 |
|
|
| 6 |
2.0 |
0.05 |
| 8 |
|
|
| 10 |
1.2 |
0.009 |
| 20 |
0.8 |
0.002 |
| 30 |
0.4 |
0.0008 |
| 40 |
0.1 |
0.0003 |
| 50 |
0.08 |
0.00009 |
* values are highly approximate
Science from Sojourner
FOCUS FOR VIEWING
Segment A
What is Matt Golombek's choice for MVP? Why?
What is Donna Shirley's choice for MVP? Why?
Segment B
The segment on "Marvelous Mars" tells about some
Earth-Mars comparisons and contrasts.
Watch for statements about:
volcanoes -
weather -
land area -
biggest difference -
Segment C
Scientists are human too, and they respond to questions
differently. What do the scientists say in response to these questions:
1. Ares Vallis was the chosen landing site in hopes of
finding clear evidence of liquid water. Did it succeed?
Matt Golombek -
Ron Greeley -
2. Did they find a collection of rocks swept together by
ancient floods?
Matt Golombek -
3. What interesting things were learned from the robot
explorer?
Matt Golombek -
Ron Greeley -
Joy Crisp -
Which scientist do you think is most clear and easy to
understand? Why?
Rephrase, or translate into your own words, the responses of
the scientists. What did you NOT understand? What else would you
like to know from these scientists?
Segment D
According to Golombek, what 4 things have we learned from
Pathfinder?
1.
2.
3.
4.
Segment E
View the next segment without taking notes. Matt
Golombek speculates on what is would be like if we could stand on Mars.
Then view Segment E again. This time, write down adjectives and images
used in Matt's description of how he imagines the Mars surface environment.
What other descriptive phrases can you add to Matt's list?
What questions do you have about what it would be like to be on Mars?
Science from Sojourner
FOCUS FOR VIEWING
TEACHER'S VERSION
Segment A
What is Matt Golombek's choice for MVP? Why?
Rover going down ramp to surface of Mars, because it
shows that the rover works
What is Donna Shirley's choice for MVP? Why?
Sojourner measuring chemistry of Barnacle Bill with
APXS
Segment B
The segment on "Marvelous Mars" tells about some
Earth-Mars comparisons and contrasts.
Watch for statements about:
volcanoes - both have volcanoes; Olympus Mons is
largest in solar system
weather - both have winds and clouds
land area - about the same for Earth and Mars if you
look at just land area (exclude ocean area on Earth)
biggest difference - life on Earth vs. lifeless Mars
(in modern times, and as far as we know)
Segment C
Scientists are human too, and they respond to questions
differently. What do the scientists say in response to these questions:
1. Ares Vallis was the chosen landing site in hopes of
finding clear evidence of liquid water. Did it succeed?
Matt Golombek - mouth of outflow channel;
depositional plain of sediment like Washington's Channeled scablands
Ron Greeley - documented existence of liquid water
in the past on Mars; therefore the climate must have changed
2. Did they find a collection of rocks swept together by
ancient floods?
Matt Golombek - a variety of soils were found;
variety among rocks is yet to be determined
3. What interesting things were learned from the robot
explorer?
Matt Golombek - rover mobility is fundamental to
sampling
Ron Greeley - composition of Barnacle Bill has high
silicate content, indicating that the magma and crustal materials have been
processed. (This means that the planet did not form in just one geologic
episode -- there is a long geologic history still to be worked out.)
Joy Crisp - not all rocks are basaltic (again
implying a geologic history with many events)
Which scientist do you think is most clear and easy to
understand? Why?
Rephrase, or translate into your own words, the
responses of the scientists. What did you NOT understand? What else
would you like to know from these scientists?
Segment D
According to Golombek, what 4 things have we learned from
Pathfinder?
1. Mars is a differentiated planet with a core,
mantle, and crust.
2. Water-worn conglomerates require liquid water to be
stable with the atmosphere; therefore Mars was once warmer and wetter than it is
today.
3. Sand-sized grains exist on Mars, therefore
weathering and erosion processes that generate sand must exist or existed in the
past.
4. Temperature is falling; autumn is approaching.
Segment E
View the next segment without taking notes. Matt
Golombek speculates on what is would be like if we could stand on Mars.
View Segment E again. This time, write down adjectives
and images used in Matt's description of how he imagines the Mars surface
environment.
salmon-colored sky, early morning clouds, sunrise,
rock-strewn field, footprints, change in temperature of about 20° from feet to
head, 10° to 20° temperature swings, light breezes
What other descriptive phrases can you add to Matt's list?
What questions do you have about what it would be like to be on Mars?
Updated: April 01, 2008
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