Looking for Young Features on Europa
an image analysis simulation
Teachers, your students can study the most recent pictures of Europa taken
by the Galileo spacecraft. Using a Color Macintosh or Mac clone, free software,
lesson, and images, your students will simulate the scientific adventure
of peering at new worlds. Learners will simulate the work of project scientists,
investigating geological features of the Jovian moon Europa. Science students
will evaluate one image to determine the relative geological age of discreet
features in one region of Europa. This qualitative analysis will lead student
investigators to experience science using scientific tools.
Note for Windows 3.1 and Windows 95 users- Scion Corporation is making
NIH Image work on Wintel Computers. The program is called Image PC. Recently
out of alpha and into beta version 1 testing, it is available at http://www.scioncorp.com.
PC users be aware of the following 3 facts:
- This lesson was created and tested on Macs.
- All beta software is buggy and may cause your machine to crash. Tracking
and reporting your crashes to Scion will improve the product.
- Let me know if you successfully used this lesson on a Wintel computer.
Scott Coletti (scolett@quest.arc.nasa.gov)
Creator of this activity
Table of Contents
How to Download the Lesson Package
Setting up the Mac Desktop for a Quick Start
Why Image Analysis in Education
Summary of Digital Imaging
Lesson Brief
Lesson Plan
Learner Handout (4 pages)
Resources
HOW TO DOWNLOAD THE LESSON PACKAGE
Before downloading this TIFF lesson image make sure to download the
application (NIH Image). Once you have installed NIH Image in your computer,
set Netscape to use NIH image to view TIFF files. You set Netscape to
use NIH Image by doing the following:
- Go to Options in the command line.
- Select the menu item General Preferences in Options Menu.
- Select Helper card and scroll down until you can select the extension
"TIFF".
- Click the browse button until you find the application NIH Image in
your computer. Select NIH Image in the dialog box, set the file type
to "TIFF" and click apply.
- Make sure to select Launch application or save file from the action
options in the Netscape dialog box, depending on how much memory you
have.
The Lesson Image-Image Title: Prominent Doublet Ridges on Europa
http://quest.arc.nasa.gov/galileo/features/li.tiff
The Anticipatory Set Image-Planetary image of Europa in natural and
false color
http://quest.arc.nasa.gov/galileo/features/ai.gif
SETTING UP THE MAC DESKTOP FOR A QUICK START
When I introduce a new lab to my students, I often use the Mac alias
capability for ease of use.
To create Aliases of any file take the following steps:
- Click one time on any file to select.
- Go to the word File in the Command line.
- Go to the menu Item in File called Make Alias. and let go)
In this lesson I created an alias of both the Full Europa/PICT and the
Doublet/TIFF/grid/amber/9.x images. I drag those 2 Aliases to the bottom
of the Desktop. I have kids double click on the Alias of the image for
the anticipatory set. The Mac automatically launches ClarisWorks and loads
the image to the screen. When done with the anticipatory set the kids
just quit ClarisWorks and double click the lesson image Alias to automatically
launch NIH Image.
WHY IMAGE ANALYSIS IN EDUCATION
Remember the old Chinese proverb...something about hearing and forgetting,
seeing and learning, doing and remembering? Well, Image Analysis in Education
covers two of the three...the two that count the most.
The comical retort "Do I need to draw you a picture?" is an appropriate
example of a natural tendency of our species to be primarily visual. We
start in kindergarten with the calendar: day, date, and pictures of brown
leaves decorating October. Hey, it works, so we do it.
Who of us involved in teaching has not struggled to make difficult concepts
simple and easy to understand. And who, involved in this struggle has
not turned time and again to visualizing information as an obvious solution:
a solution that offers a way to see the unseen. This seeing the unseen
is a fundamental tenet of Imaging in education.
The primary grades are full of visual information conveyances: big books,
flash cards, multiplication tables and this-is-the-way-to-throw-the-ball,
junior; in the middle school years: the skeleton in the lab closet, the
Mercator effect, atoms (when will it be gluons?), stars and planetary
mobiles, cell models, and catapult contests so students can see Newton's
law at work. It is no secret to great teaching that to see an object does
wonders for the transfer of ideas.
The concept of visualizing information is not new to teachers. This
is the point I want to hammer home: visualizing information is a normal
way for the species to go about the business of discovery.
Imaging in Education, the subject I am introducing, simply adds to the
teachers tool box the capabilities of the computer to manipulate images
in the service of understanding. This image manipulation makes invisible
information visible.
SUMMARY OF DIGITAL IMAGING
Computers can only see what they see as numbers and computer images
are no more than a string of numbers. Those numbers control what the computer
displays on a screen. The numerically-controlled computer shoots electrons
at the back of the screen where several colors of phosphor are painted.
The phosphor gets excited by the electrons and in the excitement becomes
luminous. If it is a red phosphor, it glows red; green glows green; and
blue, blue. Through various technologies, these three dots of color together
can be seen as any color of the rainbow. Each dot has a fancy computer
name. The dots are called Pixels. Pixel stands for Picture Element. Most
computers can send at least 256 colors to each dot (pixel) on the screen.
It is the manipulation of these dots that we call digital imaging. In
fact the free program used to analyze this lessons image acts on the pixels
on the computer screen.
Let me introduce you to this free software that works on the Apple Macintosh
computer,called NIH Image. It does one job brilliantly. Its mission in
life is to help humans analyze pixels, one at a time, a group of 9, or
an array of 300,000. It slices; it dices. It can graph, plot, measure,
and create data sets (which you can export to your favorite spreadsheet
for graphing, by the way). Among other functions, NIH Image can magnify
the image, edit, enhance, apply a new coat of colors and teach an old
dog new tricks.
LESSON BRIEF
THE TOOLS
In this lesson I will introduce you to 4 tools in the NIH Image programs
tool box. The tools are:
Grabber Hand
Magnifying Glass
Color Tables
Look Up Table Tool
THE IMAGE
The image used in this lesson is indeed beautiful. Much has been and
is being discovered by analyzing the original data of this image. The
copy we work with clearly shows various features and their local relationships.
Using image analysis allows students to make qualitative observations.
(for the technically minded this image is provided in a TIFF file format
after conversion from the JPEG file. The full digital images necessary
for scientific analysis will be released for analysis within one year
after receiving each orbits last data.
GALILEO: THE MISSION
Right now our species has a satellite named Galileo orbiting the Jovian
System 500 million miles away. It took almost seven years for Galileo
to travel from Earth to where it now circles the large gas giant. Galileo's
mission: to send back observations of the planet and its moons.
Galileo's Solid State Imaging camera can "see" wavelengths that run
from 416 to 989 microns (blue to near infrared).
Galileo sends back its precious information in a journey that, at the
speed of light, only takes about one class period to get from Jupiter
to Earth. Arriving home, the data are picked up by a global system of
antennas called the deep space network. The data stream is sent to NASA's
Jet Propulsion Laboratory (JPL) in Pasadena, California . Once at JPL
the information from the sapcecraft is validated and calibrated for distribution.
On Feb 20 Galileo flew by one of the most intriguing of Jupiter's 16
natural satellites, Europa. Pictures of this moon's surface taken from
only 370 miles away showed features ranging from as small as a van to
the size of a city building. These pictures will expand the coverage and
resolution from our past imaging attempts of Europa with Voyager I and
II.
EUROPA
When Galileo Galilei first turned a telescope to look at Jupiter, he
saw four "wandering stars" orbiting the planet. Of these four, Europa
is the second moon out from Jupiter. It measures about the same size as
our moon in diameter, yet it is the smallest of Jupiter's 4 main moons
(or what are now known as the Galilean satellites). By viewing Europa
with infrared sensors it is possible to detect water in the form of ice
on its surface.
The geology of this moon appears to be shaped, in part, from the movement
of material that has been forced up from below the surface. The surface
may be geologically young (perhaps only a few tens of millions of years
old) Indications that material has been upwellings from the interior is
helping scientists to figure out what lies under Europa's surface.
Europa is an icy, slushy moon, torn by global forces related to tidal
surges and swells in response to Jupiter's gravitational pull. The icy
moon is also ripped at by the supplemental tidal forces of the other Galilean
moons Ganymede (the third moon), Callisto (the fourth moon) and Io (the
first moon).
Planet-wide compressional and/or extensional movement is revealed in
surface features. Geological activity in the form of what scientists call
"ice volcanoes" appears to have sent material up through trenches,thousands
of miles long, which riddle this moon's surface with a seemingly chaotic
network of cracks. These ridges are the dominant feature, appearing as
light and dark bands traversing the face of this moon. All of Europa's
geological activity has created a relatively smooth surface where no elevation
extends higher than a couple thousand feet. An elevation that would only
warrant use of the term "hill" here on Earth (by comparison, the tallest
mountain on Earth, Mauna Kea, is over 33,476 feet in elevation from sea
floor to peak). This billiard ball-smooth moon is five times brighter
then our own lunar landscape.
While the dominant feature on Europa is light and dark banding, other
features have also been identified by planetary geologists. These features
include impact craters, domes, crisscrossing lines, mottled terrain, disrupted
terrain, gray bands, bright patches (high albedo areas), small knobs,
raised platforms and dark patches referred to as "freckles".
The Hubble Space Telescope has imaged a tenuous atmosphere on Europa.
Scientists theorize that all the forces acting on this moon are raising
gaseous water from its surface.
Europa Quick-Look Statistics
Discovery: Jan 7, 1610 by Galileo Galilei
Diameter (km): 3,138km
Mass (kg): 4.8e22 kg
Mass (Earth = 1) 0.0083021
Surface Gravity (Earth = 1): 0.135
Mean Distance from Jupiter (km): 670,900km
Mean Distance From Jupiter (Rj): 9.5 Rj
Mean Distance from Sun (AU): 5.203AU
Orbital period (days): 3.551181days
Rotational period (days): 3.551181days
Density (gm/cm^3) 3.01 gm/cm^3
Orbit Eccentricity: 0.009
Orbit Inclination (degrees): 0.470degrees
Orbit Speed (km/sec): 13.74km/sec
Escape velocity (km/sec): 2.02 km/sec
Visual Albedo: 0.64
Surface Composition: Water ice
PERFORMING TEACHER DEMONSTRATION
After reading through Europa Brief for Learners in the Learner Handout
my 8th. graders had a good understanding of what they were looking at;
half the 7th. graders however, did not. I used the following demonstration
to help the next class understand what they were looking at.
First I gathered up the following materials: an old newspaper, pieces
of Yarn of various thicknesses and colors, and some red and blue water
base poster paint. With the paper on the floor and a puddle of blue paint
here and there, I began throwing yarn on the news print explaining as
I went along how various geological features might be shaped. The blue
paint puddles represent material that has come from underneath the surface.
The red paint splattered last, onto the newspaper and yarn represents
material that has come back down to the surface after being lofted in
the air by some event.
LESSON PLAN
ACTIVITY DESCRIPTION
Students analyze an image of Europa classifying surface features by
relative age
SUBJECTS:
Planetary Geology and the Scientific Process
TARGET AUDIENCE:
Middle School
TEACHER SKILL SET REQUIRED:
Mac-proficient science teacher with some experience (or help) using
the World Wide Web.
PURPOSE OF THE LESSON:
Given the Image titled Prominent Doublet Ridges on Europa (Image catalog
#PIA00542), a Mac, the program NIH Image and the lesson package titled
Finding Young Features on Europa, the learner will analyze the image,
making qualitative statements of the relative geological features of one
discrete region of the Jovian satellite Europa.
MEASURABLE OBJECTIVE:
All students on task 95 percent of contact time.
Many verbalizations of excitement and interest
Learner-generated statement that ages geological features (from youngest
to oldest) demonstrating an understanding of possible planetary geological
forces at work.
Mastery of vocabulary by use of word bank demonstrated by naming features.
Observation of Image navigation and feature location using coordinate
system.
MATERIALS AND EQUIPMENT USED:
Color Mac running system 7.0.1 or newer, with a minimum of 3 Mb of available
RAM. Minimum 12 inch monitor with the ability to display 256 colors (8
bit).
Web access to pick up all materials.
Software (NIH Image 1.61)
Image Processing for Teachers download site-
http://ipt.lpl.arizona.edu/IPT/NIHImage/
or
National Institute of Health download site-
http://rsb.info.nih.gov/nih-image/download.html
The Lesson Image
-Image Title: Prominent Doublet Ridges on Europa
Before downloading this TIFF lesson image make sure to download the
application (NIH Image). Once you have installed NIH Image in your computer,
set Netscape to use NIH image to view TIFF files. You set Netscape to
use NIH Image by doing the following:
- Go to Options in the command line.
- Select the menu item General Preferences in Options Menu.
- Select Helper card and scroll down until you can select the extension
"TIFF".
- Click the browse button until you find the application NIH Image in
your computer. Select NIH Image in the dialog box, set the file type
to "TIFF" and click apply.
- Make sure to select Launch application or save file from the action
options in the Netscape dialog box, depending on how much memory you
have.
http://quest.arc.nasa.gov/galileo/features/li.tiff
The Anticipatory Set Image
-Planetary image of Europa in natural and false color
http://quest.arc.nasa.gov/galileo/features/ai.gif
PREPARATION TIME REQUIRED:
- 2.25 hours total prep for beginners
- 45 minutes to down load everything
- 15 minutes to install program
- 15 minutes to print
- 60 minutes of learning curve for beginners (Reading the material and
doing the lesson beforehand)
STUDENT CONTACT REQUIRED:
- 80 minutes total contact
- (about two periods for 8th graders on grade)
- (about three periods for 7th graders on grade, with spring like
weather, on Valentines day, just before ski week ;-)
- 05 minutes to open Anticipatory Set image, enjoy and close.
- 05 minutes Step 1-Open Lesson Image and pass out Learner Handout
- 10 minutes Step 2-Play with tools for lesson
- 10 minutes Step 3-Annotate Europa Brief for Learners
- 10 minutes Step 4-Teacher Demonstration
- 10 minutes Step 5-Discuss grid, Identify, draw and write up oldest
feature
1st Class contact over
- 20 minutes Step 6-Identify, draw and write up features
- 10 minutes Step 7-Class, group, individual discussion/writing of evidence
for various events
ANTICIPATORY SET:
Bring up the full planetary image of Europa in natural and false color
on the computer monitor (or print a few color copies). Read Lesson Brief-Europa
or improvise ;-)
TEACHING STRATEGIES:
The learning experience will be constructive and hands on. Cross ability
help among students is encouraged.
CLOSURE:
10 minutes Step 8-Discuss/write/share/debate closure question
EVALUATION OF STUDENT WORK:
Learner Handout, discussion and ability to state case for aging features.
LEARNER HANDOUT
Learner Handout
Page # of 2
Name____________________Date_________Grade__________Class__
The Youngest feature of Europa: an image analysis simulation
Galileo's closest encounter with the Jovian moon Europa will happen
on Feb 20th, 1997. Galileos on board camera will send back pictures from
only 370 miles above Europas surface. We need to look for features that
would suggest presence of a liquid water. A first step in your imaging
training might be to figure out the relative age of the features in this
current image that was taken on Dec. 19, 1996. How old are these features?
If they are only the oldest features, then that might mean that any subsurface
liquid might be long gone. If they are among the youngest features, that
might mean that there is still some subsurface liquid. So, let's find
out which features are the youngest. One interesting question can be asked
as you age these features: Will certain features be consistent with the
existence of subsurface liquid water where we can invest future scientific
resources for further investigation?
Step 1) Double click on the image icon called Doublet Ridges at the
bottom of the desktop.
(You are looking at a picture of the Jovian moon Europa)
Page 2 of 4
Step 2) Use the magnifying glass and the grabber hand to take a good
long look at the image-
- The magnifying glass will let you see close up (this is called Zoom
In) wherever you click on the image. To reset the magnification back
to normal, double click the magnifying tool. To zoom out one step at
a time hold the option key down as you click the tool (notice the plus
sign changes to a minus sign when you hold the option key down and click).
The grabber hand lets you move the image around.
Step 3) Read the following Europa Brief for Learnersabout the image.
As you read, take notes along the right margin of your handout.
Europa Brief for Learners
This image of Jupiter's satellite Europa was obtained from a range of
7364 miles (11,851 km) by the Galileo spacecraft during its fourth orbit
around Jupiter. This orbit was Galileos first close pass of Europa. The
image spans 30 miles by 57 miles (48 km x 91 km) and shows features as
small as 800 feet (240 meters) across (a little smaller than the size
of a football field). The sun illuminates the scene from the right. The
large circular feature in the upper left of the image could be the scar
of a large meteorite impact. Clusters of small craters seen in the right
of the image may mark sites where debris lofted (thrown up) from this
impact fell back to the surface. Prominent doublet ridges over a mile
(1.6 km) wide cross the plains in the right
Page 3 of 4
part of the image; younger ridges overlap older ones, allowing the sequence
of formation to be determined. Gaps in ridges are where new surface material
has obliterated older preexisting terrain.
When discussing the image with your fellow investigators it will help
if everyone knows that the origin (x=0, y=0) is in the lower left corner.
For convenience call the square at the corner of origin (1,1) and each
square up and over to the right in sequence. The thumbnail at the beginning
of the learner handout is set up already.
Step 4) OPTIONAL
Watch as your teacher demonstrates how events and geological features
may cover each other, creating, destroying, and altering the surface of
Europa.
Step 5) To start your search for the youngest feature in this image,
investigators need to know where in the image a feature or evidence of
an event can be found. The first step is to locate the feature on the
image. Label the grid below as the thumbnail image on page 1 is already
labeled.
Page 4 of 4
Step 6) Now that you have a way of locating features on the grid, you
can name the major features, identifying them in relationship to each
other, oldest to newest. Use the word bank below to describe what you
see on the entry line below. You need to also draw each feature on the
grid above
FEATURE BY NAME LOCATION= ROW ( ), COLUMN ( ) RELATIVE AGE
Planetary science word bank- Impact, Crater, Debris, Slush, Dome, Reflection
(Albedo), Radiate, Mottled, Terrain, Crisscross, Knobs, Platform, Freckled
(low albedo), Brightness, Erupting, Geysers, Freeze, Tectonic, Force,
Tidal, Fault, Parallel, Fracture, Event, Geology, Europa, Jupiter, Artifact,
Meteor.
Step 7) What evidence of major geological event/s stands out in this
image?
Step 8) How did you go about deciding the relative age of each feature?
RESOURCES
As fascinated as I am with how digital imaging tools work. And how they
can effectively accelerate and compress learning, I have been brief in
conveying what the teacher needed to know to use this lesson. If you are
inclined to this same fascination, check out the following resources:
Computer Graphics
Donald Hearn, M Pauline Baker
Copyright 1986
Prentice-Hall, Inc.
Envisioning Information
Edward R. Tuft
Copyright 1990
Published by Graphics Press
Scientific Visualization:
Advances and Challenges
Edited by L Rosenblum, R A Earnshaw, et al
Copyright 1994
Academic Press Inc.
The Image Processing Handbook 2nd. Ed.
Russ, C. John
Copyright 1995
Published by CRC Press Inc.
The Visual Display of Quantitative Information
Edward R. Tuft
Copyright 1983
Published by Graphics Press
Also you can visit the world leader in imaging in education. Go to the
Image Processing for Teachers Web site http://ipt.lpl.arizona.edu/
The men and women who invented and maintain NIH Image at the National
Institute of Health (NIH) take no less then 3 pages describing the
glorious capabilities of NIH Image. There is also links to other imaging
resources.
http://rsb.info.nih.gov/nih-image/
If you thirst for more understanding of the difference between beautiful
pictures (eg,GIF,JPEG) and images with scientific merit (eg, TIFF, PDS,
FITS, DEM) your journey can start by joining the folks at the Image
Processing for Teachers (IPT), or joining their email list
http://ipt.lpl.arizona.edu
Other Resources used to create this introductory image lesson
Jet Propulsion Labs (JPL)
http://www.jpl.nasa.gov/galileo/
Online From Jupiter 97
http://quest.arc.nasa.gov/galileo
Science 10-18-96
V274, pgs.309-464
http://www.sciencemag.org/science/content/vol274/issue5286/
Image Processing for Teachers
http://ipt.lpl.arizona.edu/IPT/
National Institute of Health: Home for NIH Image.
http://rsb.info.nih.gov/nih-image/
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