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 Voyage to the Mystery Moon Viewing Ideas

Before Watching

1. The evening before showing the program, have students observe the night sky. Ask them to share their observations the following day in class. Did they see any stars? Planets? Moons? Tell students that there are at least 156 moons in our solar system. Jupiter's moon Ganymede is the largest, and Saturn's moon Titan is the second largest. (Scientists have currently identified 47 moons orbiting Saturn.) Both moons are larger than the planets Mercury and Pluto. Ask student pairs to write a definition for the term moon. Have pairs share their definitions, then use definition parts that are accurate to write a clear definition. (A moon is a natural satellite rotating around a planet. Moons are smaller than the planets they orbit. Some moons might be asteroids captured by planets.)

2. Saturn is about 1.3 billion kilometers from Earth (distance when Saturn and the sun are at opposite sides of the Earth) and has an equatorial radius about 9.5 times greater than Earth. To help students better understand the relative distances between, and the relative sizes of, Earth and Saturn, Earth and its moon, and Saturn and Titan, use a set of balls and string to represent the distances and sizes. Provide teams with the following materials: string, scissors, metric ruler, and four different-sized balls to represent the celestial bodies (small marble, large marble, ping pong ball, basketball). Before beginning, have students predict the distances between Earth and Saturn, Earth and its moon, and Saturn and Titan. Then write on the board the information in the first two columns of the "Planet and Moon Chart" and the "Distances Chart." Also write the string length for the distance from Earth to Saturn (10 meters).

Tell students that the models they will be making represent relative, not actual, size differences based on the equatorial radius of each celestial body. After providing students with the formula for calculating, have them calculate the ratios as compared to Earth (Earth = 1), determine which ball to use to represent each celestial body, and calculate the string lengths representing the distances between Saturn and Titan, and Earth and its moon, using the formula provided. Have teams display the celestial bodies and their relative distances from each other on the floor in the classroom.

Planet and Moon Chart

 Equatorial Radius (km) Ratio (Relative to Earth) Ball to Represent Celestial Body Earth 6,378 1 ping pong ball Earth's moon 1,737 0.27 small marble Saturn 60,268 9.5 basketball Titan 2,575 0.40 large marble Formula for calculating ratio relative to Earth: celestial body's equatorial radius/Earth's equatorial radius = size relative to Earth

Distances Chart

 Distance (km) String length (meters) Earth to Earth's moon 384,400 0.003 m (3 mm) Saturn to Titan 1,221,850 0.01 m (1 cm) Earth to Saturn 1,277,420,000 10 m Formula for calculating string length: * 10 m/Earth to Saturn distance = X/Saturn to Titan distance (Cross-multiply and solve for X or string length for Saturn to Titan distance) * 10 m/Earth to Saturn distance = X/Earth to Earth's moon distance (Cross-multiply and solve for X or string length for Earth to Earth's moon distance.)

3. Ask pairs of students to calculate how long it would take a spacecraft traveling in a straight line at 60,000 kilometers per hour to reach Earth's moon from Earth, Saturn from Earth, and Titan from Saturn. Tell students that although these numbers aid in understanding the vast distances between the bodies, they are not accurate, because spacecraft are sometimes plotted on more roundabout routes where they can gain an extra boost from gravitational encounters with planets.

Space Travel at 60,000 km/hr

 Destination Distance (km) Time Earth to moon 384,400 6 hours 24 minutes Earth to Saturn 1,277,420,000 2 years 5 months Saturn to Titan 1,221,850 20 hours 22 minutes

4. Organize the class into three groups and as students watch the program, have each group take notes on one of the following topics: how the Cassini spacecraft traveled to Saturn, what Cassini learned about Saturn's rings, and what Cassini and the Huygens probe revealed about Saturn's moon, Titan.

After Watching

1. Have students who took notes on the same topic meet, compare their notes, and then share what they learned with the class. What planets gave Cassini an extra boost on its journey to Saturn? What did scientists learn about the formation of Saturn's rings? What characteristics about Titan's atmosphere make it potentially suitable for life?

2. The Cassini spacecraft and the Huygens probe are types of robots. Have students share what they know about robots. Define the term robot for students. (A robot is an electronically controlled device that is capable of performing human tasks, often in harsh or hazardous environments or in situations in which constant repetitions are required.) Ask students if they have or know of any robots that fit this definition. (Some examples include self-contained pool vacuum cleaners and the Mars Pathfinder.) Ask how the Cassini spacecraft and Huygens probe fit the definition for a robot. (They were outfitted with instruments and sent to Saturn to study the planet, its rings, and its moons. They were controlled by computers.) Show students a picture or diagram of the spacecraft. (See Links & Books for Web sites that include photos and artwork of Cassini.)

The functions of many spacecraft parts can be compared to humans or human activities. As a class, discuss the function of some of the Cassini spacecraft parts, and have students brainstorm a human parallel or activity related to the function.

 Cassini spacecraft part Function Human parallel or activity Huygens Probe separates from Cassini and analyzes Titan's atmosphere and surface parachute jumper Spacebus provides framework for all components body's frame Engines provide thrust for movement metabolism, mitochondria in cells Computers stores and send information brain, mind, nervous system Antennas allow communication between Cassini-Huygens and scientists on Earth hearing and speaking Cameras take pictures sight

To help students begin to develop a sense of the details involved in accurately programming spacecraft computers to fly specific flight paths and perform specific functions (the Cassini spacecraft has more than 40 computers), pair students and ask each partner to write directions for a simple task on an index card. (Tasks might include putting a barrette in hair, combing hair, putting on a sweater, tying shoes, watering a plant, or packing a bookbag.) Have each student take turns reading the steps (without identifying the task) while the other student (the robot) performs them exactly as they are read. Have students revise their directions based on how their robot team member performed the task. When students have finalized their directions, have each team trade task cards with the nearest team so that they can test each other's final directions. If needed, have the teams that now have new sets of directions work to further refine the directions using the process above before passing a final set of directions back to the original team for final testing.

Web Sites

Cassini-Huygens: Mission to Saturn and Titan
saturn.jpl.nasa.gov/multimedia/images/
Includes images and artwork of the Cassini spacecraft, Saturn, Saturn's rings, Saturn's moons, and more.

Saturn Controls a Giant Planetary System
www.spacetoday.org/SolSys/Saturn/SaturnMoonsRings.html
Features the latest Cassini news from Saturn and information about the mission, Saturn's moon, its rings, and other moons of the solar system.

Saturn's Moons
solarsystem.nasa.gov/planets/profile.cfm?Object=Saturn&Display=Moons
Provides a brief description of some of Saturn's moons.

Saturn's Moons and Rings