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Investigating Planetary LifeInvestigating-Planetary-Life

  • Subject: Space Science
  • |
  • Grade(s): 9-12
  • |
  • Duration: Two class periods

Lesson Plan Sections

Objectives


Students will
  • Identify the variables that must be in place for life to develop.
  • Explain why scientists are investigating life on Mars
  • Describe the tools scientists are using in their search for life on Mars.
  • Discuss the most recent scientific findings about whether life has ever existed on Mars.

Materials


Procedures


  1. Begin the lesson by asking students to write on a piece of scrap paper their opinion about whether they think life exists elsewhere in the universe. Tell them not to show the paper to anyone and to put it away until the end of the lesson.


  2. Have students watch the programInvestigating Planetary Life . Then briefly discuss it with the class. Make sure students understand that this is a fictional account of where life might be in the universe and what it might look like. Explain that they will be learning about how scientists are searching for life elsewhere in the universe, and in particular, on Mars.
  3. Divide the class into groups of four. Tell each group that their task is to research the scientific search for life on Mars and to develop a visual display describing this process. Each display should include the following items.
    • A description of Mars
    • Early scientific efforts to look for life on Mars
    • Recent efforts to look for life on Mars, with an emphasis on scientific tools
    • A discussion of the most recent findings
  4. Give students time in class to work on their projects. The following Web sites have information on this topic.

    Mars
    Images For Spirit and Opportunity
    Just Keeps Going and Going...
    Life on Mars
    Life on Mars?
    I Found Life on Mars in 1976, Scientist Says
    Rover Data Makes Return a Must


    Basic Information
    Possible Sites for the Origin of Life

     
  5. For your information, below is some background material on this topic.
    • To date, Mars is the only planet that has shown evidence that water may have existed on it at one time.
    • In 1976 the Viking I and II probes landed on Mars. At the time, they were the most sophisticated probes ever to land on a celestial object. The probes gathered soil samples and performed many experiments in search of signs of life; most scientists agreed that life on Mars did not exist. One scientist, Gilbert Levin, claimed that his experiments showed that some form of life was present in the soil.
    • Recent efforts to look for life on Mars, with an emphasis on scientific tools
    • In 2004 NASA (National Aeronautic Space Agency) sent two state-of-the-art robots, Spirit and Opportunity, to explore Mars. The images they sent to Earth confirmed the suspicion that water in some form did exist on Mars at one time. Water is essential for life.
    • Spirit has stopped sending data to Earth, but Opportunity is still functioning. Based on recent data, scientists have concluded that while water was present on Mars, other conditions may have made the development of life difficult. At this point, scientists question whether the conditions needed for a key set of chemical reactions to take place were ever present there. If these chemical reactions could not take place, the probability of life developing would be lower.
    • The search for life on Mars is ongoing. Scientists will continue to analyze new data and develop theories as information becomes available.
  6. During the next class period, give students time to finish their displays. Then have each group present its findings. Discuss any themes that are evident in all the displays. Based on the data available, do students think that life has existed on Mars?
  7. Conclude by asking students to look at their answer to the question about whether life exists elsewhere in the universe that they recorded at the beginning of the lesson. Have students' ideas about this topic changed? Do they think that scientists may answer this question during their lifetimes?

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Evaluation


Use the following three-point rubric to evaluate students' work during this lesson.
  • Three points:  Students thoroughly explained the variables that need to be in place in order for life to form; demonstrated a clear understanding of why scientists are looking for life on Mars; demonstrated a clear understanding of the way research has progressed in this area.
  • Two points:  Students satisfactorily explained the variables that need to be in place in order for life to form; demonstrated an adequate understanding of why scientists are looking for life on Mars; demonstrated a satisfactory understanding of the way research has progressed in this area.
  • One point:  Students had difficulty explaining the variables that need to be in place in order for life to form; demonstrated a weak understanding of why scientists are looking for life on Mars; demonstrated a weak understanding of the way research has progressed in this area.

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Vocabulary


exobiology
Definition: The branch of science that focuses on the search for life outside Earth elsewhere in the universe.
Context: Many people believe that life must exist elsewhere in the universe, and a field of science called exobiology is dedicated to finding out if it does.

Mars
Definition: The fourth-closest planet to the sun, Mars has a reddish surface that can be seen from Earth.
Context: In addition to signs that water may once have been present on Mars, scientists also have found that the surface conditions on Mars are closer to those on Earth than are those of any other planet, adding further support to the idea that life may exist there.

Spirit and Opportunity
Definition: Two robots sent to Mars that have successfully sent data to Earth.
Context: Spirit has stopped operating, but Opportunity continues to send important information about Mars to Earth.

Viking probes
Definition: Two spacecraft sent to study Mars in 1976; at the time, they were highly sophisticated research tools.
Context: Based on an analysis of soil samples picked up by the Viking probes, most scientists concluded that it would have been impossible for life to have existed on Mars.

water
Definition: A compound of hydrogen and oxygen; thought to be a required variable for the formation of life.
Context: Although there is evidence that water existed on Mars, scientists stress that this doesn't mean that the planet can support life.

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Academic Standards


Mid-continent Research for Education and Learning (McREL)
McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education addresses 14 content areas. To view the standards and benchmarks, visithttp://www.mcrel.org/.

This lesson plan addresses the following national standards:
  • Space Science: Understands the composition and structure of the universe and the Earth's place in it
  • Language Arts-Viewing: Uses viewing skills and strategies to understand and interpret visual media
National Academy of Sciences
The National Academy of Sciences provides guidelines for teaching science in grades K-12 to promote scientific literacy. To view the standards,click hereto visit this Web site.

This lesson plan addresses the following national standards:
  • Earth and Space Science: Earth in the solar system

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