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  • Tips & Modifications

    Tip Teacher Tip

    To save your students' data for grading online, register your class for free at the High-Adventure Science portal page.

    Tip

    The activity is part of a sequence of activities in the Is There Life In Space? lesson. The activities work best if used in sequence.

    Modification

    This activity may be used individually or in groups of two or three students. It may also be modified for a whole-class format. If using as a whole-class activity, use an LCD projector or interactive whiteboard to project the activity. Turn embedded questions into class discussions. Uncertainty items allow for classroom debates over the evidence.

    1. Engage students in a discussion about eclipses.

    Explain to students that in a solar eclipse, the Moon moves directly between the Earth and Sun. Tell them that an eclipse may be total, in which the Moon appears to block the entirety of the Sun, or partial, in which the Moon blocks only a part of the Sun. Ask:

    • What happens to the Sun's brightness, as seen from Earth, during a solar eclipse? (When the Moon moves between the Sun and Earth, the Sun appears to dim.) 
    • Which type of eclipse causes more dimming effect, as seen from Earth: a partial eclipse or a total eclipse? (A total eclipse will cause more dimming because the entire face of the star is blocked. During a partial eclipse, there is less dimming because the Moon does not completely obscure the Sun.)

    Tell students that scientists use planetary eclipses to find planets around stars. As the planets move around their stars, they can block some of the light from that star, just as our Moon can block light coming from our Sun during a solar eclipse.

     

    2. Discuss the role of uncertainty in the scientific process.

    Introduce students to the concept of uncertainty in the scientific process. Explain that science is a process of learning how the world works and that scientists do not know the “right” answers when they start to investigate a question. Tell students that they can see examples of scientists' uncertainty in determining whether or not the data collected from telescopes show the presence of planets.

     

    Show the Kepler Planet Candidates graph from the NASA Exoplanet Archive. Tell students that the red dots indicate potential planets the Kepler telescope has detected and the blue dots indicate the planets the Kepler telescope detected and have been confirmed by other means. Ask:

    • Why do you think there are more red dots than blue dots (more potential planets than confirmed planets)? (The telescope may detect planets that are not there. The technology may not be good enough to tell the difference between a planet and some other phenomenon.)
    • Why do scientists need to independently confirm the presence of planets? (Scientists need to check the accuracy of the telescope's predictions of a planet. If the telescope shows a planet and the scientists confirm that it is a planet, then the scientists can spend more time trying to learn about the planet.)

    Let students know that they will be asked questions about the certainty of their predictions and that they should think about what scientific and model-based data are available as they assess their certainty with their answers. Encourage students to discuss the scientific evidence with each other to better assess their level of certainty with their predictions.

     

    3. Introduce and discuss the use of computational models. 

    Explain the concept of computational models, and give students an example of a computational model that they may have seen, such as forecasting the weather. Project the NOAA Weather Forecast Model, which provides a good example of a computational model. Tell students that scientists use planetary models to predict the motion and apparent brightness of stars if planets are present and to predict the habitability of planets. Explain that there are many different types of models and that they will be using simple models of planetary motion in this activity.

     

    4. Have students launch the Hunting for Planets interactive.

    Provide students with the link to the Hunting for Planets interactive. Divide students into groups of two or three, with two being the ideal grouping to allow students to share computer work stations. Tell students they will be working through a series of pages of data with questions related to the data. Ask students to work through the activity in their groups, discussing and responding to questions as they go.


    NOTE: You can access the Answer Key for students' questions—and save students' data for online grading—through a free registration on the High-Adventure Science portal page.

     

    Tell students this is Activity 3 in the Is There Life in Space? lesson.

     

    5. Discuss the issues.

    After students have completed the activity,  bring the groups back together and lead a discussion focusing on these questions:

    • How does a planet's size affect its ability to be discovered via the transit method? (The transit method relies on detecting dimming of a star as planets orbit. If the planet is very large, it can block more of the light coming from the star. A high level of dimming is easier to detect than a smaller level of dimming. Therefore, larger planets are more likely to be detected than smaller planets.)
    • How does the angle of orbit affect a planet's ability to be detected? (A planet needs to orbit in the same plane as the scientists' telescopes to be able to be detected reliably. This is particularly important when using the transit method. If the telescope is even slightly out of the orbital plane, the dimming will not be detected. The wobble (radial velocity) method is more robust, since that depends on detecting motion (wavelength shift) of the star, not the brightness of the star.)
    • How does telescope “noise” affect planet hunting? (Scientists are more likely to discover larger, heavier planets than smaller, lighter ones because of the effect of telescope noise. The signals from smaller, less massive planets are smaller than the signals from larger, more massive planets. The smaller signals can get lost in the data “noise,” making it difficult to determine whether a planet is present.)

    Informal Assessment

    1. Check students' comprehension by asking students the following questions:

    • How are planets found via the transit method?
    • Why can't scientists use the transit method to find planets orbiting at a 45-degree angle?
    • If there is no dip in a star's light intensity, does that mean that there is not a planet orbiting that star?
    • How does a planet's diameter affect scientists' ability to detect it via the transit method?
    • How does a planet's size affect whether it can be discovered via the transit method?
    • How does the angle of orbit affect whether a planet will be detected via the transit method?

    2. Use the answer key to check students' answers on embedded assessments.

  • Subjects & Disciplines

    • Space sciences
  • Science
    • Earth science