Learning Exercise

• Science and Technology  / Astronomy

• High School
• College General Ed
• College Lower Division

JavaScript is required for the interactive controls and graphs. Instructions, worked examples and data tables remain readable without JavaScript. Internet access is needed to open the website and download resources; downloaded worksheets and data can be used offline.

Chart descriptions and supporting data tables provide text alternatives to the visual plots. The printable PDF includes tagged headings, reading order, table headers and chart descriptions. For adjustable text and a reflowing layout, use the webpage; the PDF retains a fixed print layout.

Optional spreadsheet work uses CSV files. The optional verification script requires Python 3.9 or later, uses only the standard library and runs offline. It checks the supplied data and reference calculations; it does not fit a transit or independently confirm a planet.

Learners should be able to read a basic graph and perform subtraction, division, percentages and square roots. No prior astronomy, programming or telescope experience is required.

The online activity requires a modern web browser with JavaScript enabled and an internet connection. A calculator with a square-root function is recommended. Downloaded worksheets and data can be used offline; the printable packet requires a PDF reader.

Spreadsheet software supporting CSV files or Python 3.9 or later is needed only for the optional extensions. The Python script uses only the standard library. No account or paid software is required.

Exoplanets; transit photometry; Kepler mission; light curves; orbital period; phase folding; transit depth; planet-to-star radius ratio; scientific evidence and uncertainty.

• Group
• Student-centered
• Unsupervised
• Individual
• Core Activity
• Supervised

By the end of this exercise, learners will be able to:

1. Estimate an orbital period from recurring brightness dips by dividing elapsed time by the correct number of intervals.

2. Explain how phase folding rearranges existing observations without changing measured brightness or adding new data.

3. Calculate a fractional light deficit and estimate a planet-to-star radius ratio using the square-root relationship, while identifying its simplifying assumptions.

4. Construct a scientific explanation supported by two numerical observations, a limitation, an alternative explanation and a useful follow-up observation.

5. Distinguish transit-like dimming from the additional evidence needed to confirm a planet, recognizing that this activity reexamines an already established system.

Assess the completed worksheet or equivalent written response using this suggested 10-point rubric:

1. Period calculation and interval counting — 2 points.
   Correctly calculates an orbital period and explains why 14 consecutive dips span 13 intervals.

2. Phase-folding explanation — 2 points.
   Explains that folding rearranges the same observations without changing measured brightness, adding data or independently confirming a planet.

3. Light deficit and radius ratio — 2 points.
   Correctly calculates the fractional light deficit and approximate radius ratio, distinguishing fractions from percentages and identifying a simplifying assumption.

4. Evidence-based claim — 2 points.
   Presents a defensible claim supported by two relevant numerical observations.

5. Limitations and further investigation — 2 points.
   Identifies a relevant limitation, an alternative explanation and a useful follow-up observation.

Award partial credit within each category for sound reasoning despite minor arithmetic or wording errors. Accept sensible rounding; displayed decimal places do not indicate physical precision. Reward explanations supported by evidence.

Educator notes and worked answers are included in the downloadable teaching packet. Optional spreadsheet or Python extensions may be assessed separately.