Finding Solar Noon

Source: Pixhere

Type: Investigation

Theme: Modeling

Grades: 6, 7, 8, 9, 10, 11, 12

Learning Target: Students will use precision and accuracy while creatively developing a method to determine the exact time of solar noon at school on a particular day.


sundialThis project is for groups of two or three.

  1. Design a simple sundial that displays the shadow of a nail on grid paper (nail should be perfectly vertical).
  2. Determine the magnetic declination for your location, so you can align your sundial to true north.
  3. Place your sundial in the sun with grid paper aligning to true north.
  4. Throughout the day, add points with times on the grid paper to capture the 'curve' of the shadow as the sun moves across the sky (collect data as early and late in the day as possible in military time).
  5. Convert all times to decimal.
  6. Graph 'curve' using Desmos based on points from graph paper. The x-axis values should be the decimal-based time values, not the horizontal grid marks. As the shadlow of the tip of the sundial point falls onto a flat surface, it will trace out a conic section, such as a hyperbola, ellipse or (at the North or South Poles) a circle.
    1. High school students will regress their data to determine solar noon using a hyperbolic equation.
    2. Middle school students will estimate solar noon from values on the graph.
  7. Two paragraphs discussing your error:
    1. How was precision involved?
    2. Did low accuracy cause part of your error?
    3. What changes would have lessened your error?
  8. Respond to this question*: Why are clocks oriented so that the hands rotate clockwise while many other things in nature spin counterclockwise (Earth, hurricanes, most planets, etc.)?
  9. Obtain Peer Review. Revise.


  1. Compass
  2. Nail
  3. Graph paper
  4. Cardboard
  5. Tape (clear and duct or masking)
  6. Clock


  1. PowerPoint containing the following.
    1. Photograph of sundial.
    2. Artifacts describing process (photos, videos, etc.)
    3. Graph of 'curve' using Desmos.
    4. Measured Solar Noon time. 
    5. Actual Solar Noon time.
    6. Error in minutes:seconds (mm:ss).
    7. Two paragraph discussion.
    8. Response to question (#8) above.
  2. Peer Review.


*Hint: The answer is nested in the shadow of your sundial.

Exit Ticket
CCSS Math Practice
  • I can model with mathematics.
  • I can attend to precision.
NGSS Crosscutting Concepts
  • Systems and System Models


Example from Rayna and Chloe