Global menu

Your Birthday on Another Planet

  • Planétarium
When would your next birthday be if you lived on another planet?
Photo: NASA

Tabs group


Description of the activity

When would your next birthday be if you lived on another planet? Students may believe that the planets all revolve around the Sun at the same speed or take the same amount of time to complete one orbit  around the Sun. Some students might not know that all the planets revolve around the Sun in the same direction.


By assembling and using the solar system flip book, students realize that the four planets closest to the Sun (Mercury, Venus, Earth and Mars) revolve around the Sun in the same direction, albeit at different speeds. Students use this visual information, along with a table showing the orbital period of the planets in the solar system, to deduce that the length of a “year” isn’t the same from one planet to the next. They conclude that their birthdays wouldn’t be celebrated at the same frequency on these planets as on Earth.

Equipment needed by the student

For each student (or each team):

  • Thick paper (index cards or file folders)
  • Photocopies of planetary orbit sheets numbered 1 to 24 (Appendix 1)
  • Glue, scissors
  • Coloured pencils
  • Stapler or large clips for holding together a stack of 24 sheets of thick paper
  • Photocopies of the table of the planets’ revolution periods (Appendix 2)
  • Photocopies of the student handout Your Birthday on Another Planet


Gather the supplies needed and copy out the quiz questions on the board. Identify a source of information on planets that students can consult, whether it be the table in Appendix 2 or an astronomy book from your school’s library (preferably a recent publication).


  1. In front of the class, explain the steps for assembling the solar system flip book. (Refer to the handout.)
  2. Explain to students that once they’ve finished, they can observe the orbital movement of the planets by holding the flip book in one hand and quickly flipping through the pages with the other. Their flip book will work all the better if they’ve assembled it carefully. The planets should revolve around the Sun counterclockwise. To produce this effect, flip the pages from top to bottom.
  3. Make sure that students each assemble their flip book and flip through its pages several times till they’ve properly observed planetary movement.
  4. Once they’ve mastered the previous step, pass around the student quiz Your Birthday on Another Planet.


Adapted from Your Birthday on Another Planet by Ed Ruszczyk and Gary Sampson, Copyright © 1994 by the President and Fellows of Harvard College

Category of activity

  • Enrichment activity

Sub-category of activity

  • Class activity

Grade level

  • Elementary cycle two

Number of students per group

Individual activity or groups of four


Two 60-minute periods

Activity Sheets

Your Birthday on Another Planet[PDF - 163.83 KB - 12 pages]

Schedules for teachers

Add this